Improving the Quality and Consistency of Australian Cherries to Ensure Market Access

Improving the quality and consistency of Australian cherries to ensure market access

Dr John Golding Department of Primary Industries

Project Number: CY10012 CY10012

This report is published by Horticulture Australia Ltd to pass on information concerning horticultural research and development undertaken for the cherry industry.

The research contained in this report was funded by Horticulture Australia Ltd with the financial support of the cherry industry.

All expressions of opinion are not to be regarded as expressing the opinion of Horticulture Australia Ltd or any authority of the Australian Government.

The Company and the Australian Government accept no responsibility for any of the opinions or the accuracy of the information contained in this report and readers should rely upon their own enquiries in making decisions concerning their own interests.

ISBN 0 7341 2973 4

Published and distributed by: Horticulture Australia Ltd Level 7 179 Elizabeth Street Sydney NSW 2000 Telephone: (02) 8295 2300 Fax: (02) 8295 2399

Horticulture Australia Ltd. Project CY10012 (July 2012)

FINAL REPORT

Improving the quality and consistency of Australian cherries to ensure market access

John Golding Nancy Leo Michael Rettke NSW Department of South Australian Research Primary Industries and Development Institute

Project Number CY10012. Improving the quality and consistency of Australian cherries to ensure market access

Research Team: John Golding. New South Wales Department of Primary Industries (NSW DPI). Locked Bag 26. Gosford NSW 2250. T: 02 4348 1926. F: 02 4348 1910. E: [email protected] Nancy Leo and Michael Rettke. South Australian Research and Development Institute (SARDI). GPO Box 397. Adelaide SA 5001. T: 08 8393 9400. F: 08 8303 9424. E: [email protected]; [email protected]

Project team Shashi Satyan, Barbara Blades, Matt Pearce, Kylie Crampton and Mark Bullot (NSW DPI); Darren Graetz (SARDI) and Barry McGlasson (University of Western Sydney).

Purpose of Report This report describes the results of a survey of cherry fruit quality in retail stores in the 2010/11 and 2011/12 seasons. The results illustrate the seasonal nature of cherry fruit and the need to focus on improving fruit quality in the orchard, at the packinghouse and at the retail level. A range of technical and industry recommendations are made to assist industry address these issues.

This project was funded by the cherry levy facilitated by HAL in partnership with Cherry Growers of Australia Inc. The Australian Government provides matched funding for all HAL's research and development activities. NSW Department of Primary Industries and SARDI provided on-going support and significantly contributed to the outcomes of this project.

Disclaimer Any recommendations contained in this publication do not necessarily represent current Horticulture Australia policy. No person should act on the basis of the contents of this publication, whether as to matters of fact or opinion or other content, without first obtaining specific, independent professional advice in respect of the matters set out in this publication. Contents

Media summary...... 4 Technical summary ...... 5 1. Introduction ...... 7 2. Fruit Quality Survey...... 8 2.1 Retail Survey ...... 8 Materials and Methods...... 8 Survey timing and locations ...... 8 Fruit sampling...... 8 Fruit quality assessment ...... 9 Testing of shelf / consumer life...... 10 Data presentation and analysis...... 11 Results and Discussion...... 12 Visual appearance of fruit ...... 12 Acceptability of fruit (rots and defects only) ...... 12 Visual appearance of fruit ...... 12 Defects...... 15 Pitting...... 19 Bruising ...... 19 Rots...... 21 Fruit quality parameters ...... 22 Firmness ...... 22 Total Soluble Solids ...... 24 Titratable acidity...... 27 Flavour ...... 30 Size ...... 34 Colour ...... 36 Stem quality parameters...... 37 Stem colour...... 37 Stem loss and stem pull force ...... 40 2.2 Analysis of the surveyed fruit...... 44 2.3 Length of time in the supply chain ...... 49 2.4 Quality change in the retail environment...... 51 Results and general discussion...... 51 Stem colour...... 51

Fruit firmness ...... 55 Bruising ...... 57 Fruit colour ...... 59 Fruit size ...... 60 2.5 Changes in fruit quality stored after purchase...... 61 Overall fruit quality ...... 61 Fruit colour ...... 63 Fruit firmness ...... 64 Stem colour...... 65 Stem pull force ...... 66 Fruit total soluble solids...... 68 Fruit acidity...... 68 Subjective sensory quality assessment...... 70 3. Preliminary identification of the causes of cherry fruit quality defects...... 72 Background ...... 72 Methods...... 73 Results...... 75 Discussion ...... 97 4. Managing fruit and stem quality after the packinghouse ...... 99 4.1 Preliminary survey of cherry retail display conditions ...... 102 Background and Methods ...... 102 Results Supermarket...... 103 Results. Independent Fruit and Vegetable Store ...... 109 Discussion...... 116 4.2 Effect of storage conditions on cherry stem browning ...... 118 Methods ...... 118 Results ...... 122 General discussion...... 137 4.3 Preliminary evaluation of different cherry packaging types...... 140 Methods ...... 141 Results ...... 142 Discussion...... 144 4.4 Use of coatings to maintain cherry fruit and stem quality...... 145 Effects of coatings on cherry fruit quality...... 146 Evaluation of existing coatings / waxes...... 146 Development of new coatings to maintain cherry fruit and stem quality...... 154 5. Technology transfer...... 158

6. Recommendations ...... 161 6.1 Specific recommendations to address the fruit quality issues identified in the project...... 161 6.2 Recommended R&D activities to address the key findings of the project..... 165 Acknowledgements ...... 171 References and further reading...... 172

Media summary

Cherries are regarded as a treat by consumers – something special that can attract a premium price. The cherry industry recognises that consistently delivering fruit that meets consumers’ expectations is critical. Surveys of fruit quality were conducted during the 2010/11 and 2011/12 cherry seasons from November to February in retail stores in Sydney and Adelaide. Due to the poor growing seasons, an over-riding observation was the high level of unacceptable fruit on the market. The main reasons for the unacceptable fruit were pitting, bruising and rots. These three reasons accounted for over ⅔ of all the major defects observed across the two seasons. Similarly, pitting and bruising were also responsible for ⅔ of the level of minor defects. A preliminary packing line survey of seven different cherry packing lines in NSW and SA in the 2011/12 season showed there were key points in the packing line (such as the cluster cutter and the final sorting / packing line) which need improvement. The addition of a one week storage period of fruit in the 2010/11 season showed that the average level of unacceptable fruit increased three fold. The progression of storage rots was the main contributor to the increase in unacceptable fruit when fruit was stored after purchase from the retailer. The sugar levels in the sampled fruit were low across the 2010/11 season, but were generally higher in the 2011/12 season. However inconsistent eating experiences caused by low and inconsistent sugar levels in the fruit have significant impacts on consumer acceptability and therefore need to be improved. The level of browning of the stems increased during retail display. A series of storage experiments showed the retail storage environment had a strong effect on stem condition and quality. Different packaging and edible coatings were also examined in preliminary storage trials and showed promise as technologies to maintain fruit and stem quality. However it was the quality of the fruit delivered to the store that was more important than changes that are occurring once fruit is placed on display. The quality issues identified require additional investigation to facilitate improvement and highlight the challenges of meeting consumer expectations consistently, including during periods of peak volume and unfavourable growing conditions.

Technical summary

Two surveys of cherry fruit quality were conducted during the 2010/11 and 2011/12 seasons in selected representative retail stores in Sydney and Adelaide. Fruit quality was assessed using the same quality criteria at both the Gosford Primary Industries Institute (NSW) and at the South Australian Research and Development Institute (SA). Fruit quality was assessed by determining the percentage of rots, fruit defects and overall consumer acceptability. On a sub-sample of fruit; the condition of the stem, fruit colour (‘Australian Cherry Colour Chart’), fruit size, stem pull force, fruit firmness (FirmTech), TSS (total soluble solids) and TA (titratable acidity) were also measured. An over-riding observation was the high level of unacceptable fruit on the market in both seasons. The average level of unacceptable fruit (as determined by defects and rots, rather than consumer taste testing) across both seasons was 11%. In the 2010/11 season, this level of unacceptable fruit was consistent across the entire season, whilst in the 2011/12 season there were some lines with very high levels of unacceptable fruit and many good quality lines. This was assessed from 50 fruit subsamples of each fruit sample purchased from each store. The main reasons for the unacceptable fruit were pitting, bruising and rots. These three reasons accounted for over ⅔ of all the major defects observed across both seasons. Similarly, pitting and bruising were also responsible for ⅔ of the level of minor defects. These levels of defects are well above the acceptable limits of defects and need to be addressed. Some poor out-turns were followed back through the supply chain and these issues were rectified. The identification of pitting, bruising and rots as the most important quality issues at the retail level was not entirely surprising as these defect types are not readily identified or removed during the packing process. In addition, these defects frequently develop or progress after the fruit has been packed. A preliminary packing line survey of seven different cherry packing lines was conducted in NSW and SA in the 2011/12 season. Fruit from different sampling points from the orchard to the packed box were sampled and stored to assess for defects. The results of this preliminary survey showed there were key points in the packing line which require attention to minimise these defects. The cluster cutter and the final sorting / packing line were significant areas which need improvement. Although impact damage is a significant factor in pitting, more work is required to quantify this and identify other factors which need to be managed to improve fruit quality to the consumer. In general, the level of fruit sugars (TSS) in the 2010/11 season was low and reflected the poor growing season. However in the 2011/12 season, fruit TSS was improved. Fruit TSS content of 15°Brix or higher is generally satisfactory for consumer acceptability and this limit is often a commercial standard. The results of the 2010/11 survey showed that although the average of all TSS measurements was 15°Brix, 54% of fruit samples had an average TSS of less than 15°Brix. However there were some sweeter lines of fruit sampled during the season. In the 2011/12 season, only 19% of all samples were less that the 15°Brix. However inconsistent

5 eating experiences, such as those caused by low and inconsistent TSS fruit will have significant impacts on consumer acceptability and repeat purchases of cherries. The addition of a one week storage period at 5oC on selected fruit from NSW in the 2010/11 season showed a significant increase in the levels of unacceptable fruit following storage. In this study, the average level of unacceptable fruit increased three fold following storage. The progression of storage rots was the main contributor to the increase in unacceptable fruit when fruit was stored after purchase from the retailer. Pitting and bruising were also significant major and minor defects across the entire season at purchase and during storage. Indeed, these three defects (major and minor) accounted for over 87% of all defects across the season and during storage. Observations in the retail store showed that significant deterioration in product quality does occur while the fruit is on retail display. The most obvious and consistent difference between samples observed out of the cool room (freshly delivered) and from the retail display was in stem quality, specifically stem browning. Stems of fruit sampled from the retail display were browner and appeared dehydrated compared to fruit sampled from the cool room. In addition, fruit bruising at the retail level was also a significant issue which needs to be addressed. Less obvious differences occurred in the firmness, colour and size of fruit. Observations in this survey indicate that factors prior to fruit being placed on retail display are more important for these quality parameters than changes that are occurring once fruit is placed on display. However the significant deterioration in stem condition warrants addressing at the retail level. A series of stem quality experiments were conducted and showed that the storage and display environments have a significant effect on stem condition. Storage environments with low relative humidity, high air flow rates around the fruit and higher temperatures significantly result in browner and less fresh stems. The use of packaging to optimise fruit quality was assessed in a preliminary trial and showed the benefits of packaging, especially in the higher display temperature environments. The potential use of edible coatings and films was assessed and show some promise to maintain stem quality and minimise water loss. Different types of retail display in supermarket and a small independent fruit and vegetable store were quantified and showed that there where large variants in temperature and relative humidity in the display which can impact on fruit quality. It was also found that it is important not to assume the static conditions of the retail display as large changes in temperature and relative humidity were observed over the day. The specialised refrigerated table was the best display presentation as it maintained low display temperatures and high relative humidities around the fruit. The quality issues identified require additional investigation to facilitate improvement and highlight the challenges of meeting consumer expectations consistently, including during periods of peak volume and unfavourable growing conditions.

1. Introduction

Issues of poor fruit quality and excessive shrinkage (waste) in the cherry market were identified as important issues in previous seasons. The domestic market consumes 80% of the total Australian cherry production and problems with inconsistent quality can significantly depress the local market in times of high supply. Poor eating experiences can delay further repeat purchases of cherries, particularly when other attractive summerfruit (peaches and nectarines), grapes, berries and mangoes are also in the market at this time. Occasional but significant inconsistent out-turn of Australian cherries not only causes large short term commercial loses, but more importantly results in loss of confidence in the entire cherry industry. Any loss of confidence in the product results in further delays in sales at the retail and wholesale level, thus increasing the extent of the problem. Fruit quality has remained a significant issue for the cherry industry since the 2008/09 season, when retailers highlighted the severity of the issue to the cherry industry. Though the issues have been acknowledged by the industry anecdotally, the extent, exact nature and most likely causes of the problems have not been quantified, or rectified. This project was set up in the first instance to obtain a baseline data set on fruit quality arriving at supermarkets and on retail display. Documentation and analysis of this data set will provide a platform from which the industry can develop strategies to address the identified and quantified shortcomings in quality. In the longer term the data generated will provide critical information towards preparing a matrix to predict the quality and storage life of Australian cherries, depending on their initial quality at harvest. These systems are being implemented by the Chilean cherry industry, increasing their competitiveness in export markets that the Australian industry wishes to access (Zoffoli, 2009). This was an industry driven project which was conducted in the 2010/11 and 2011/12 cherry seasons (November to February). Both the 2010/11 and 2011/12 cherry seasons were challenging years for growers to produce consistently high quality fruit due to the high and consistent levels of rain just before and during harvest. The major cherry growing areas of Young (NSW), Adelaide Hills (SA) and throughout Victoria and Tasmania were all affected in both growing seasons by significant rainfall during summer. For example, the Young growing district in NSW normally receives 98mm during the November and December harvest season (Bureau of Meteorology), but in the 2010 season the Young district received 452mm of rain during November and December harvest period. This unusually high level of rain was a challenge to maintain fruit quality due to soft fruit, splits and rots.

2. Fruit Quality Survey 2.1 Retail Survey

Materials and Methods

Survey timing and locations The retail survey of fruit quality was assessed in two seasons; 2010/11 and 2011/12. 2010/11 Fruit Quality Survey (Year 1) The survey of cherry fruit quality was conducted during the 2010/11 season in selected representative Woolworths stores. Planning meetings at Woolworths on 16 November 2010 resulted in selecting three stores in western Sydney (Seven Hills, Blacktown and Rouse Hill) and three stores in Adelaide (Kilkenny, Findon and Tea Tree Plaza). These stores had an average turnover and typical demographic of Western Sydney and Adelaide respectively. In NSW, fruit sampling was conducted from 26 November 2010 until 3 March 2011 and in SA from 14 December 2010 until 15 February 2011. Woolworths gave their full cooperation with this project and allowed access to their Distribution Centres, retail stores and produce coolrooms in the back of their retail stores. 2011/12 Fruit Quality Survey (Year 2) The survey of cherry fruit quality was conducted during the 2011/12 season in selected representative retail stores. The weekly survey occurred in four stores (including independent stores) in Adelaide and two supermarkets in NSW. Adelaide stores were selected to overlap with the concurrent category management program 2011/12 (CY 11024). Stores selected included four from Adelaide’s North Eastern and Eastern suburbs (Woolworths Tea Tree Plaza, Woolworths Marryatville, Coles Firle and Tony & Mark’s at Newton) and two stores in NSW, were from the Central Coast (Woolworths Bateau Bay and Woolworths Tuggerah). In SA, fruit sampling was conducted from 29 November 2011 until 14 February 2012, while in NSW fruit sampling was conducted from 1 December 2011 until 16 February 2012. All companies gave their full cooperation with this project and allowed access to their retail stores.

Fruit sampling 2010/11 Fruit Quality Survey (Year 1) Fruit were sampled from the six representative stores at weekly intervals (every Thursday) in NSW and twice weekly in SA (every Tuesday and Friday). Samples were purchased from the front of the retail display and where possible from the back cool room in the store. Fruit was purchased from the retail display or opened cartons

8 with no selection or sorting of the fruit done at this stage. Fruit from the receiving area of the store was normally delivered that morning from the Distribution Centre. Each sample of 0.8 - 1kg of fruit was placed in a standard retail polyethylene bag. All fruit were immediately transported to the assessment sites in an insulated container (esky) and assessed for quality at 20˚C on arrival. Additional fruit (2-3 kg) was purchased from the back coolrooms in the NSW stores for shelf life testing. All relevant fruit information (variety, size etc) were recorded in-store. 2011/12 Fruit Quality Survey (Year 2) Fruit were sampled from the four representative stores at weekly intervals, every Tuesday in SA and every Thursday in NSW. Samples were purchased from the front of the retail display in the store. Fruit was purchased from the retail display or opened cartons with no selection or sorting of the fruit done at this stage. Each sample of 0.8 to 1kg of fruit was placed in a standard retail polyethylene bag. All fruit were immediately transported to the assessment sites in an insulated container (esky) and assessed for quality at room temperature (20˚C) on arrival. All relevant fruit information (variety, size etc) if available, was recorded in-store.

Fruit quality assessment The assessments for fruit quality were conducted using the same quality assessment criteria at both the Gosford Primary Industries Institute (NSW) and the South Australian Research and Development Institute (SA). Fruit was examined and divided into acceptable and unacceptable fruit as might be done by a consumer selectively, but very quickly picking fruit from the display. Only fruit that would clearly not be consumed, i.e. obvious rots or physically damaged fruit was considered unacceptable. Fruit without stems were considered acceptable. The percentage of unacceptable fruit was determined from the weight of acceptable and unacceptable fruit for each sample. These fruit samples were then recombined before two subsamples of fruit were taken. One set of samples (50 fruit) was placed at room temperature (20°C) for immediate quality assessment, with the other set of samples (25 fruit) sealed in plastic bags, frozen and held at -18°C for later me asurement of titratable acidity level. Of the subsample of 50 individual fruit held at 20°C, twenty four different defect types (stem and nose cracks, bruising, rots, insect damage etc), were assessed according to the ‘Australian Cherry Quality Guide’ (2004). In addition, the number of stemless fruit in the 50 fruit sample was recorded. On the first 25 fruit assessed for defects, the following quality parameters were measured; - Average fruit diameter (mm) determined by the minimum diameter hole through which individual cherries would not pass on the sizing plates attached to the Australian Cherry Colour Guide - Fruit skin colour (rating scale) by comparing against colour plates of the Australian Cherry Colour Guide

- Fruit firmness (g/mm) with a FirmTech instrument. - Stem pull force (g) required to detach the stem from the fruit using a digital gauge (Lutron FG-5005) fitted with a custom built fruit holder. - Stem colour (visual score) according to rating scale (Figure 1). - Subjective fruit flavour (score) according to rating scale; 1 = excellent flavour, 2 = good flavour, 3 = acceptable flavour, 4 = little flavour / unacceptable, and 5 = lacks flavour / no flavour. (10 fruit per sample individually tested and scored) - Total soluble solids (°Brix) measured by expressin g juice of each fruit that had been flavour tested onto the measuring prism of digital refractometer

Rating Description

1 Bright green

2 < 10 %

3 10 – 25 %

4 > 25 %

Figure 1. Subjective rating scales for stem browning

Fruit that was stored at -18oC was defrosted immediately prior to testing. As soon as fruit reached room temperature (20°C) a composite j uice sample was obtained and tested as follows; Total titratable acidity (expressed as g/100mL malic acid equivalent) was determined on 10mL juice samples (diluted with 10mL of RO water) by titrating to an endpoint of pH 8.2 with 0.1 N NaOH using an automatic titrator.

Testing of shelf / consumer life To investigate the shelf-life / consumer life of the fruit, a sample of fruit taken from the back cool room of the retail stores was stored for an additional one week at 5oC before a final assessment of fruit quality was conducted during the 2010/11 season in NSW. Fruit was held in the standard polyethylene retail bags in which the fruit was purchased. This storage time and temperature combination was chosen as the maximum storage period for the consumer. At the completion of the storage period fruit quality assessment was repeated using the same methodology as on the day the fruit were originally purchased.

Data presentation and analysis Data from the survey were compiled into single values for each sample by time, store and sampling position. Where data were collected for individual fruit, such as quantitative measurements and subjective rating scores the data were averaged for each sample collected from the stores. Where data comprised a count from a subsample, the data were expressed as a percentage for each sample collected from the stores. Data on fruit quality are primarily presented to show individual sample values across the sampling period with the individual samples categorised by the retail store they were collected from. Data on the incidence of defects are presented as single percentages across the whole season, with only the most common defects presented to show variation throughout the season. Where appropriate the results of the survey have been benchmarked against industry quality standards. Based on the performance against these standards comments have been made on the implications for industry, key factors that influence and indication of strategies to improve. Comparisons have been made between samples on the basis of their origin where it was feasible to do so. Samples taken from the retail display and the back cool room were compared, as were samples of different varieties and samples from different stores. Statistical analysis was not used to compare the survey data, as the samples are not directly comparable. Correlations tend to be weak in this type of survey data due to the high number of variables that impact on any given quality trait of an individual sample. Where logical to do so the correlation between measurements has been presented. These include the relationships between total soluble solids, titratable acidity and subjective flavour scores, and the relationship between stem loss and stem pull force within the survey data. In the 2010/11 season, comparisons of matched samples of fruit sampled immediately from the store and after one week storage at 5˚C were made at Gosford Primary Industries Institute.

Results and Discussion The survey of fruit quality was conducted throughout two cherry seasons (2010/11 and 2011/12). In the 2010/11 season a total of six supermarket stores in Adelaide and the Sydney were surveyed, whilst in the 2011/12 season, six retail stores were surveyed, but the scope of the survey was widened to include both independent stores and supermarkets in the 2011/12 season. A comprehensive assessment of cherry quality was conducted on this fruit including both quantitative and subjective measures. The main focus of this project was to appraise the quality of fruit reaching the consumer, identify any shortfalls in this quality against industry benchmarks and to highlight areas of concern. Providing detailed strategies to overcome these issues is beyond the scope of this initial study; however key practices and or avenues to improve performance are indicated. Quality of the fruit was assessed utilising the Australian Cherry Quality Guide. Where possible the quality of the fruit has been benchmarked against the standards set out in this guide. This illustrated guide was developed with the Australian industry and has wide applicability to the range of markets to which the Australian industry is selling cherries. Individual markets often set their own standards for quality and in some cases these vary from those set out in the Australian Cherry Quality Guide. In some instances fruit quality in this report is also discussed with reference to other benchmarks that have been established in the market place.

Visual appearance of fruit Visual appearance of the fruit and the stem are important market criteria for cherry fruit. Assessment of visual appeal is subjective and has been conducted using the grading standards set out in the Australian Cherry Quality Guide along with the additional rating scales for stem quality and overall acceptability.

Acceptability of fruit (rots and defects only)

Visual appearance of fruit Visual appearance of fruit over the 2010/11 season Fruit was visually examined and the number of fruit that were obviously unacceptable counted out of 50 fruit of each sample collected. This was done by quickly sorting fruit for major defects as might be done by a shopper at a supermarket. In this assessment fruit without stems were still considered acceptable. Across the entire 2010/11 season and in both states, an average of 11% of all fruit examined in this way was considered unacceptable (Figure 2). The number of unacceptable fruit varied substantially between individual lots of fruit. An example of this is presented in Figure 3 which shows that although the average number of fruit in week 10 (starting 24 January 2011) was 11% unacceptable, the average unacceptable levels of the individual samples from the different stores / samples during this week ranged from 0 to 48%. These results indicate that consumers were frequently confronted with retail displays of cherries where there was a substantial

12 number of visually unacceptable fruit. A more detailed examination was then conducted on the fruit to define the nature of both major and minor defects.

10 Unacceptable (%) Unacceptable

0 1 2 3 4 5 6 7 8 9 1011121314 Week fruit sampled

Figure 2. Average percentage of fruit that were considered unacceptable in each week from samples purchased from six stores (three in NSW and three in SA) over the 14 week sampling period of the 2010/11 season.

20 % Unacceptable 10

3 1 1 2 2 3 3 W 1 W 2 W 3 A A A A A A S SA 1 SA 1 S S SA 2 SA 2 S S SA 3 SA 3 S S e = 11 NS N NSW 2 NSW NS g ra ve A Store fruit sampled from

Figure 3. Average percentage of fruit that were considered unacceptable in individual samples purchased from six stores (three in NSW and three in SA) in week 10 (ie. starting 24 Jan 2011) of the survey. The average percentage of unacceptable fruit in this week was 11% and the last bar on the right represents this average.

Visual appearance of fruit over the 2011/12 season Across the 2011/12 season and in both states, slightly less than 11% of all fruit examined was considered unacceptable (Figure 4). This was similar to the 2010/2011 season (Figure 2) however unlike last season where consistent numbers of unacceptable fruit were observed over the season, the number of unacceptable fruit in the 2011/2012 season decreased considerably in the second half of the season (<5% unacceptable fruit from Week 7 to 12). These results indicate that consumers were confronted with retail displays that had the highest percentage of unacceptable fruit (between 19 and 26%) present between Week 1 (the week beginning the 28th November 2011, the first week of sampling), and Week 5 (26th December 2011, the week immediately after Christmas) and 6 (beginning 2 January 2012 the week of trade after New Year) (Figure 4). This is a very important time for cherries and is a concern.

Figure 4. Average percentage of fruit that were considered unacceptable in each week from samples purchased from six stores (two in NSW and four in SA) over the 12 week sampling period in the 2011/12 season. The “Ave” column is the average unacceptable fruit observed over the entire 2011/2012 season.

The results presented in Figure 4 show that 27% of fruit collected in Week 1 was considered unacceptable. The individual store figures for Week 1 (Figure 5) show only one of the stores sampled had an unacceptable cherry percentage of an extremely high 74%, while all other stores sampled remained at or below 12% unacceptable fruit. The high quantities of unacceptable fruit present in the NSW 1 retail display should have been evident to store staff and removed before placing on the retail display or when tending to the display throughout the day. Figure 5 shows the average percentage of fruit that was considered unacceptable from all stores over the 12 week sampling period in 2011/12 and shows the number of unacceptable fruit varied substantially between stores.

Figure 5. Average percentage of fruit that were considered unacceptable in each week from samples purchased from the six stores over the 12 week sampling period in the 2011/12 season. (Note: there are missing samples for SA 1 in Week 7, SA 2 in Week 5 and 12, SA 4 in Week 1 and NSW 2 in Week 11). The absence of data for some stores indicates that there were 0% unacceptable cherries on those weeks.

Defects Fruit were individually examined for defects using the grading standards set out in the Australian Cherry Quality Guide along with the additional rating scales for stem quality and overall acceptability listed. As expected, close examination of individual fruit revealed a higher level of defect identification than the broad consumer litmus type test applied when assessing overall acceptability of the fruit in the previous section. This higher level of identified defects was due to the greater scrutiny of each individual cherry. Fruit defects in the 2010/11 season The results showed that pitting, bruising and rots accounted for 73% of all the major defects whilst pitting and bruising also accounted for 65% of all minor defects in the 2010/11 season (Table 1). Fruit defects in the 2011/12 season Similarly to the 2010/2011 season, the 2011/12 season results showed that pitting, bruising and rots accounted for 77% of all the major defects whilst pitting and bruising also accounted for 69% of all minor defects (Table 2).

The three main defects highlighted, are not readily identified or removed during the packing process. In addition, these defects also frequently develop or progress after

15 the fruit has been packed. Therefore management strategies that address the underlying causes of these defects need to be developed and improvements made to the supply chain to rectify these issues. These aspects were investigated in Section 3. Other defects such as nose cracks, splits etc that were measured tend not to change from the time that the fruit was packed, and therefore should be managed effectively by grading out these defective fruit on the packing line, although as highlighted previously, nose cracks were the fourth largest major defect found, which suggests ineffective grading or rain periods prior to harvest affecting large quantities of the fruit. This does not mean that they are unimportant to industry profitability, as percentage pack out and unit labour requirements for grading are well recognised drivers of profit. However, this study focussed on the quality issues that are present at the retail level.

Table 1. Percentage of fruit surveyed having major and minor defects and breakdown by defect type (Australian Cherry Quality Guide) in the 2010/11 season. Combined data for fruit surveyed from back cool room and retail display of stores.

Level of Incidence Type of defect Breakdown Defect (%) (%)

Major 17.5 Pitting 35.6 Bruising 22.6 Rot 14.8 Wet split 8.1 Nose crack 7.6 Stem crack 4.7 Scarring 3.6 Suture split 2.6 Thrip 0.4

TOTAL 100

Minor 46.0 Pitting 40.5 Bruising 25.0 Scarring 11.5 Nose Crack 5.9 Rot 4.3 Dry Split 2.9 Insect Damage 2.6 Stem Crack 2.0 Overmature or Heat / Soft 1.7 Thrip 1.2 Bird Damage 0.8 Growth Deformity 0.8 Immature 0.7 Double 0.2 Spur 0.0

TOTAL 100

Table 2. Percentage of fruit surveyed having major and minor defects and breakdown by defect type (Australian Cherry Quality Guide) in the 2011/12 season.

Level of Incidence Type of defect Breakdown Defect (%) (%)

Major 17.3 Pitting 34.4 Bruising 27.4 Rot 15.8 Nose crack 7.7 Scarring 3.6 Thrip 3.4 Wet split 3.1 Stem crack 2.6 Suture split 2.0

TOTAL 100

Minor 60.1 Pitting 44.9 Bruising 24.4 Scarring 6.5 Nose Crack 6.3 Rot 4.5 Dry Split 3.3 Thrip 3.2 Insect Damage 2.6 Stem Crack 1.4 Bird Damage 1.2 Overmature or Heat / Soft 1.2 Growth Deformity 0.4 Immature 0.0 Double 0.0 Spur 0.0

TOTAL 100

Pitting Pitting was the most common major defect found on the fruit, accounting for over one third of all major defects in both seasons. High levels (18.6% and 45%) of minor pitting were also present in all fruit over the 2010/11 and 201/12 cherry seasons respectively (Table 1 and 2). Over the two cherry seasons monitored, pitting has been the main defect (of both major and minor) for fresh cherries. Implications for industry Pitting is a serious defect in cherry fruit, it is characterised by the appearance of irregular hardened depressions that can occur anywhere on the fruit (Patten et al., 1983). Pitting detracts from the overall visual appearance of the fruit when on display and when severe detracts from the eating experience of individual fruit. Where a high proportion of the fruit on retail display has pitting it is expected that some sales would be lost. Key factors that influence Pitting is a complex issue with several different types of pitting occurring and numerous factors contributing to its incidence (Facteau, 1982; Patterson, 1987; Wade and Bain, 1980). Previous surveys have linked pitting to physical damage, and pinpointed processes such as harvesting and cluster cutting as major sources of the damage that lead to fruit pitting developing (Thompson et al., 1995). In addition, varietal characteristics and firmness of the fruit influence the susceptibility of fruit to physical damage, and hence the impact on the incidence of pitting. Crisosto (1992) also showed that the incidence of pitting is negatively correlated with high total soluble solids levels. Suggested strategies to improve performance A dual strategy of growing fruit that is less prone to pitting and minimising the level of physical damage to the fruit that occurs postharvest is required. Harvesting and postharvest handling and packing practices need to be continually monitored to ensure physical damage is minimised. Cluster cutters have been identified previously as a major source of damage leading to fruit pitting and require particular attention (Patten et al., 1983). Pitting can only be prevented if the source of the problem is identified. It is suggested that monitoring and follow up assessment of fruit pitting is integrated into QA practises (Kupferman and Sanderson, 2001). As well as good equipment design and product flow, equipment needs to be operated at its optimum speeds and throughput.

Bruising Bruising is the physical damage (compression and compaction) of the cherry fruit flesh (Kupferman and Sanderson, 2001) and was the second most common major defect found on the fruit in both seasons (Table 1 and 2). In the 2010/11 season, bruising accounted for over one fifth of all major defects, whilst in the 2011/12 season, bruising accounted for just under a third of all major defects. High levels

(12%) of minor bruising (12% and 24%) were also present in all fruit over the cherry season in 2010/11 season and 2011/12 season respectively.

Implications for industry Bruised fruit are less visually attractive than sound fruit and are more susceptible to the development of postharvest rots. In addition, if the consumer perception of fruit texture is negative due to bruising, it will affect buying behaviour. For example, when a shopper picks up a bruised fruit and it is soft and mushy, a purchase may be lost. If bruised fruit are purchased, then the fruit will either be later discarded or if eaten it will generally leave the consumer with an off flavour in their mouth to go with the initial disappointment of its lack of texture (crunch). Though most consumers will not notice, the flesh of bruised fruit will also have an unattractive brown colour when bitten into. Therefore minimising the incidence of soft bruised fruit is a key market imperative. Key factors that influence Poor (or the lack) of fruit firmness is a high risk factor for increased bruising incidence. Sound firm cherries that are handled appropriately will not exhibit bruising in the market place. Preharvest, harvest and postharvest practices that compromise fruit firmness will lead to a higher incidence of bruising, which will then be exacerbated as shoppers pick over the fruit at retail level. All processes along the supply chain should be assessed in relation to minimising the risk of physical injury (compression and compaction) and bruising to the cherries. Careful postharvest handling of the fruit from the orchard to the consumer is essential. Even though the fruit may appear sound and free of bruises at the time of packing, the flesh discolouration and softening associated with bruise development can occur during storage, transport and display. Suggested strategies to improve performance Varieties and orchard management practices that produce firm sound fruit will reduce the likelihood of fruit bruising occurring. Orchard practices which encourage the production of firm sound cherries should be encouraged as no amount of care from the point of harvest will improve fruit that is inherently soft to begin with. Harvesting and postharvest handling and packing practices need to be continually monitored to ensure common practices such as fruit transfer, size grading and packing are not contributing to the bruising problem. Where bruising is a problem, it can only be prevented in future if the source of the problem is identified. It is suggested that monitoring and follow up assessment of fruit bruising is integrated in QA practises. As well as good equipment design and product flow, staff need to be appropriately trained in the careful handling of cherries, and the need to avoid damaging practices such as ‘raking’ of the fruit to move it.

Rots Postharvest losses due to fungal decay can occur despite application of fungicides and other recommended procedures. The major rots are brown rot caused by Monilinia spp. and blue mould caused by Penicillium expansum (Crisosto, 1992; Tian et al., 2001). In this survey, rots were the third most common major defect found on the fruit, accounting for approximately 15-16% of all major defects in both seasons (Table 1 and 2).

Implications for industry Rots are particularly damaging to the consumer appeal of cherries. When rots are obvious in a retail display, many consumers will be discouraged from any purchase. Some consumers are loath to touch decayed fruit, let alone buy it or sort through it. In open displays, many consumers are prepared to pick out good fruit, which leaves an even poorer quality selection of fruit behind. Consumers picking over fruit results in an increasing percentage of decayed fruit in the display and also damages other good fruit. The presence of decayed fruit increases the difficulty for the retailer to maintain an attractive display of fruit, requiring more time and effort from the retail store staff in the removal of this fruit. Even when decayed fruit is not obvious at purchase, consumers will be disappointed when the rotten fruit is later discovered after purchase. This disappointment will arise from having to throw out a percentage of cherries when they have deteriorated further, as well as that fruit with less obvious rots are sometimes eaten, leaving the consumer with a strong off-flavour in their mouth. Key factors that influence The incidence of decay is strongly related to weather conditions and orchard management practices early in the season and prior to harvest (Mooney et al., 2011). Cracked and rain damaged fruit is associated with higher levels of decay incidence. Disease management in the orchard which results in low levels of inoculum is the best strategy to minimise decay problems in the postharvest supply chain. That is not to say that practices after harvest are not critical for minimising decay incidence on the fruit. Best practice postharvest temperature management and sanitation are critical, and the use of treatments such as modified atmosphere packaging and fungicides are also useful in reducing disease incidence as fruit moves through the supply chain. Suggested strategies to improve performance Orchard strategies to minimise inoculum level and disease incidence are beyond the scope of this project, but are a key platform from which to achieve improved performance. Important strategies from harvest on include selective picking to minimise the percentage of decayed and cracked fruit entering the packing shed, rapid pickup and pre-cooling of fruit once harvested, prompt and correct use of appropriate sanitisers, minimisation of bruising and physical damage during harvest and handling, maintaining temperature control through supply chain, as well as the correct use of modified atmosphere packaging and fungicides where appropriate.

Fruit quality parameters

Firmness Firmness of the fruit varied considerably between samples and there were no clear patterns of fruit firmness across the season, although there were some periods during the season where fruit firmness trended higher or lower than the average (Figure 6 (2010/11 season) and Figure 7 (2011/12 season)). However there was a significant difference between the two seasons, with fruit in the 2011/12 season were significantly firmer than in the 2010/11 season. Some standard benchmarks for fruit firmness use a 250 g/mm standard with the FirmTech instrument (airfreight transport, Australian Cherry Quality Guide, 2004). If a standard of 250 g/mm was applied across the 2010/11 season then only 79% of the samples have an average firmness that met the standard. This meant that 21% of the total samples (1 in 5 samples) did not meet the 250 g/mm benchmark. However other standards use a 225 g/mm benchmark. If this is applied to the data, then the majority of fruit samples (91%) had an average firmness value above 225 g/mm. This is a relatively pleasing result in a season when firmness was not favoured by rain at or before harvest and poor growing conditions. Periods of rainfall or intense or sustained heat before or at harvest can lead to substantial drops in the cherry firmness. The periods where firmness values of samples tended to dip are associated with rainfall events that occurred in the major supply districts in the preceding week/s. There was a perception by the assessors that fruit was sometimes too soft even though the quantitative measurements made with the FirmTech instrument were above the benchmark. This may be due to: (1) the variability in firmness of individual cherries tasted by the assessors (rather than the average firmness value), (2) other textural properties of the cherries that were not measured with the FirmTech instrument, or (3) that the benchmark or firmness is not high enough. These observations require more investigation. The fruit firmness data over the 2011/12 season shows that if a standard of either 225g/mm or 250 g/mm are applied then only two or three of the samples had an average firmness that did not meet these standards (Figure 6). This means that 97% or 95% of samples respectively, had an average firmness value above the two benchmarks of 225 or 250 g/mm. This result is a significant improvement on the 2010/2011 season where only 79% of cherries met the 250 g/mm standard and 91% met the 225 g/mm standard.

600 NSW 1 NSW 2 500 NSW 3 SA 1 400 SA 2 SA 3 300

200

100

0 Firmtech firmness (g/mm) firmness Firmtech 18/11/2010 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011 Sampling date

Figure 6. Average fruit firmness of individual samples purchased from six stores (three in NSW and three in SA) over a 14 week period. Firmness measured using FirmTech Instrument.

Figure 7. Average fruit firmness of individual samples purchased from six stores (two in NSW and four in SA) over a 12 week period in the 2011/12 season. Firmness measured using FirmTech Instrument.

Implications for industry Fruit firmness is critical to getting a product of high eating quality to the consumer. Most consumers prefer cherries that have a slight crunch when eaten (Kappel et al., 1996). Soft cherries with a mushy texture have an unfavourable impact on the eating experience, irrespective of their flavour. Consumers will tend to avoid buying cherries that are soft when picked up from a retail display. Additionally, soft cherries are prone to bruising and pitting, both of which were found to be prevalent in the samples purchased in this quality survey. Sound firm cherries that are handled appropriately will not exhibit bruising in the market place. Key factors that influence Selecting the correct varieties and growing them using production practices that enhance their firmness and its retention as the fruit moves through the supply chain are key prerequisites for delivering fruit with the desired firmness and eating texture to consumers (Kupferman and Sanderson, 2001). Temperature management is essential to maintain the firmness of cherries as they move through the supply chain. Weather conditions in the period leading up to harvest can have a substantial impact on the firmness of fruit. Firmness of fruit will be reduced by harvesting during hot conditions or late in the day. Suggested strategies to improve performance Choose varieties that have naturally firm fruit and apply orchard management practices that favour production of firm fruit. No amount of care from the point of harvest will improve fruit that is inherently soft to begin with. Prompt pre-cooling after harvest and subsequent best practice temperature management is an important means of retaining the fruit firmness. Fruit should also be harvested at its optimum maturity.

Total Soluble Solids Total Soluble Solids (TSS), also referred to as °Br ix, Brix%, Soluble Solids Content% or SSC%, is a measure of fruit sweetness. In the 2010/11 season, fruit TSS levels varied considerably between samples, with the highest level recorded being 20.4°Brix and the lowest 11.1°Brix (Figure 8). Whil st in the 2011/12 season, the highest level recorded was 22.8°Brix and the lowest 12.3°Brix (Figure 9). Overall the levels of fruit TSS across the 2010/11 season were disappointing; with more than half the samples having an average TSS level of less than the industry benchmark level of 15°Brix. Cherries generally have to have a TSS above 15°Brix to have acceptable flavour (Australian Cherry Quality Guide, 2004). These results indicate that many consumers would have been left unsatisfied by the eating quality of the cherries they purchased in the 2010/11 season. However, overall the levels of fruit TSS across the 2011/12 season were significantly improved; with only 19% of samples having an average TSS level of less than the industry benchmark level of 15°Brix. Interestingly, 38% of those that had a TSS level

24 of <15% were sampled from NSW 2. Cherries generally have to have a TSS above 15°Brix to have acceptable flavour (AFFCO, 2004). These results indicate that many consumers would have been satisfied and in many cases extremely satisfied with the eating quality of the cherries they purchased in the 2011/2012 season, unlike the 2010/2011 season where over half the fruit did not meet the industry benchmark TSS level of 15%. There were some seasonal trends with periods during the 2010/11 season where TSS levels trended higher or lower than the average (Figure 8). The periods where TSS values of samples tended to dip are associated with rainfall events that occurred in the major supply districts in the preceding week/s. Thick cloud cover (lack of full sun) during the final stages of fruit ripening before harvest can also slow the rate of TSS accumulation by the fruit. Rainfall also results in a dilution and or loss of sugars in the fruit. TSS levels indicate that fruit eating quality in the 2010/11 season would have been best in mid January 2011. However in the 2011/12 season, fruit TSS tended to increase as the season developed, although there were high and low TSS fruit at all sampling times.

25 NSW 1 NSW 2 20 NSW 3 SA 1 15 SA 2 SA 3

5 Total Soluble Solids (°Brix) Solids Soluble Total

0 18/11/2010 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011 Sampling date

Figure 8. Average total soluble solids level of individual samples purchased from six stores (thee in NSW and thee in SA) over a 14 week period during the 2010/11 season.

Figure 9. Average total soluble solids level of individual samples purchased from six stores (two in NSW and four in SA) over a 12 week period during the 2011/12 season.

Implications for industry Total soluble solids level is a key driver of consumer acceptability (Dever et al., 1996, Crisosto et al., 2003). Fruit of most commercial varieties that has a TSS level of less than 15°Brix is not regarded as a good flav oured cherry by a consumer. Cherries are marketed as a premium quality fruit and generally purchased as an impulse buy for fresh snacking. Customers purchasing product on this basis expect premium quality product. Many of the fruit samples assessed would not have lived up to these expectations. It is unlikely that marketing alone will sustainably achieve a premium price at high sales volumes when 50% of the product in 2010/11 season falling below of consumer expectations. Key factors that influence Total soluble solids levels are influenced by numerous production practices over which the grower has some (eg orchard management) or full control (eg varieties). However the grower has no control over the weather conditions. Although rain covers are an option for growers, they are expensive and are not totally effective in excessive rain events. Though the industry cannot control the weather, implementing orchard practices and strategies that favour high TSS levels in the fruit will increase the percentage of fruit that has sufficient TSS levels. Suggested strategies to improve performance Some varieties are inherently sweeter than other varieties allowing the possibility of growing fruit that has sufficient sugar levels (Dever et al., 1996). In addition, TSS

26 levels increase during ripening of the fruit (McGlasson et al., 2009), meaning that harvesting fruit at the correct maturity for the variety is imperative to maximising fruit sugar levels. However there is a limit to the quantity of sugar a cherry tree can produce and it is difficult if not impossible to achieve satisfactory TSS levels in fruit harvested off overcropped trees. However orchard management practices such as irrigation, nutrition, management of tree vigour and growing systems can all contribute to improving fruit TSS levels. The industry would benefit from the development of a comprehensive advisory package of practical production target strategies.

Titratable acidity Titratable acidity (TA) is a measure of how acid or sour the fruit tastes. The TA in the fruit sampled across the 2010/11 and the 2011/12 season followed downward trends from the start of the season (0.6-1.2 g/100mL) until the end (0.1-0.5 g/100mL) (Figure 10 and 11). There were some minor deviations in the trend, which coincided with the changes in TSS and were most likely also caused by rainfall events during the season. This indicates a substantial change in the flavour profile of the fruit over the season, especially considering TSS levels did not strongly mirror this trend. As a result, the sugar to acid ratio (TSS/TA) changed substantially as the season progressed (Figure 12 (2010/11 season) and Figure 13 (2011/12 season)). The TSS/TA ratio can be a more accurate measure of acceptability to the consumer for fruit. These data suggest that fruit at the beginning of the season would have had a more tart flavour and fruit at the end of the season was characterised primarily by sweetness. Variety changes during the season would have contributed to this trend, with the Lapins variety that dominates fruit supply from the middle of the season, being a lower acid variety than many of the varieties grown at the beginning of the season. In addition more fruit at the end of the marketing season had been stored, and fruit acidity levels are well known to drop substantially in storage (McGlasson et al., 2009). In contrast sugar levels remain relatively stable in storage (Rettke, 2011). Colour of the fruit sampled also became progressively darker as the season progressed (Figure 20), suggesting that fruit maturity at harvest may also be a factor. However as titratable acidity levels remain relatively stable for most varieties during ripening from Colour Stage 4 to 6, this is unlikely to contribute substantially to the seasonal trend in titratable acidity found. The low titration level recorded from SA 3 during the last week of sampling indicates it may have been stored for a prolonged period as fruit acidity levels are well known to drop substantially in storage (McGlasson et al., 2009). However, packing information taken in store suggests storage was minimal (6 days), therefore it is more likely that the low titratable acid reading was due to preharvest factors such as cold or wet weather conditions (Poll et al., 2003).

1.2 NSW 1 NSW 2 1 NSW 3 SA 1 0.8 SA 2 SA 3 0.6

0.4

0.2 Titratable acidity (g/100mL) acidity Titratable 0 18/11/2010 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011 Sampling date

Figure 10. Average titratable acidity of individual samples purchased from six stores (three in NSW and three in SA) over a 14 week period in the 2010/11 season. Titratable acidity expressed in g/100mL malic acid equivalent.

Figure 11. Average titratable acidity of individual samples purchased from six stores (two in NSW, four in SA) over a 12 week period in the 2011/12 season. Titratable acidity expressed in g/100mL malic acid equivalent.

70 NSW 1 60 NSW 2 NSW 3 50 SA 1 SA 2 40 SA 3

Total soluble solids / Acid ratio Acid solids / soluble Total 0 18/11/2010 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011 Sampling date

Figure 12. Seasonal trend in Total Soluble Solids / Acid ratio of samples purchased from six stores (three in NSW and three in SA) over a 14 week period in the 2010/11 season. Total soluble solids expressed in °Brix and titratable acidity expressed in g/100mL malic acid equivalent.

Figure 13. Seasonal trend in Total Soluble Solids / Acid ratio of samples purchased from six stores (two in NSW, four in SA) over a 12 week period in the 2011/12 season. Total soluble solids expressed in °Brix and titratable acidity expressed in g/100mL malic acid equivalent.

Implications for industry The balance of sweetness and acidity (TSS/TA ratio) is an important factor in consumer satisfaction levels (Crisosto et al., 2003). Fruit with medium to high levels of acidity can be a positive trait, as long as the fruit has sufficient sugar levels to balance the flavour. In the absence of sufficient TSS, fruit having high acidity levels will be sour and have a negative impact on consumer satisfaction. There has been a trend in Australia towards the production of low to medium acidity varieties of cherries. Such varieties, though they may be regarded as bland by some consumers, carry little risk of a strong negative response from consumers. Contrast this to the apricot industry where significant damage to the marketplace has occurred from the prolonged marketing of overly acidic varieties. There has been insufficient sensory or consumer research conducted to ascertain if there are marketing opportunities in Australian or export markets for more strongly flavoured cherries characterised by slightly higher acidities. Key factors that influence Variety is the key determinant in the underlying acidity level of fruit (Dever et al., 1996). In addition, seasonal conditions such as rainfall at harvest can influence TA levels. Suggested strategies to improve performance A greater understanding of the implications of fruit acidity levels on the marketplace is required before any substantial action should be taken. Consumer resistance has been found when certain cherries with distinctive flavours or high acidity have been previously marketed. Industry needs to be wary of establishing large commercial planting of new varieties until their flavour profile has been established as being suitable for the market for which they are being planted (whether low, medium or high acidity). In addition, more work is required on how fruit with different TA levels behave in different supply chains. For example, there is some evidence that suggests that varieties with higher acid levels at harvest have a longer storage life and are more suitable candidates for storage.

Flavour Flavour is one of the most critical aspects of fruit quality, especially for a premium fruit such as cherries. In the 2010/11 season, 53% of the samples were rated as having acceptable flavour or above, indicating almost half of the samples had barely acceptable flavour, lacked flavour or had unacceptable flavour (Figure 14). This clearly demonstrates that in the 2010/11 season, the growing conditions were not conducive to the production of high flavoured (sweet) fruit. This is highlighted by the low number of samples that were rated as having good flavour, with no samples being rated as excellent. These results highlight the difficulty that industry faces in delivering a consistent supply of good flavoured cherries to consumers. However for sales and the industry to grow, consumers must be consistently delivered high quality (and tasting) fruit.

However to counter-balance the poor 2010/11 season, 84% of the samples were rated as having acceptable flavour or above in the 2011/12 season; signifying 16% of the samples had an unacceptable flavour or lacked flavour (Figure 15). This highlights that in the 2011/12 season the growing conditions were conducive to the production of high flavoured (sweet) fruit. This is highlighted by the high number of samples that were rated as having ‘good to excellent’ flavour, particularly in the middle to late end of the season. The differences overall acceptability in flavour in the two seasons (53% acceptable in 2010/11 compared to 84% acceptable in 2011/12 season), illustrates the seasonality of fruit quality and flavour and highlights the importance of growing conditions to the overall flavour of cherries and the difficulty that industry faces in delivering a consistent supply of good flavoured cherries to consumers. However for sales and the industry to grow, consumers must be consistently provided with high quality (and tasting) fruit.

Excellent NSW 1 NSW 2 Good NSW 3 SA 1 SA 2 Acceptable SA 3

Unacceptable Subjective flavour score flavour Subjective No flavour 18/11/2010 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011 Sampling date

Figure 14. Average flavour score of individual samples purchased from six stores (three in NSW and three in SA) over a 14 week period in 2010/11.

Figure 15. Average flavour score of individual samples purchased from six stores (two in NSW and four in SA) over a 12 week period in the 2011/12 season.

The balance of fruit TSS (sugar) and TA (acid) is critical to consumer acceptability. A number of studies have been conducted overseas to determine the TSS level that is required for a cherry to have acceptable flavour, and if this is influenced by acidity of the cherry. Crisosto et al. (2003) found high consumer acceptance for Bing and Brooks cherries when TSS were above 16°Brix without regard to TA acidity in the range 0.5 -1.0%. However when TSS were below 13 and 16°Brix for Bing and Brooks varieties respectively, levels of TA above 0.6% reduced consumer acceptance. In this study, the flavour scores assigned in both NSW and SA showed a strong correlation between flavour rating and TSS level. In SA which had the larger data set because fruit was sampled twice per week, the results suggest a minimum of 16°Brix is required for a cherry to be rated as acceptable (Figure 16). There were only 10 samples that had a titratable acidity level of above 0.6 g/100mL malic acid equivalent, so it is difficult to derive any meaningful conclusions on the impact of high acidities on flavour rating from this study, though results for these 10 samples appeared consistent with cherries of less than 0.6 g/100mL malic acid equivalent. However this was followed up in the 2011/12 season and showed that again the flavour scores assigned in both NSW and SA showed a correlation between flavour rating and TSS level. The results suggest a minimum of 16°Brix is require d for a cherry to be rated as acceptable (Figure 17). Based on the r2 results of 0.61 and 0.51, respectively, TSS and corresponding overall flavour variables are related. Therefore if cherries have a TSS value of over 16˚Brix, they will be expected to receive better flavour scores regardless of their acid content.

Excellent Acidity < 0.6 Acidity > 0.6 Good

Acceptable

Unacceptable Subjectiveflavourscore

No flavour 10 12 14 16 18 20 22

Total soluble solids level (°Brix)

Figure 16. Relationship between subjective flavour rating and total soluble solids level for all samples purchased from three stores in South Australia in 2010/11. (r2 = 0.68 for samples having titratable acidity of less than 0.6 g/100mL)

Figure 17. Relationship between subjective flavour rating and total soluble solids level for all samples purchased from four stores in South Australia.

Implications for industry This survey shows that fruit flavour is strongly influenced by growing season. In the 2010/11 season, almost half fruit surveyed from the retail market had barely acceptable to unacceptable flavour. It is likely that this would have caused some suppression of demand. It is reasonable to expect that consumers would purchase and eat more cherries more regularly if the flavour and other quality parameters of the cherries are consistently good, if not excellent. Unfortunately there is a lack of quantitative data to support these statements which makes it difficult to estimate the actual impact of poor flavoured fruit on prices and volumes of sales. However in the 2011/12 season, over 80% of the occasions that fruit was purchased, the fruit had acceptable or better flavour. Thus would have likely caused some increase in demand. However, if consumers had a particularly bad experience with a cherry purchase the previous season, this may have an effect on purchases in subsequent seasons. But there are no data to support these statements. Key factors that influence Consistently achieving adequate TSS levels in the fruit is required for the industry to consistently meet consumer expectations of flavour. Unfortunately, the industry cannot control weather conditions; nonetheless there are a range of other strategies that could be considered to improve TSS which have been previously discussed. It is also important that the varieties grown for a particular market have the flavour profile that meets the consumer preference in this market. Suggested strategies to improve performance There is a need to quantify the impact varying flavour profiles have on price and volume of sales. It will then be possible to determine and implement strategies to lift the quality of cherries placed on the market above the minimum thresholds. The challenge of achieving this in the Australian cherry industry is substantial.

Size As expected, overall fruit size at the start of the 2010/11 season was on the lower end of the desired range for cherries (24-26mm) but trended upwards as the season progressed ending with the majority of fruit in the range 26-28mm (Figure 18). In the 2011/12 season, again the fruit were at the lower end of the desired range for cherries (24-27mm) at the start of the season, but fruit size trended upwards towards the Christmas period (24-29mm), although this did depend on the store. There seemed to be a more consistent size trend upwards between stores in the latter weeks of the 2011/12 season (26-29mm), with the season ending on a slight dip in size during the final two weeks (Figure 19).

30 NSW 1 NSW 2 28 NSW 3 SA 1 SA 2 26 SA 3

Fruit size size (mm) Fruit 24

20 18/11/2010 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011

Sampling date

Figure 18. Average fruit size of individual samples purchased from six stores (three in NSW and three in SA) over a 14 week period in 2010/11. Fruit size measured using the size grading holes of the Australian Cherry Colour Guide.

Figure 19. Average fruit size of individual samples purchased from six stores (two in NSW and four in SA) over a 12 week period in 2011/12. Fruit size measured using the size grading holes of the Australian Cherry Colour Guide.

Colour The skin colour of the fruit became darker in both seasons (2010/11 and 2011/12) as the season progressed (Figure 20 and Figure 21). At the start of the season fruit colour was mostly between Colour Grade 3 and 4 in the 2010 season and Colour Grade 3 and 6 in the 2011/12 season as assessed using the Australian Cherry Colour Guide. Colour of the fruit gradually increased and by the end of the season most of the fruit was assessed as being as dark as or darker than Colour Grade of 6. This is a substantial shift in the colour of fruit over the season, from fire engine red (Grade 3) to dark mahogany (Grade 6) and black (Grade 7). A number of factors would have contributed to these results including; early season fruit from the early growing areas are inherently lighter red and there is a tendency to harvest fruit as early as possible at the beginning of the season. In addition, the majority of fruit on the market late in the season being out of storage, and the majority of fruit late in the season being of the Lapins variety which is a darker coloured cherry at optimum maturity than many of the early season varieties. There is no real benchmark for colour of cherries as the optimum colour varies with the variety, the market and the individual consumer. There was however, considerable colour variability within some of the samples purchased, especially in the early weeks of sampling, where a wide range of fruit colours ranging between Grade 3 to Grade 6 within a single retail display. This is characteristic of some varieties which are inherently more variable than other varieties. This detracts from the visual appeal of the cherries on retail display and can lead to consumers picking over the fruit more than would otherwise be the case.

NSW 1 7 NSW 2 NSW 3 6 SA 1 SA 2 5 SA 3

4 Fruit colour Fruit

1 18/11/2010 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011 Sampling date

Figure 20. Average fruit colour of individual samples purchased from six stores (three in NSW and three in SA) over a 14 week period in the 2010/11 season. Fruit colour assessed using the Australian Cherry Colour Guide. Values recorded in South Australia include additional colour score of 7 for fruit that is black or near black.

Figure 21. Average fruit colour of individual samples purchased from six stores (two in NSW and four in SA) over a 12 week period in the 2011/12 season. Fruit colour assessed using the Australian Cherry Colour Guide. Values recorded in South Australia include additional colour score of 7 for fruit that is black or near black.

Stem quality parameters

Stem colour Stem colour is a key indicator of freshness to consumers. Though stem quality is not necessarily related to the eating quality or appearance of the fruit itself, cherries with green healthy stems are desired by consumers due to their perceived ‘freshness’. A wide range in stem quality was found in the six retail stores, irrespective of the time of the season (Figure 22 (2010/11 season) and Figure 23 (2011/12 season)). In the 2010/11 season, approximately 1/3 of the fruit purchased had excellent stem quality, while a further third had browning of the stems that was visually obvious when fruit was viewed on the retail display. The majority of samples that had poor stem quality were from the retail display, indicating that a substantial proportion of the loss in stem quality was occurring at the store level while the fruit was on retail display. This is discussed in more detail in the ‘Quality at Retail’ Section.

In the 2011/12 season, approximately 19% of the fruit purchased had excellent stem quality or negligible visible stem browning. In the store, SA 2 samples comprised 63% of those with excellent stem quality. The majority of samples that had poor stem quality were from the Stores SA 1, 3 and 4 with between 90-92% samples having noticeable or visually obvious stem browning. Fruit from SA 4 were observed to have nearly 82% of samples with visually obvious stem browning. This may suggest a slow retail turnover rate of cherries on display (generally an open refrigerated display) or poor display management resulting in stems drying out and therefore increased browning. To combat stem drying, minimise retail display sizes, especially post Christmas/New Year or when fruit are not on special, as these are the most likely times cherries are unlikely to be purchased in big quantities by large numbers of consumers.

> 25% NSW 1 NSW 2 NSW 3 SA 1 10-25% SA 2 SA 3

<10% Stem browning Stem

Green 18/11/10 8/12/10 28/12/10 17/01/11 6/02/11 26/02/11 Sampling date

Figure 22. Average stem browning scores of individual samples purchased from six stores (three in NSW and three in SA) over a 14 week period in 2010/11. Stem browning scores in the upper third of the figure equate to visually obvious poor stem quality, while the middle third have noticeable stem browning.

Figure 23. Average stem browning scores of individual samples purchased from six (two in NSW and four in SA) over a 12 week period in 2011/12. Stem browning scores in the upper third of the figure equate to visually obvious poor stem quality, while the middle third have noticeable stem browning.

Implications for industry This survey indicates that a high percentage of the samples on retail display have visually obvious browning of the stems. This level of poor quality stems would be deleteriously impacting on the consumer view of the products freshness, which is an important factor in a consumer’s purchasing decisions. Key factors that influence Temperature management and the prevention of moisture loss from the point of harvest are the key factors in the preservation of stem quality. Variety and weather conditions leading up to and at the time of harvest also have an influence. In addition orchard pests such as earwigs can significantly affect stem quality in the orchard. Suggested strategies to improve performance The practices required to maintain stem quality at the orchard, packing shed and through the supply chain are well known. Orchard control of stem damaging pests such as earwigs can significantly affect stem quality, but these damaged stems can be identified and graded out at the packing line. Other standard practices include harvesting early in the morning or during cool weather, prompt hydro-cooling and subsequent correct and continuous temperature management in association with the use of moisture barrier bags or modified atmosphere bags. The results in this survey suggest that emphasis needs to be placed on processes to maintain stem quality at the retail level, with large refrigerated displays and a slow turnover rate of cherries allowing stems to dry out quickly due to the extended shopping hours and therefore time on display under a low humidity rather than in cold storage.

Stem loss and stem pull force Australian cherry consumers prefer cherry fruit from an open retail display with their green fresh stems attached. In this study stem loss from samples purchased from the stores varied from none in 15% of cases up to a maximum of 44% in two cases (Figure 24 (season 2010/11) and Figure 25 (season 2011/12)). Both of these cases occurred after either a Christmas or New Year break in the shopping cycle in 2011/12 season, with one of the cases being an open display (not refrigerated) and both displays were of larger than normal quantities, where the turnover rate may not have warranted such a large display. For example, the general number of boxes on display for SA 3 was normally recorded as between two to four boxes at a time, but on this day (27 December 2011) twelve boxes were being displayed. Similarly, one to four boxes were generally observed on display at one time for SA 4, but seven boxes were on display when the sample with the high percentage of stemless fruit was taken (3 January 2012). In 70% of the samples across the 2011/12 season, stem loss at the retail level was 10% or less, whilst in the 2010/11 season, 58% of the samples across the season, stem loss at the retail level was 10% or less. This still leaves 30% (and 42%) of samples that have substantial and obvious stem loss. There was a trend towards higher stem losses at the end of the season. This may be a consequence of reduced stem retention from late season districts and or may have been exacerbated by storage of fruit prior to sale late in the marketing season. This trend of greater stem loss late in the season coincided with a trend for lower stem pull forces (Figure 26). Over the entire season there was a weak relationship between stem loss and stem pull force as measured on the day samples were purchased from stores (Figure 28 (2010/11 season) and Figure 29 (2011/12 season)). These data indicate that little stem loss would be expected on cherry fruit that has an average stem pull force of greater than 500g. This concurs with the figure accepted by industry as target force for stem pull force. However in this survey stem pull force was measured on fruit at the end of the supply chain. As stem pull force drops in storage, the cherries would be expected to have had substantially higher stem pull forces if they had been measured in the orchard at harvest. In addition, the data suggest that high stem pull forces, though they may favour less stem loss, are not essential for achieving low or no loss of stems. For example only an 8% stem loss was recorded from a sample that had an average stem pull force of 3.8g and no stem loss was recorded from a sample that had an average stem pull force of 41g. In addition, numerous samples showed no stem loss with stem pull forces in the range 41-300g. This suggests other factors are also important.

70 NSW 1 60 NSW 2 NSW 3 50 SA 1 SA 2 40 SA 3

20 Stem loss (%) loss Stem

0 18/11/2010 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011

Sampling date

Figure 24. Incidence of stem loss as a percentage of cherries in individual samples purchased from six stores (three in NSW and three in SA) over a 14 week period in 2010/11 season.

Figure 25. Incidence of stem loss as a percentage of cherries in individual samples purchased from six stores (two in NSW and four in SA over a 12 week period.

700 NSW 1 600 NSW 2 NSW 3 500 SA 1 SA2 400 SA 3

300

Stem pull force force (g) pull Stem 200

100

0 18/11/2010 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011 Sampling date

Figure 26. Average stem pull force of cherries in individual samples purchased from six stores (three in NSW and three in SA) over a 14 week period in the 2010/11 season.

Figure 27. Average stem pull force of cherries in individual samples purchased from six stores (two in NSW and four in SA) over a 12 week period.

20 Stem loss (%) Stemloss

0 0 100 200 300 400 500 600 700 Stem pull force (g)

Figure 28. Relationship between percentage stem loss and average stem pull force for all samples purchased from six stores (three in NSW and three in SA) over a 14 week period in 2010/11.

50 45 40 35 30 25 SA Data 20

Stem loss (%) loss Stem NSW data 15 10 5 0 0 100 200 300 400 500 600 700 800 Stem Pull Force (g) Figure 29. Relationship between percentage stem loss and average stem pull force for all samples purchased from six stores (two in NSW and four in SA) over a 12 week period in 2011/12 season.

Implications for industry Most consumers expect that cherries will have stems attached to them and the Australian industry places considerable emphasis on achieving a high percentage of cherries retaining their stems through to consumption. Some consumers find cherries that do not have a stem attached unappealing. Consumer research has shown an acceptance of stemless cherries in other overseas markets such as the USA and Spain, however this relates to when they are all marketed stemless. This survey indicates that stem loss is an issue for some fruit lines when they reach the retailer. Key factors that influence There are substantial differences between varieties in their stem retention. Ongoing research is being conducted on orchard management practices that may increase stem retention (HAL CY08003). In addition, weather conditions leading up to and at harvest may also have an impact. It is also likely that temperature management and packing shed operations such as cluster cutting would also impact on stem retention. Suggested strategies to improve performance As the factors behind stem retention are not fully understood, further investigation is required to determine the best strategies to improve the levels of stem retention.

2.2 Analysis of the surveyed fruit

Analysis of the surveyed fruit in the 2010/11 season Where possible the details of the fruit were recorded from each carton. This was not always possible as sometimes the lids of the cartons had been removed or different lines of fruit had been mixed in the one display. This was especially the case for fruit on retail display. Of the 103 samples examined on retail display in the 2010/11 season, details were obtained on 59 cartons (57% of samples). Of the 64 samples examined out of the stores coolrooms, details were obtained on 60 cartons (94% of samples). In the 2010/11 season, fruit sampled in NSW stores originated from 11 different suppliers, while fruit sampled in SA originated from seven different suppliers. Based on the details on cartons fruit from a wide cross section of growing regions was sampled from Victoria, Tasmania and South Australia. Fruit originating from NSW was also sampled, though inclement weather at harvest meant that samples from the Young growing district were under-represented in this survey.

Variety In total during the 2010/11 season, fruit of 21 varieties were sampled with 13 varieties sampled in NSW and 14 varieties in SA. Even though a high number of varieties were found at the retail level, Lapins accounted for 56 percent of the fruit sampled; reflecting the industries previously reported heavy reliance on this variety (Hansen, 2005) (Table 3). A further 6% were Simone which is a very similar variety. All other varieties made up 6% or less of the samples assessed. Breakdown of the varieties may have been altered if fruit from the Young district was not impacted so heavily by rain damage, for instance a higher percentage of Rons may have been sampled.

Table 3. Summary of the number of samples of each variety purchased from six stores in the 2010/11 fruit quality survey

Variety Number samples

Lapins 66 Sequoia 6 Simone 6 Stella 6 Rons 5 Van 4 Bing 3 Merchant 3 Sylvia 3 Brooks 2 Kordia 2 Regina 2 Sir Doug 2 Vista 2 Chelan 1 Royal Dawn 1 Sir Don 1 Sweet Georgia 1 Sweetheart 1 Tieton 1

The low number of samples of varieties other than Lapins makes it difficult to meaningfully compare the performance of individual varieties. For this reason the survey results from Lapins were compared against the average of other varieties and to four other varieties which had three or more samples taken from either the cool store or the retail display (ie Simone, Sequoia, Stella and Rons). This is presented in Table 4.

Table 4. Comparison of average fruit and stem quality of Lapins with the average of all other varieties in the 2010/11 survey, and to Simone, Sequoia, Stella and Rons cherry fruit.

Parameter Lapins Other Simone Sequoia Stella Rons varieties

Sampled from back cool room of surveyed stores

Number samples 33 30 3 2 3 2

Fruit colour 5.5 4.7 5.7 3.3 5.1 5.0 Fruit size (mm) 25.7 25.6 25.6 - 24.4 25.8 Fruit firmness (g) 333 290 236 295 284 270 TSS (°Brix) 15.7 15.4 15.0 15.3 14.7 15.9 Titratable acidity 0.42 0.54 0.35 0.73 0.46 0.65 Flavour 3.2 3.1 3.8 2.8 3.2 3.6 Stem browning 1.8 1.8 1.2 2.3 1.3 1.4 Stem loss (%) 10 15 3 - 3 8 Stem pull force (g) 163 285 290 162 365 424 Major pitting (% fruit) 9 2 2 - 1 2 Major bruising (% fruit) 4 2 4 - 2 3 Major rots (%fruit) 2 3 0 - 1 4 Minor pitting (% fruit) 25 20 37 - 15 21 Minor bruising (% fruit) 16 11 34 - 7 1 Unacceptable (% fruit) 9 10 3 - 10 14

Sampled from retail display of surveyed stores

Number samples 32 24 3 4 3 3

Fruit colour 5.4 4.8 6.1 3.6 5.1 5.1 Fruit size (mm) 25.5 25.3 25.2 25.7 25.7 25.0 Fruit firmness (g) 303 258 242 264 256 224 TSS (°Brix) 15.4 14.8 14.8 14.6 15.2 15.4 Titratable acidity 0.46 0.55 0.35 0.62 0.53 0.67 Flavour 3.0 3.2 3.6 3.2 2.9 3.4 Stem browning 2.7 2.7 3.6 2.6 1.7 2.8 Stem loss (%) 11 13 10 27 6 7 Stem pull force (g) 168 222 127 173 274 274 Major pitting (% fruit) 8 7 8 5 0 7 Major bruising (% fruit) 6 6 11 6 2 11 Major rots (%fruit) 2 3 2 3 1 8 Minor pitting (% fruit) 19 17 19 4 12 18 Minor bruising (% fruit) 13 9 15 1 5 11 Unacceptable (% fruit) 12 17 10 23 9 31

Analysis of the surveyed fruit in the 2011/12 season Where possible the details of the fruit were recorded from each carton. This was not always possible as sometimes the lids of the cartons had been removed or different lines of fruit had been mixed in the one display. Of the 68 samples examined on retail display in the 2011/2 season, details (full or partial details, had to include variety to be counted) were obtained on 53 cartons (78% of samples). Fruit sampled in NSW stores originated from 9 different suppliers, while fruit sampled in SA originated from 11 different suppliers. Based on the details on cartons fruit from a wide cross-section of growing regions were sampled from New South Wales, Victoria, Tasmania and South Australia. Variety In the 2011/12 season, a total fruit of varieties were sampled in NSW and 13 varieties were sampled in SA. Even though a high number of varieties were found at the retail level, Lapins and Stella varieties accounted for 27 and 17 percent of the known cherry varieties sampled, respectively (Table 5).

Table 5. Breakdown of the number of samples of each variety purchased from four stores in the 2011/12 survey z

Variety Number samples

Lapins 14 Stella 9 Sweetheart 6 Kordia 4 Sweet Georgia 4 Bing 4 Rons 2 Chelan 2 Van 2 Regina 2 Sir Don 1 Sylvia 1 Summit 1 Staccato 1 Z Note: These are the known varieties only, some samples had missing information on their box or box lid information was not able to be recovered

The low number of samples of varieties other than Lapins makes it difficult to compare the performance of individual varieties. For this reason the survey results in the 201/12 season from Lapins were compared against the average of other varieties and to four other varieties which had three or more samples taken from the retail display (ie Sweetheart, Kordia, Sweet Georgia and Bing). This is presented in Table 6.

Table 6. Comparison of average fruit and stem quality of Lapins with the average of all other known and unknown varieties in the 2011/12 survey, and to Stella, Sweetheart, Kordia, Sweet Georgia and Bing.

Parameter Lapins Stella Sweetheart Kordia Sweet Bing Other Other Georgia known Unknown varieties varieties

Sampled from retail display of surveyed stores

Number 14 9 6 4 4 4 12 15 samples

Fruit colour 5.9 5.7 5.8 6.6 5.7 5.2 5.8 5.5 Fruit size 26.6 27.0 26.1 26.2 27.9 24.9 26.1 26.1 (mm) Fruit firmness 351.4 296.1 366.1 279.9 337.0 256.1 341.7 339.6 (g) TSS (°Brix) 18.9 17.4 17.3 19.2 18.1 14.0 17.6 16.9 Titratable 0.5 0.7 0.5 0.7 0.5 0.6 0.7 0.5 acidity (g/100mL) Flavour 2.0 2.4 2.4 2.1 1.8 3.5 2.5 2.4 Stem 2.9 2.7 3.2 3.6 2.8 2.9 2.4 3.1 browning Stem loss (%) 15.3 8.0 6.7 6.0 6.0 6.5 4.0 11.9 Stem pull 158.2 182.5 160.2 171.4 87.3 165.9 334.8 147.3 force (g) Major pitting 7.4 4.9 13.7 10.0 0.5 1.0 1.3 7.5 (% fruit) Major bruising 6.3 4.2 5.0 14.0 1.5 2.0 4.8 2.5 (% fruit) Major rots 2.0 0.4 1.3 0.5 1.0 5.5 0.8 7.2 (%fruit) Minor pitting 29.6 26.3 32.7 31.0 33.0 26.5 25.8 21.2 (% fruit) Minor bruising 14.9 15.8 10.0 21.0 14.0 14.5 19.7 10.0 (% fruit) Unacceptable 9.0 6.9 15.0 3.0 3.0 13.5 6.4 20.5 (% fruit)

2.3 Length of time in the supply chain

Time in the supply chain during the 2010/11 season The time that the fruit spent in the supply chain from packing to retail varied with the time of the season. Figure 30 shows that early in the 2010/11 season, fruit on retail display had normally been packed within the last five days. This remained the case during the season until the picking season was coming to an end. From the 25 January 2011, the storage times began to increase with average time between picking and packing extending to 15 days by mid February 2011. The longest time recorded in this survey between the time of packing and retail sale was 21 days (at the end of the survey period).

10 Days afterpackingDays

0 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011

Sampling date

Figure 30. Length time between when fruit was packed and when placed on retail display in South Australian stores in the 2010/11 season.

Time in the supply chain in 2011/12 season The time that the fruit spent in the supply chain from packing to retail in the 2011/12 season similarly varied with the time of the season. Figure 31 shows that early in the season fruit on retail display in the 2011/12 season had normally been packed within the last two to ten days. This remained the case for the majority of cherries supplied throughout the season with only occasional supplies over ten days old. This data suggests most retailers had a turnover of their cherries that allowed for minimum storage with the maximum time between packing and retail display recorded in this survey being 15 days.

Figure 31. Length time between when fruit was packed and when placed on retail display in SA and NSW stores.

Impact on quality of delay to retail sale Under optimum conditions sound quality cherries can be stored in excellent condition for longer than the maximum time between packing and retail display recorded in this survey (21 days). Ideally storage of fruit should be minimised, as storage conditions in the supply chain are not always optimal and fruit quality at the beginning of the storage period is not always sound. More often than not, fruit will deteriorate in storage for these reasons, highlighted by the storage testing reported in the later section. In this survey in the 2010/11 and 2011/12 season, any storage of fruit in the supply chain was a result of commercial practices. As the trial was not specifically set up to assess the deterioration of fruit from delays by comparing like fruit with like fruit, any impacts or lack of impacts found should be viewed with caution. Additionally, the majority of fruit storage in the supply chain occurred towards the end of the harvesting season, being used to extend the marketing season for cherries. This has the potential to skew the findings from the survey. Fruit stored for longer periods tended to have lower stem pull forces and titratable acidity levels which could be expected as both parameters are known to reduce in storage. Similarly an increase in ‘darkness’ of the fruit colour occurs during storage. The firmness, flavour and total soluble solids levels of fruit did not seem to be substantially impacted by fruit spending longer in the supply chain.

2.4 Quality change in the retail environment

Background Fruit were sampled twice a week from three stores in South Australia in the 2010/11 season. When available, samples of fruit were obtained from the retail display and from unopened boxes that were being held in the stores cool room. Stores prefer to minimise stock inventory in the cool room, as they have daily orders and can order fresh stock each day. Therefore stores did not always have stock on hand in the cool room. On sampling occasions where this was the case, the data collected on the retail sample were omitted from this comparison. This was done to balance the data and minimise skewing due to seasonal trends that were substantial. It is important to note that due to new orders / deliveries each day, the samples on retail display were not always of the same variety or from the same source as the sample held in the cool room. In addition the duration that the fruit had spent on the retail display prior to sampling varied, as did the timing and level of removal of poor quality fruit by store staff in the period leading up to sampling.

Results and general discussion The results and observations show that some of the deterioration in product quality does occur while fruit is on retail display. The most obvious and consistent difference between samples observed out of the cool room and from the retail display was in stem quality, specifically stem browning. Stems of fruit sampled from retail display were more browned than that of fruit sampled from the cool room. In addition, the level of fruit bruising was an issue, particularly in the later part of the season. However less obvious differences occurred in the firmness, colour and size of fruit. Differences in other parameters measured between the cool room and retail display samples in this survey were generally inconsistent or small (flavour, total soluble solids, titratable acidity and stem pull force, data not shown). Observations in this survey indicate that factors prior to being placed on retail display are more important for these quality parameters than changes that are occurring once fruit is placed on display. However the significant deterioration in stem colour can be addressed.

Stem colour Stem quality of fruit sampled from the retail display was of lower quality (browner) than that of the fruit sampled from the cool room of stores averaged over the 10 week survey period (Figure 32). These observations suggest that significant losses in stem quality occur while the fruit is on retail display. Of samples taken from the cool rooms of the stores, 79% of samples had stems averaging less than 10% browning. Stems with less than 10% browning can be regarded as visually fresh and green. This compares with less than 30% of the samples taken off the retail display that had stems appearing fresh and green. The majority of samples of fruit on retail display had stems that were noticeably brown and did not appear fresh and green.

Cool room > 25% Retail Cool room Retail 10-25%

Stembrowning <10%

Green 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011

Sampling date

Figure 32. Level of stem browning of fruit sampled from retail display compared with fruit sampled from cool rooms of stores in South Australia during a ten week period in the 2010/11 season.

The level of stem browning observed on fruit prior to being placed on retail display at each of the three stores was similar, when averaged over the 10 week sampling period (Figure 33). However the retention of stem quality as reflected by fruit sampled off retail displays was better at store A than stores B and C. This suggests that the practices at Store A were more favourable for the retention of stem quality. Cherries from stores B and C were almost exclusively sampled from open refrigerated displays while samples at store A were sampled from refrigerated displays approximately 40% of the time and from ambient displays approximately 60% of the time. Cherries having both good and bad quality stems were found from both refrigerated and non refrigerated retail displays (Figure 34). These results were not obtained under controlled trial conditions and therefore were not comparing like fruit with like fruit and as such should not be relied upon. However these observations suggest that utilising open refrigerated displays is not necessarily the answer to improving the retention of green stems at the retail level (Figure 34). Display at ambient conditions can also have negative impacts on fruit quality (such as firmness and rot development) when compared with display under refrigerated conditions and this is discussed in later sections.

> 25% Cool room Retail

10-25% Stembrowning <10%

Green Adelaide Store A Adelaide Store B Adelaide Store C

Sampling location

Figure 33. Average level of stem browning of cherries sourced from retail display or out of the cool room at three stores in Adelaide over a ten week period in the 2010/11 season.

> 25%

Refrigerated display Ambient display 10-25% Stembrowning <10%

Green 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011

Sampling date

Figure 34. Stem quality of cherries sourced from either an open refrigerated or ambient retail display at store A in Adelaide over a ten week period in the 2010/11 season.

In addition to the browning of stems, the attachment of the stem to the fruit is an important attribute to fruit quality and in this survey there were also significant levels of stem losses observed. The percentage of stem loss was slightly higher on fruit sampled at retail level than on fruit sampled from the cool rooms of stores,

53 particularly at Store A (Figure 35). On average, the fruit sampled from the cool room of Store A had less attached stems than that of Stores B and C. More importantly the majority of stem loss appeared to have occurred before fruit was placed on display, suggesting retail practices were not the primary cause of stem loss on the fruit surveyed.

20 Cool room Retail 15

Stemless fruit Stemless (%) 5

0 Adelaide Store A Adelaide Store B Adelaide Store C

Sampling location

Figure 35. Average percentage of fruit with no stems of cherries sourced from retail display or out of the cool room at three stores in Adelaide over a ten week period in the 2010/11 season.

Implications for industry The benefits from the high levels of investment at the production and packing shed stages of the supply chain to rapidly pre-cool and subsequently manage temperature, thus maintaining stem colour, can be quickly undone at the retail level. Current practices do not appear to be adequately maintaining stem colour in retail displays. The loss of stem quality on the retail shelf at this final stage before purchase would impact on the perceived freshness of the cherries as viewed by shoppers. Key factors that influence Loss of stem quality is often the first sign of deterioration seen when cherries are exposed to higher than optimal temperatures and / or low humidity conditions (McGlasson et al., 2007). Water loss contributes significantly to the loss of stem quality that is visually seen. The desire of retailers to present cherries in an open display can result in the exposure of fruit to warm dry air. Presentation of the fruit in refrigerated displays would seem an obvious solution to this problem. However the use of these displays did not seem to result in better stem quality in this survey. A number of factors may have contributed to this finding. Sales from the less prominently positioned refrigerated displays may have been lower resulting in longer duration between stock rotations than from the ambient displays. Refrigeration

54 systems operating in open environments can also dry out the air, thus being as damaging to stem quality as holding fruit at ambient conditions. However no measurements of refrigerated or non-refrigerated retail environment were taken. Suggested strategies to improve performance Based on the observations made in this survey a more in depth investigation of the techniques used to preserve the quality of cherries, particularly stem quality should be undertaken in conjunction with the retailer. The merits of the use of refrigerated displays for cherries should be investigated in terms of the impact on sales volumes and consumer perception, benefits to fruit and stem quality and overall return of the category at a range of price points. Holding fruit in refrigerated displays impacts on a range of fruit quality parameters. However this review must also include investigating other important fruit quality parameters such as softening and rot development.

Fruit firmness Firmness of the fruit (as measured with the FirmTech instrument sampled from the retail display) was generally softer than that of the fruit sampled from the cool room of stores on the same day (Figure 36). This lower firmness of fruit on retail display was observed at each of the three stores, with the average difference the highest at store B (38 g/mm) and the lowest at store A (21 g/mm) (Figure 37). Note fruit samples collected from retail display at store C were always refrigerated, which was also the case for 90% of samples collected from store B. Note that all FirmTech measurements are conducted on fruit at room temperatures (20oC), so no physical temperature effects on fruit texture occurred.

600 Cool room Retail 500 Cool room Retail 400

300

200 Fruit firmness (g/mm)Fruit firmness

100

0 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011

Sampling date

Figure 36. Firmness of fruit sampled from retail display compared with fruit sampled from cool rooms of stores in South Australia during a ten week period in the 2010/11 season.

350 Cool room 300 Retail

250

200

150

100 Fruit firmness (g/mm) Fruit firmness

0 Adelaide Store A Adelaide Store B Adelaide Store C

Sampling location

Figure 37. Average firmness of fruit sourced from retail display or out of the cool room at three stores in Adelaide over a ten week period in the 2010/11 season.

Implications for industry Firmness is a key quality criterion in the eating quality of cherries. In an open display, soft cherries are very noticeable when shoppers are selecting fruit to purchase. Presence of soft cherries in retail displays can result in the loss of sales, or the excessive picking over of fruit when purchasing. When shoppers pick over fruit this tends to detract further from the remaining fruit on sale, by both concentrating the number of poor quality cherries and causing further physical damage (such as stem removal and additional fruit bruising). Key factors that influence Some cherries rapidly lose firmness when taken out of cool storage and are held at room temperatures. Apart from the temperature at which they are handled, firmness retention is dependent on the inherent characteristics of the cherry (Rettke, 2011). Selecting the right varieties and growing them using production practices that enhance their firmness and its retention as the fruit moves through the supply chain are key prerequisites for delivering fruit with the desired firmness and eating texture to consumers. Soft cherries are also prone to bruising during harvest and postharvest handling, which further exacerbates softening. Suggested strategies to improve performance Temperature management is an important means of retaining the firmness of fruit. Use of refrigerated displays at the retail level will help reduce the loss of firmness. Rapid stock rotation will reduce the loss in firmness. Even where fruit is displayed at

56 ambient temperature, its quick sale within hours of display will not allow time for the cherries to soften. Strategies at the retail level that minimise the handling of fruit will assist in reducing bruising of fruit. Where fruit is sold loose, the regular removal of poor quality fruit will reduce the desire of shoppers to pick over fruit, damaging it further. Unit packaging that prevents the shopper from handling individual fruit eliminates this problem. However none of these strategies will improve fruit that was inherently soft or had poor eating texture to start with. Therefore the presentation of good quality fruit to the consumer relies on producing good quality fruit from the orchard.

Bruising The average incidence of bruised fruit on the fruit sampled from the retail display was more than double that on fruit sampled from the cool room of stores over the 10 week survey period (Figure 38). This higher incidence of bruised fruit on retail display was observed at each of the three stores over the season (Figure 39).

30 Cool room Retail 25 Cool room

20 Retail

Incidencemajorbruisingof (%) 5

0 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011

Sampling date

Figure 38. Incidence of bruised fruit sampled from retail display compared with fruit sampled from cool rooms of stores in South Australia during a ten week period in the 2010/11 season.

10 Cool room Retail 8

2 Incidencemajor ofbruising (%)

0 Adelaide Store A Adelaide Store B Adelaide Store C

Sampling location

Figure 39. Incidence of fruit showing major bruising sourced from retail display or out of the cool room at three stores in Adelaide over a ten week period in the 2010/11 season.

Implications for industry The high level of bruised fruit on the retail market is a significant issue for industry. Bruised fruit is less visually attractive than sound fruit and are more susceptible to the development of postharvest rots. However the impact on fruit texture is just or more damaging to consumer perceptions. When a shopper picks up a bruised fruit, its soft and mushy feel is immediately obvious and a purchase may be lost. If purchased, the fruit will either be later discarded or if eaten, will generally leave the consumer with an off flavour in their mouth to go with the initial disappointment of its lack of crunch. Most consumers will not notice the flesh of the fruit has an off-putting brown colour when eaten, therefore minimising the incidence of soft bruised fruit is a key market imperative. Key factors that influence Lack of firmness of the fruit is a key driver of increased bruising incidence. Sound firm cherries that are handled appropriately will not exhibit bruising in the market place. Practices that compromise the firmness of the fruit will lead to a higher incidence of bruising, which will then be exacerbated as shoppers pick over the fruit at retail level. However, good postharvest handling of the fruit from the orchard to the consumer is essential. Even though the fruit may appear sound and free of bruises at the time of packing, the flesh discolouration and softening associated with bruise development can occur during storage, transport and display.

Suggested strategies to improve performance Postharvest handling and packing practices need to be continually monitored to ensure common practices such as size grading and packing are not contributing to the bruising problem. It is suggested that monitoring and follow up assessment of fruit bruising is integrated in QA practises. Practices that reduce the loss of firmness before sale, such as good temperature management and rapid stock rotation, are the most effective means of minimising bruising at retail level. Strategies at the retail level that minimise the handling of fruit will assist in reducing bruising of fruit. Where fruit is sold loose the regular removal of poor quality fruit will reduce the desire of shoppers to pick over fruit, damaging it further. Unit packaging that prevents the shopper from handling individual fruit eliminates this problem. However it is important to note that none of these packing and retail strategies will improve fruit that was bruised or inherently soft to start with.

Fruit colour Observations over the ten week survey period suggest that fruit sampled from the retail display was slightly darker than fruit sampled from the stores’ cool room (Figure 40). However this small average difference (approximately 1/10 of a colour grade) is inconsequential compared with differences that exist between fruit within a box, let alone between different samples. As such the level of fruit darkening that may occur at the retail level does not warrant commercial consideration.

Cool room 7 Retail

6 Cool room Retail

5 Fruitcolour 4

1 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011 Sampling date

Figure 40. Colour of fruit sampled from retail display compared with fruit sampled from cool rooms of stores in South Australia during a ten week period in the 2010/11 season.

Fruit size The average size of fruit over the 10 week survey period sampled from the retail displays was slightly smaller (<1mm) in diameter than fruit sampled from the stores cool store. This is most likely associated with weight loss on retail display, though specific weight loss measurements were not made on fruit as it moved through the system (Figure 41).

30 Cool room Retail 25 Coolroom

20 Retail

15 Fruit size (mm) Fruitsize 10

0 8/12/2010 28/12/2010 17/01/2011 6/02/2011 26/02/2011

Sampling date

Figure 41. Size of fruit sampled from retail display compared with fruit sampled from cool rooms of stores in South Australia during a ten week period in the 2010/11 season.

2.5 Changes in fruit quality stored after purchase

Background Consumers generally purchase cherry fruit from the market to be eaten at a later time, sometimes up to a week after purchase. To investigate the shelf-life / consumer life of the fruit after a short storage period, a sample of fruit from the retail store in the 2010/11 season was stored for an additional one week at 5oC. This storage time and temperature combination was chosen as the maximum storage period for the consumer. Fruit was sampled from different stores in NSW every week during the season and stored at Gosford Primary Industries Institute. Fruit was purchased from the retail market and assessed for initial fruit quality. The fruit was then stored in the standard polyethylene plastic bag at 5oC for one week before final quality assessment.

Overall fruit quality The average level of unacceptable fruit (as determined by defects and rots, rather than consumer taste testing) in samples utilised for this study was 4%. This was assessed from a 50 fruit subsample of fruit purchased from each store. Only fruit sampled from the back cool room were stored. After the storage period of one week at 5oC, the average level of unacceptable fruit increased to 12%. The percentage of unacceptable fruit during each week across the season both at purchase and after one week storage at 5oC is presented in Figure 42. The results show that on average there was a three fold increase in unacceptable fruit during cold storage, and in the worst case after one week cold storage more than 60% of the fruit were unacceptable.

70 After storage 60 At purchase

20 %Unacceptable fruit 10

1 2 3 4 5 6 7 8 9 10 12 13 14 Sampling time

Figure 42. Percentage of unacceptable fruit during each week across the 2010/11 season in NSW, both at purchase and after one week storage at 5oC.

The ranking of major defects that were responsible for the high levels of unacceptable fruit quality clearly shows that rots were the major storage issue, accounting for 42% of all defects. Pitting and bruising were also significant major and minor defects across the entire season at purchase and after storage (Table 7). These three defects (major and minor) accounted for over 87% of all defects across the season and during storage. Table 7. The ranking and percentage contribution of the different major and minor defects in cherry fruit quality across the 2010/11 season after one week storage at 5oC.

Major Defects % Minor Defects %

1 Major Rot 33.0 1 Minor Pitting 17.2

2 Major Pitting 8.4 2 Minor Rot 11.7

3 Major Bruising 5.9 3 Minor Bruising 10.5

4 Major Nose Crack 1.8 4 Minor Dry Split 2.5

5 Major Wet Split 1.0 5 Minor Nose Crack 2.1

6 Major Scarring 0.7 6 Minor Scarring 1.8

7 Major Suture Split 0.5 7 Insect Damage 1.0

8 Major Stem Crack 0.1 8 Growth Deformity 0.5

9 Major Thrip 0.0 9 Minor Stem Crack 0.4

10 Minor Thrip 0.3

11 Bird Damage 0.2

12 Growth Deformity 0.1

13 Immature 0.1

14 Double 0.1

15 Spur 0.0

Implications for industry As expected the addition of a short storage after purchase of the cherry fruit resulted in the increase in the level of unacceptable fruit. Average increase in unacceptable fruit was three fold during the one week storage period. This indicates that consumers who had stored their cherries at home in the refrigerator risked throwing a high proportion of their purchase out due to the progression of postharvest rots. The lack of postharvest storage life (particularly from rots) of some lines on fruit is a concern for industry and should be investigated.

Key factors that influence Rots are key determinant of postharvest storage life. Cherries are susceptible to decay caused by several pathogens, including Penicillium expansum, Botrytis cinerea, Monilinia spp., Alternaria spp. and Rhizopus stolonifer. Fruits injured during harvest and handling may come into contact with pathogens when they are packed, stored or shipped. Many of these pathogens are wound parasites and in most cases require a wound in the skin or stem to come into contact with susceptible tissue and initiate infection. Adequate in-field control of cherry pathogens is critical. An orchard protection regime against diseases will reduce the pathogens in the harvested fruit. Suggested strategies to improve performance Good postharvest techniques such as careful handling, good postharvest temperature control can minimise the development of postharvest rots. However the control of storage rots begins in the orchard where good orchard management such as targeted sprays and orchard hygiene can help minimise the disease pressures. In addition it is important that the appropriate use of postharvest sanitisers and fungicides where appropriate is maintained.

Fruit colour The colour of the fruit generally increased during cold storage at 5oC for one week (Figure 43). The average increase in Colour Grade was 0.2 of a scoring unit; however the increases in fruit colour were greater in the early part of the season, where fruit colour at purchase was ‘lighter’ red. At the end of the season, where most of the fruit had already been stored, the fruit colour was substantially darker upon purchase with little increase in fruit colour was observed during storage. However it is expected that the observed slight increase in fruit colour during storage is not likely to affect consumer attitudes to the fruit.

6 After storage At purchase 5

3 Fruitcolour

1 2 3 4 5 6 7 8 9 3 4 10 12 1 1 Sampling time

Figure 43. Average fruit colour score of cherry fruit across the 2010/11 season of NSW fruit, both at purchase and after one week storage at 5oC. Each point is the average fruit colour score of 25 fruit. Fruit colour was scored (1-6) using the ‘Australian Cherry Colour Chart’.

Fruit firmness The average firmness of fruit samples across the season both at purchase and after one week storage at 5oC is presented in Figure 44. Although the average firmness decrease was only 4 g/mm, different lines of fruit became either softer or firmer during cold storage. The negative firmness numbers indicate that the firmness was less after storage than the initial firmness measurement at purchase (blue), ie the fruit became softer during storage. However a significant number of fruit lines also became firmer during storage. The range of firmness differences between purchase and after storage ranged from - 47 g force /mm (ie softer) to + 45 g force /mm (ie firmer). As all fruit were stored under the same conditions (ie same temperature, relative humidity) and storage time, there are some interesting observations on why some fruit soften and some fruit become firmer during storage that requires further work.

500 After storage At purchase 400

300

200

100 FirmtechFirmness

1 2 3 4 5 6 7 8 9 10 12 13 14 -100 Sampling time

Figure 44. Average cherry fruit firmness (g force /mm) of fruit samples across the 2010/11 season both at purchase and after one week storage at 5oC. Each point is the average fruit firmness of 25 fruit as measured with the FirmTech instrument. The negative results show that the firmness was less after storage than the initial firmness measurement at purchase, ie the fruit became softer during storage.

Implications for industry In general, the decline in fruit firmness during storage was lower than the variability between the lines, suggesting that variability in firmness at the time of purchase was of greater concern than changes in storage after purchase. Where firmness of the fruit was marginal at the time of purchase, further decrease in firmness would impact on consumer appeal. In addition, other quality parameters, especially when

64 significant storage disorders (pitting) and postharvest rots were present, are more important considerations when consumers store fruit after purchase. Key factors that influence Fruit firmness is affected by storage conditions. Storage at low temperatures under high humidity is a key storage criterion to maintain fruit firmness. More research into the post-storage retail outcomes of different lines of fruit may reveal different preharvest factors that affect postharvest storage life. Suggested strategies to improve performance It is important to reinforce the importance of prompt pre-cooling after harvest and subsequent best practice temperature management as a means of retaining the firmness of fruit. Maintaining the cool chain to the consumer will maintain fruit firmness and decrease the development of postharvest rots. It is important to note that postharvest practices cannot be relied upon to improve fruit that was inherently soft to start with.

Stem colour As expected the level of stem browning increased during storage (Figure 45). The average level of stem browning increased 0.4 of a score grade, where the average stem condition was a Colour Grade score of 3 (ie. 10 - 25% of the stem was brown). Some lines of fruit had no / very little increase in stem browning, whilst other lines had high levels of browning occurring during storage. As all fruit were stored under the same storage conditions (5oC in plastic over-wrap bags), this observation needs to be followed up as there maybe some pre-harvest, or varietal effect which retains good stem condition during storage. There were no clear correlations between variety, growing region, time of year etc and browning of stems in storage in this survey. This is not unexpected in this type of survey data due to the high number of variables that impact on any given quality trait of an individual sample. Therefore more work is required to investigate these differences.

65 brown 4 After storage At Purchase

2 Stembrowning

green 1

1 2 3 4 5 6 7 8 9 0 2 4 1 1 13 1 Sampling time

Figure 45. Average stem browning score of cherry fruit across the 2010/11 season both at purchase and after one week storage at 5oC. Each point is the average stem browning score of 50 fruit. (Stem scale score 1 is bright green stem condition, score 2 is <10% stem browning, score 3 is between 10 – 25% stem browning and score 4 is >25% stem browning).

Stem pull force The results of the average stem pull force (g) of fruit samples across the season both at purchase and after one week storage at 5oC is presented in Figure 46. The average force to remove the stem from the fruit across the season was - 41g force lower after storage, than at purchase. This means that on average, the stem detached from the fruit easier after storage, than at purchase. However there were some exceptions, where fruit retained their stems the same, or more strongly after storage. There appeared to be no correlations between varieties, growing region, time of year etc which related to the change in stem pull force. Therefore more work is required to investigate these differences.

800 After storage At purchase 600

400

200

Stempull force 0

1 2 3 4 5 6 7 8 9 10 12 13 14 -200

-400 Sampling time

Figure 46. Average stem pull force (g) of fruit samples across the 2010/11 season both at purchase and after one week storage at 5oC. Each point is the average stem pull force of 25 fruit. The negative results show that the stem pull force was less after storage than at purchase, ie the stems pulled from the fruit more readily after storage.

Implications for industry The presentation of the stem condition to the final consumer is paramount to the successful marketing of cherries. Transport and storage are necessary elements of the supply chain, and these must be managed to maintain fruit quality. But as previously shown, much of the deterioration in stem quality was already evident at time of purchase from the retail display. Given that the increase in stem browning during storage is not unexpected, the loss of stem quality during the consumer shelf test is not as damaging as the loss on retail display. Key factors that influence Stem quality deteriorates with any storage time, but its rate of deterioration can be managed by maintaining high humidity and appropriate temperature control. Different cherry varieties have different susceptibilities to stem deterioration. Cherry varieties with thick green stems such as Rons store well, whilst other varieties with more ‘sensitive’ stems are more prone to stem browning / deterioration. Suggested strategies to improve performance Good harvest and postharvest treatments such as rapid pre-cooling and refrigeration are known to reduce stem deterioration, but the results of the previous section illustrate that more work is required to quantify this. It is also important to educate

67 consumers on the best methods to store their fruit when they get it home, i.e. leave the cherry fruit in the plastic shopping bag and keep in the refrigerator.

Fruit total soluble solids The fruit TSS level at purchase and after storage across the season is presented in Figure 47. The negative results in the figure show that the levels of TSS were less after storage than the initial TSS level at purchase (blue). Different lines of fruit responded differently to cold storage. Some fruit appeared to develop higher TSS levels during storage, whilst other lines appeared to have lower TSS levels during storage. It is important to note there is sampling variation in these observations and more detailed work is required to quantify and test these individual observations. However, overall average across all lines across the season, there was no change in the TSS level between fruit at purchase and after one week cold storage.

20 After storage At purchase 15

SSC(%) 5

1 2 3 4 5 6 7 8 9 0 2 1 1 13 14 -5 Sampling time

Figure 47. Average cherry fruit total soluble solids content (TSS) of fruit samples across the 2010/11 season both at purchase and after one week storage at 5oC. The negative results show that the levels of TSS were less after storage than the initial TSS level at purchase. Each point is average from the juice of 10 fruit.

Fruit acidity The average levels of titratable acid (TA) (g equivalent malic acid / 100 ml) of cherries across the season both at purchase and after one week storage at 5oC is presented in Figure 48. As expected, the results show that fruit TA levels consistently decreased during the cold storage period.

1 After storage 0.8 At purchase

0.6

0.4

Acidity 0.2

1 2 3 4 5 6 7 8 9 2 10 1 13 14 -0.2

-0.4 Sampling time

Figure 48. Average titratable acidity (TA) level (g equivalent malic acid / 100 ml) of fruit samples across the 2010/11 season both at purchase and after one week storage at 5oC. The negative results show that the decline in the levels of TA during storage from the initial TSS level at purchase. Each point is average from the juice of 10 fruit.

Implications for industry The maintenance of TSS and the reduction of TA in stored fruit would result in fruit with lower TSS/TA ratio. This may promote fruit with a more bland taste with less flavour. However the impact of the loss of TA in storage on flavour is dependent on the TSS and TA levels at harvest. Key factors that influence To satisfy the consumer, fruit needs to have sufficient TSS and a good balance of TA at harvest. It is generally considered that the fruit TSS does not dramatically change after harvest, and can be managed using best practice postharvest practices. However TA levels are known to decrease during storage. Suggested strategies to improve performance Maintaining the cold chain significantly reduces the losses of TSS and TA during storage. In addition the use of modified atmospheres can assist in minimising the loss of TA in storage.

Subjective sensory quality assessment Cherry fruit were subjectively tasted and assessed for overall quality. The average subjective flavour score of cherries in each of the retail stores during each week of the season is presented in Figure 49, where a score of 1 was judged as ‘Excellent’ and a score of 4 was ‘Unacceptable’. However there appeared to be a decline in eating quality during storage time of the early season fruit (weeks 2-4). This was probably due to the decline in both TSS and acidity during storage of the early fruit (Figure 47 and 48), but more detailed experimental work is required to confirm this.

4 After storage 3 At purchase

0 Flavourscore

1 2 3 4 5 6 7 8 9 0 2 3 4 1 1 1 1 -1

-2 Sampling time

Figure 49. The subjective average overall consumer acceptability score of fruit samples across the 2010/11 season both at purchase and after one week storage at 5oC. Cherry acceptability was subjectively rated using a 4 point rating scale (1 = excellent, 2 = good, 3 = acceptable and 4 = unacceptable). The negative results show that the decline in acceptability of the fruit from the initial sensory acceptability levels at purchase.

Implications for industry Fruit flavour was marginal in the 2010/11 season due to the difficult growing conditions. Flavour of fruit generally deteriorates in storage. Only high quality fruit with good eating quality should be stored. Consumers who store poor quality fruit will be even more disappointed when it is eaten. The loss of fruit TA during storage affects the eating quality of cherries. However we do not know what TSS/TA ratio is preferred by consumers at different TSS levels and for different varieties. Key factors that influence The perception of good flavour is generally thought to be influenced by the balance of TSS and TA. The levels of these fruit quality parameters are initially determined at harvest by variety and growing conditions. Fruit with high TSS will generally satisfy

70 the consumer, but fruit with marginal TSS levels can taste poor, if the TA levels are low. During storage, the levels of TA in cherry fruit can significantly decline and affect flavour perception. Therefore the decline of TA during storage needs to be managed. For example, good postharvest practices (such as cool chain, MA bags etc) help maintain the eating quality of cherry fruit. Suggested strategies to improve performance The maintenance of taste and flavour is critical in satisfying consumers and ensuring repeat purchases. Good postharvest practices and the cool chain underlie the supply of good tasting fruit to the consumer. Improving fruit quality will rely on what the consumer requires. Little research has been conducted on consumer preferences with TSS/TA and other fruit quality attributes. More research is required to identify what TSS, TA and the ratio of TSS/TA are preferred by consumers on a varietal basis, then pre- and postharvest management strategies can be developed to deliver these attributes.

3. Preliminary identification of the causes of cherry fruit quality defects Background Cherry fruit are very susceptible to mechanical damage that occurs during picking, packing and transport of cherries to market. After several days in storage, damaged fruit develop small sunken areas on the fruit surface (pits), or larger flattened areas, (bruises). Pitting is thought to result from impacts with fruit stems or with hard surfaces, in which impact forces are concentrated in a small area of the fruit surface. Bruising, on the other hand, results when impact forces are spread over a large area (Thompson et al., 1995). The expression of the symptoms occurs after cold storage when the collapse of the cells occurs; therefore it is difficult to sort during the packing line operations. This makes this postharvest issue a significant problem for industry. In addition to obvious postharvest factors (such as impact damage) that affect pitting damage, several preharvest factors have been identified that affect the susceptibility to mechanical damage. For example, low soluble solids concentration, low fruit temperatures and small fruit size have been associated with greater susceptibility to mechanical damage in cherry, while preharvest gibberellic acid sprays and postharvest calcium dips have been shown to reduce damage susceptibility (Grant and Thompson, 1997). Zoffoli et al. (2008) also reported that a fruit thinning treatment of 3 to 4 fruits/spur produced the largest fruit with high soluble solids concentration and was the most resistant to impact bruising. The postharvest evaluation showed that fruit thinning treatments yielded the lowest percentage of pitting after storage. Pitting damage is also influenced by variety (Porritt et al., 1971) and while pitting susceptibility is influenced by maturity in Van (Lidster et al., 1980) and Lambert cherries (Couey and Wright, 1974), there have been few investigations on this relationship in newer varieties used by industry. Although Toivonen et al. (2004) showed that Bing, Lapins, and Sweetheart cherries showed a decline in susceptibility as the fruit matured and that Bing showed the greatest susceptibility to pitting. Hence there is a preharvest effect that interacts with postharvest handling to affect pitting. Pitting and bruising are significant commercial problems for the Australian cherry industry. These defects not only detract from the appearance and saleability of fruit in the marketplace but also hasten fruit deterioration. Indeed the results of the retail survey from 2010/11 season showed there was high level of unacceptable fruit was primarily due to pitting, bruising and rots. These three reasons accounted for over ⅔ of all the major defects observed across the season. Similarly, pitting and bruising were also responsible for ⅔ of the level of minor defects. These levels of defects are well above the acceptable limits of defects and were investigated in this preliminary survey of seven commercial packingsheds in the 2011/12 season. Aim Identify the causes of pitting, bruising, rots and stem damage that are responsible for downgrading fruit quality. This survey occurred from orchard to the packed box before delivery to market at seven different cherry packingsheds in the Adelaide Hills, Young and Orange districts during the 2011/12 cherry season.

Methods Seven different commercial orchard / packing line combinations were assessed in the Adelaide Hills (SA), Young (NSW) and Orange (NSW) during the 2011/12 season. The cherry sheds and the varieties assessed during the 2011/12 season were:

Packingshed Location Variety assessed Shed 1 Young, NSW Lapin Shed 2 Young, NSW Lapin Shed 3 Young, NSW Simones Shed 4 Young, NSW Vans Shed 5 Orange, NSW Sweet Georgia Shed 6 Adelaide Hills, SA Lapin Shed 7 Adelaide Hills, SA Stella

At each orchard / packingshed, samples of fruit were removed, stored then checked for the development of defects. Samples were removed at key points in the handling of cherries from orchard to the packed fruit. The ideal fruit sampling points include: Sampling point 1 Directly from the tree Sampling point 2 After harvest / out of field bin Sampling point 3 At arrival at packinghouse Sampling point 4 Before loading on packing line Sampling point 5 Out of the water dump Sampling point 6 Off feed conveyor Sampling point 7 After hand sort / grade Sampling point 8 After the cluster cutters Sampling point 9 Out of water transfer Sampling point 10 After belt / sizing grader (rollers) Sampling point 11 From closed box on the pallet

However as each harvesting / packing operation is unique; it was not possible to obtain samples at each of these sampling points. For example, in most instances,

73 cherries were harvested the previous day, hydrocooled and stored overnight before packing. Therefore it was not possible to always collect fruit from the orchard for this survey. This was a limited survey to identify the postharvest causes of pitting, bruising and rots in different representative packingsheds. Sampling procedure At each of the sampling points four different lots (replicates) of 25 fruit were removed from the line. The sampled fruit were carefully placed in cushioned single layers and placed into 500g plastic punnets (Figure 50). This handling procedure ensured that there was no fruit damage during transport, handling or storage.

Figure 50. Packing of sample fruit from different parts of the cherry packing line (left). Storage of samples at 0oC before assessment for fruit quality and defects (right).

Storage of fruit Fruit were stored in plastic over-wrapped trays at 0oC for four weeks with a one day shelf life treatment at 20oC before subjective assessment of fruit quality and defects.

Assessment of fruit quality and defects Pitting. Pitting was assessed as either not present, minor (2-5mm in diameter) and major (>5mm in diameter). Bruising. Bruising was assessed as either not present, minor (still acceptable) and major (not acceptable). Rots. Any rots are unacceptable. The subjective scoring system was either no rots, minor / slight rots or major rots. Stem browning. Stem retention and stem browning was assessed as a subjective score as previously described.

In addition, fruit quality (fruit colour, firmness (FirmTech, BioWorks, USA), subjective flavour, TSS and TA) were measured after four weeks storage.

Results The results of the different packingsheds will be reported individually then discussed as a whole in the general conclusions.

Shed 1 Cherry packingshed 1 was in Young, NSW. Lapin cherry fruit (average skin colour score 5.1 (Australian Cherry Guide) and average 13.8% TSS) were sampled throughout the packing line on 6 December 2011. The different sampling points are described in Table 8.

Table 8. The sampling points of Lapin cherry fruit from Shed 1 Sampling point 1 From bin from the cool room Sampling point 2 Before the cluster cutter Sampling point 3 After the cluster cutter Sampling point 4 After the sizer Sampling point 5 After the sizing run Sampling point 6 From the flume onto the conveyor Sampling point 7 From the hand sorting conveyor Sampling point 8 From the packed box (28mm)

Overall, this packing line resulted in a good quality cherry pack. The results showed that significant pitting occurred in the last part of the packing process (ie from the hand sorting and packing into the box). The level of major pitting from the packed box of fruit after four weeks storage at 0oC was 20% of all fruit (Figure 51 and Figure 52). The level of major / unacceptable bruising was 20% of all fruit across all the sampling points in the line (Figure 53). The number of rots was highest after the sizer and sizing run (sampling point 4 and 5) (Figure 54). Packing did not seem to affect the level of stem retention, stem condition / browning (Figure 55), nor the flesh firmness (Figure 56), as all cherries from the different sampling points had similar levels after cold storage.

Shed 1 - Minor Pitting % Shed 1 - Major Pitting % 100 100 90 90 80 80 70 70 60 60

(%) 50 (%) 50 40 40 30 30 20 20 10 10 Percentage pittedof cherries Percentage pittedof cherries 0 0 initial1 2 3 4 5 6 7 8 initial1 2 3 4 5 6 7 8 Sampling Point Sampling Point Figure 51. The percentage of fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 1 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 8.

Shed 1 - Minor Pitting Shed 1 - Major Pitting 2 2 1.8 1.8 1.6 1.6 1.4 1.4 1.2 1.2 1 1 0.8 0.8

sample (/75) 0.6 sample (/75) 0.6 0.4 0.4 0.2 0.2 Average number pitsperof 0 Average number pitsperof 0 initial1 2 3 4 5 6 7 8 initial1 2 3 4 5 6 7 8 Sampling Point Sampling Point Figure 52. The average number of pits per cherry fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 1 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 8.

Shed 1 - Minor Bruising % Shed 1 - Major Bruising % 100 100 90 90 80 80 70 70 60 60 50 50 40 40

cherries (%) 30 cherries (%) 30 20 20 Percentagebruisedof Percentagebruisedof 10 10 0 0 initial1 2 3 4 5 6 7 8 initial1 2 3 4 5 6 7 8 Sampling Point Sampling Point Figure 53. The percentage of fruit with minor bruising (acceptable) and major bruising (unacceptable bruising) in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 1 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 8.

Shed 1 - Rots % 100 90 80 70 60 50 40 cherries (%) 30

Percentage of rotten 20 10 0 initial1 2 3 4 5 6 7 8 Sampling Point Figure 54. The percentage of fruit with rots in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 1 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 8.

Shed 1 - Stems intact % Shed 1 - Stem Scores 100 4 90 80 70 3 60 50 stems(%) 40 30 2 Percentage intact of 20 >25% is brown

10 = 100% green, 2 <10% brown, 310-25% is brown,4 0 Averave StemScore where1 1 initial1 2 3 4 5 6 7 8 initial1 2 3 4 5 6 7 8 Sampling Point Sampling Point Figure 55. The percentage of fruit with intact stems (left) and the average stems scores (right) in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 1 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 8.

Shed 1 - Firmness 500 450 400 350 300 250 200 150 Firmness(g) 100 50 0 initial1 2 3 4 5 6 7 8 Sampling Point Figure 56. The average firmness (g/m2) as measured with the FirmTech in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 1 and stored for four weeks at 0oC. (n = 25 fruit). The different sampling points in the line are described in Table 8.

Shed 2 Cherry packingshed 2 was in Young, NSW. Lapin cherry fruit (average skin colour score 4.3 (Australian Cherry Guide) and average 15.0 % TSS) were sampled throughout the packing line on 7 December 2011. The different sampling points are described in Table 9.

Table 9. The sampling points of Lapin cherry fruit from Shed 2 Sampling point 1 From the tree Sampling point 2 From the picker’s basket Sampling point 3 From the field tub Sampling point 4 Into bin before hydrocooling Sampling point 5 Before the cluster cutter Sampling point 6 After the cluster cutter Sampling point 7 After pre-sorting Sampling point 8 Before sizing Sampling point 9 After the sizing run Sampling point 10 From the packed box (largest drop) Sampling point 11 From the packed box (smallest drop)

There was no major pitting on fruit that were carefully picked from the tree and immediately stored. The levels of pitting generally increased during the packing process and the results showed that significant pitting occurred in the last part of the packing process (ie from the hand sorting and packing into the box) (Figure 57 and Figure 58). The level of major pitting from the packed box of fruit after four weeks storage at 0oC was over 25% of all fruit (Figure 57). It is interesting to note that there were differences between sampling point 10, which had the maximum drop of 25cm from the belt into the bottom of the box, to sampling point 9, where the drop from the belt was only 7cm. There appears to be a difference in pitting, where the larger drop had higher levels of pitting damage.

Potential major / unacceptable bruising issues were identified after the cluster cutter and pre-sorting (Figure 59).

In addition, the number of rots were highest after the cluster cutter and pre-sorting where fruit rots were 20% of the all the fruit (Figure 60). But the application of postharvest fungicides (Sampling point 9) resulted in no (negligible) fruit with rots after four weeks storage at 0oC. The packing process did not seem to affect the level of stem retention, stem condition / browning (Figure 61), nor the flesh firmness (Figure 62), as all cherries from the different sampling points had similar levels after cold storage.

Shed 2 - Minor Pitting % Shed 2 - Major Pitting % 100 100 90 90 80 80 70 70 60 60 50 50 40 40 30 30 20 20 10 10 Percentage pittedof cherries(%) Percentage pittedof cherries (%) 0 0 initial1 2 3 4 5 6 7 8 9 10 11 initial1 2 3 4 5 6 7 8 9 10 11

Sampling point Sampling point

Figure 57. The percentage of fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 2 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 9.

Shed 2 - Average Minor Pitting Shed 2 - Average Major Pitting 0.6 0.6

0.5 0.5

0.4 0.4

0.3 0.3

cherries 0.2 cherries 0.2

0.1 0.1 Average numberof pits /75 Average numberof pits /75 0 0 initial1 2 3 4 5 6 7 8 9 10 11 initial1 2 3 4 5 6 7 8 9 10 11

Sampling point Sampling point

Figure 58. The average number of pits per cherry fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 2 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 9.

Shed 2 - Minor Bruising % Shed 2 - Major Bruising % 100 100 90 90 80 80 70 70 60 60 50 50 40 40 30 30 20 20 10 10 Percentageof bruisedcherries (%) Percentage bruisedof cherries (%) 0 0 initial1 2 3 4 5 6 7 8 9 10 11 initial1 2 3 4 5 6 7 8 9 10 11

Sampling point Sampling point

Figure 59. The percentage of fruit with minor bruising (acceptable) and major bruising (unacceptable bruising) in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 2 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 9.

Shed 2 - Rots % 100 90 80 70 60 50 40 30 20 10

Percentage rottenof cherries(%) 0 initial1 2 3 4 5 6 7 8 9 10 11

Sampling point

Figure 60. The percentage of fruit with rots in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 2 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 9.

Shed 2 - stems intact % Shed 2 - Stem Score 100 4 90 80 70 3 60 50

(%) 40 2 30 20 10 Stem score condition where 1= 10-25% brown, 4>25% is brown

0 100% green, 2<10% is brown, 3 is 1 Percentagestemmedof cherries initial1 2 3 4 5 6 7 8 9 10 11 initial1 2 3 4 5 6 7 8 9 10 11

Sampling point Sampling point

Figure 61. The percentage of fruit with intact stems (left) and the average stems scores (right) in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 2 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 9.

Shed 2 - Average Firmness 500.00 450.00 400.00 350.00 300.00 250.00 200.00 Firmness(g) 150.00 100.00 50.00 0.00 initial1 2 3 4 5 6 7 8 9 10 11

Sampling point

Figure 62. The average firmness (g/m2) as measured with the FirmTech in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 2 and stored for four weeks at 0oC. (n = 25 fruit). The different sampling points in the line are described in Table 9.

Shed 3 Cherry packingshed 3 was in Young, NSW. Simone cherry fruit (average skin colour score 4.7 (Australian Cherry Guide) and average 13.9% TSS) were sampled throughout the packing line on 7 December 2011. The different sampling points are described in Table 10.

Table 10. The sampling points of Simones cherry fruit from Shed 3 Sampling point 1 From bin from the cool room Sampling point 2 Before the cluster cutter Sampling point 3 After the cluster cutter Sampling point 4 After the sizer Sampling point 5 After the sizing run Sampling point 6 From the flume onto the conveyor Sampling point 7 From the hand sorting conveyor Sampling point 8 From the packed box

The level of major / unacceptable pits in fruit sampled after the sizer was large (>20% of all fruit, excluding sampling point 5). Both major (unacceptable) and minor (acceptable) pitting was high (Figure 63 and Figure 64). The level of bruising was generally low through the packing process, although some damage did occur at the final packing process (sampling points 7 and 8) (Figure 65). The number of rots that developed in stored fruit was high from fruit sampled before the cluster cutter (average 25% of all fruit), but this level decreased to around 5% in the packed box (Figure 66). The packing process did not seem to affect the level of stem retention, stem condition / browning (Figure 67), nor the flesh firmness (Figure 68), as all cherries from the different sampling points had similar levels after cold storage.

Shed 3 - Minor Pitting % Shed 3 - Major Pitting % 100 100 90 90 80 80 70 70 60 60 50 50 40 40

Percentageof cherries (%) 30 Percentageof cherries (%) 30 20 20 10 10 0 0 initial1 2 3 4 5 6 7 8 initial1 2 3 4 5 6 7 8 Sampling point Sampling point Figure 63. The percentage of fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Simones cherry fruit removed from different sampling points in the cherry packing line of Shed 3 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 10.

Shed 3 - Minor Pitting Averages Shed 3 - Major Pitting Averages 0.7 0.45 0.6 0.4 0.35 0.5 0.3 0.4 0.25 0.3 0.2

(/75) (/75)0.15 0.2 0.1 0.1 0.05

Average numberof cherries 0 Average numberof cherries 0 initial 1 2 3 4 5 6 7 8 initial1 2 3 4 5 6 7 8 Sampling point Sampling point Figure 64. The average number of pits per cherry fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Simones cherry fruit removed from different sampling points in the cherry packing line of Shed 3 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 10.

Shed 3 - Minor Bruising % Shed 3 -Major Bruising % 100 100 90 90 80 80 70 70 60 60 50 50 40 40

Percentageof cherries (%) 30 Percentageof cherries (%) 30 20 20 10 10 0 0 initial1 2 3 4 5 6 7 8 initial1 2 3 4 5 6 7 8 Sampling point Sampling point Figure 65. The percentage of fruit with minor bruising (acceptable) and major bruising (unacceptable bruising) in Simones cherry fruit removed from different sampling points in the cherry packing line of Shed 3 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 10.

Shed 3 - Rots % 100 90 80 70 60 50 40 30 20 Percentage cherriesof (%) 10 0 initial1 2 3 4 5 6 7 8 Sampling point Figure 66. The percentage of fruit with rots in Simones cherry fruit removed from different sampling points in the cherry packing line of Shed 3 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 10.

Shed 3 - Stems Intact % Shed 3 - Stem Condition 100 4 90 80 70 3 60

50 ) 40 30 2 is >25%is brown 20 intact intact stems (%) 10 =100% green, 2 <10% brown, 310-25%is brown, 4 0 Averagestem scorewhere 1 1 Percentageof cherries with initial1 2 3 4 5 6 7 8 initial1 2 3 4 5 6 7 8 Sampling point Sampling point Figure 67. The percentage of fruit with intact stems (left) and the average stems scores (right) in Simones cherry fruit removed from different sampling points in the cherry packing line of Shed 3 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 10.

Shed 3 - Firmness 500 450 400 350 300 250 200 150 100 50 0 initial 1 2 3 4 5 6 7 8 Figure 68. The average firmness (g/m2) as measured with the FirmTech in Simones cherry fruit removed from different sampling points in the cherry packing line of Shed 3 and stored for four weeks at 0oC. (n = 25 fruit). The different sampling points in the line are described in Table 10.

Shed 4 Cherry packingshed 4* was in Young, NSW. Vans cherry fruit (average skin colour score 5.3 (Australian Cherry Guide) and average 14.0 % TSS) were sampled throughout the packing line on 7 December 2011. The different sampling points are described in Table 11.

Table 11. The sampling points of Vans cherry fruit from Shed 4* Sampling point 1 From bin from the cool room Sampling point 2 Before the cluster cutter Sampling point 3 After the cluster cutter Sampling point 4 After the sizer Sampling point 5 After the sizing run Sampling point 6 From the flume onto the conveyor Sampling point 7 From the hand sorting conveyor Sampling point 8 From the packed box *This sampling run was conducted on the same packing line as Shed 1, except that this run was conducted with Vans fruit (where as Shed 1 was conducted on Lapin cherries).

This sampling run showed very high levels of both minor and major pitting at all sampling points along the packing line, where 30% of all fruit were unacceptable due to pitting after four weeks storage (Figure 69). Fruit from all sampling points were equally pitted indicating that the packing line itself was not the determinant factor in pitting. These results show the importance of variety in the development of pitting. The levels of bruising increased along the packing line with higher levels in the final sorting and packing stages (Figure 70). The levels of rots after four weeks storage were high in all samples; however the use of the postharvest fungicide in the final stages of packing resulted in 15% rots in the packed box after storage (Figure 71). The packing process did not seem to affect the level of stem retention or stem condition / browning (Figure 72), as all cherries from the different sampling points had similar levels after cold storage.

Shed 4 - Minor Pitting % Shed 4 - Major Pitting % 100 100 90 90 80 80 70 70 60 60 50 50 40 40 30 30 20 20 Percentage cherriesof (%)

Percentage cherriesof (%) 10 10 0 0 initial 1 2 3 4 5 6 7 initial 1 2 3 4 5 6 7 Sampling point Sampling point Figure 69. The percentage of fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Vans cherry fruit removed from different sampling points in the cherry packing line of Shed 4 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 11.

Shed 4 - Minor Bruising % Shed 4 - Major Bruising % 100 100 90 90 80 80 70 70 60 60 50 50 40 40 30 30 20 20 Percentage cherriesof (%) Percentage cherriesof (%) 10 10 0 0 initial 1 2 3 4 5 6 7 initial 1 2 3 4 5 6 7 Sampling point Sampling point

Figure 70. The percentage of fruit with minor bruising (acceptable) and major bruising (unacceptable bruising) in Vans cherry fruit removed from different sampling points in the cherry packing line of Shed 4 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 11.

Shed 4 - Rots % 100 90 80 70 60 50 40 30 20 Percentage cherriesof (%) 10 0 initial 1 2 3 4 5 6 7 Sampling point Figure 71. The percentage of fruit with rots in Vans cherry fruit removed from different sampling points in the cherry packing line of Shed 4 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 11.

Shed 4 - Stems intact % Shed 4 - Ave Stem Score 100 4 90 80 70 3 60 50 40

30 2>25%brown

20 10-25%brown, 4 is Percentage cherriesof (%) 10 Stem Score where1= 100% green, 2<10% is brown, 3 is 0 1 initial 1 2 3 4 5 6 7 initial 1 2 3 4 5 6 7 Sampling point Sampling point Figure 72. The percentage of fruit with intact stems (left) and the average stems scores (right) in Vans cherry fruit removed from different sampling points in the cherry packing line of Shed 4 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 11.

Shed 5

Cherry packingshed 5 from Orange, NSW was sampled on 18 January 2012. The different sampling points are described in Table 12.

Table 12. The sampling points of Sweet Georgia cherry fruit from Shed 5 Sampling point 1 From bin from the cool room Sampling point 2 From conveyor after fruit transfer Sampling point 3 Before the cluster cutter Sampling point 4 After the cluster cutter Sampling point 5 After the sizing run Sampling point 6 From the flume onto the conveyor Sampling point 7 From the hand sorting conveyor Sampling point 8 From the packed box (28mm) Sampling point 9 From the re-packed box (28mm)

The levels of acceptable (minor) and unacceptable (major) pitting was relatively constant across the sampling points, while the last packing process resulted in a large increase in major pitting. The levels of major pitting increased from 12% to 32% and the average number of pits per fruit increased four fold (Figure 73 and 74) which was due to re-packing and manual handling of the fruit at this last stage. This was where the already packed 5kg fruit were re-packed into 2kg boxes. This re-packing step was necessary to meet the commercial market expectations for that particular batch of fruit, and was not a regular part of the growers packing regime. However this does highlight the negative effects of excessive handling and manual packing on the development of pitting and fruit quality. The level of bruising was also an issue, which also increased during the hand sorting and packing (Figure 75). The number of rots in stored fruit was higher from the fruit sourced during the initial stages of packing (Figure 76), but these levels decreased due to the use of postharvest fungicide and during sorting indicating the crucial role of fungicides and the manual sorters / packers in selecting sound quality fruit for packing. The packing process did not seem to affect the level of stem retention, stem condition / browning (Figure 77), nor the flesh firmness (Figure 78), as all cherries from the different sampling points had similar levels after cold storage.

Shed 5 - Minor Pitting % Shed 5 - Major Pitting % 100 100 90 90 80 80 70 70 60 60 50 50 40 40 affected(%) 30 affected(%) 30 20 20 Percentageof cherries Percentageof cherries 10 10 0 0 initial1 2 3 4 5 6 7 8 9 initial1 2 3 4 5 6 7 8 9 Sampling point Sampling point Figure 73. The percentage of fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Sweet Georgia cherry fruit removed from different sampling points in the cherry packing line of Shed 5 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 12.

Shed 5 - Ave Minor Pitting Shed 5 - Ave Major Pitting 1 1 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4 0.4

0.3 affected (/75) 0.3 affected (/75)0.2 0.2 0.1 0.1 Ave Number cherriesof 0 Average numberof cherries 0 initial1 2 3 4 5 6 7 8 9 initial1 2 3 4 5 6 7 8 9 Sampling point Sampling point Figure 74. The average number of pits per cherry fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Sweet Georgia cherry fruit removed from different sampling points in the cherry packing line of Shed 5 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 12.

Shed 5 - Minor Bruising % Shed 5 - Major Bruising % 100 100 90 90 80 80 70 70 60 60 50 50 40 40 affected(%) 30 affected(%) 30 20 20 Percentageof cherries Percentageof cherries 10 10 0 0 initial1 2 3 4 5 6 7 8 9 initial1 2 3 4 5 6 7 8 9 Sampling point Sampling point Figure 75. The percentage of fruit with minor bruising (acceptable) and major bruising (unacceptable bruising) in Sweet Georgia cherry fruit removed from different sampling points in the cherry packing line of Shed 5 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 12.

Shed 5 - Rots % 100 90 80 70 60 50 40 affected(%) 30 20 Percentageof cherries 10 0 initial1 2 3 4 5 6 7 8 9 Sampling point Figure 76. The percentage of fruit with rots in Sweet Georgia cherry fruit removed from different sampling points in the cherry packing line of Shed 5 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 12.

Shed 5 - Stems intact % Shed 5 - Ave Stem Scores 100 4 90 80 70 3 60 50 40

stems (%) 2

30 >25%is brown 20

10 1=100% green, 2<10% is Average stem wherescores brown, 310-25% is brown, 4 Percentage cherriesof with 0 1 initial1 2 3 4 5 6 7 8 9 initial1 2 3 4 5 6 7 8 9 Sampling point Sampling point Figure 77. The percentage of fruit with intact stems (left) and the average stems scores (right) in Sweet Georgia cherry fruit removed from different sampling points in the cherry packing line of Shed 5 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 12.

Shed 5 - Firmness 500 450 400 350 300 250 200 Firmness (g) 150 100 50 0 initial1 2 3 4 5 6 7 8 9 Sampling point Figure 78. The average firmness (g/m2) as measured with the FirmTech in Sweet Georgia cherry fruit removed from different sampling points in the cherry packing line of Shed 5 and stored for four weeks at 0oC. (n = 25 fruit). The different sampling points in the line are described in Table 12.

Shed 6

Cherry packingshed 6 from the Adelaide Hills, SA. Lapin cherry fruit (average skin colour score 5.9 (Australian Cherry Guide) and average 17.5% TSS) were sampled throughout the packing line on 19 December 2011. The different sampling points are described in Table 13.

Table 13. The sampling points of Lapin cherry fruit from Shed 6 Sampling point 1 Cold store Sampling point 2 Start of line Sampling point 3 Water dump Sampling point 4 After cluster cutter Sampling point 5 Size conveyor Sampling point 6 Hand sort Sampling point 7 Prior to pack

Although the number of pits per pitted cherry remained the same across all the sampling points, the level of unacceptable major pits increased after the cluster cutter, whereby the level of major pits after four weeks storage, in fruit prior to packing was 80% (Figure 79 and Figure 80). The levels of bruised fruit was low, but the number of rots in fruit stored for four weeks was high (Figure 81). This was particularly noted in fruit after the water dump. However the sorting and use of postharvest fungicide resulted in rots of around 10% after cold storage.

Figure 79. The percentage of fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 6 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 13.

Figure 80. The average number of pits per fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 6 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 13.

Figure 81. The percentage of fruit with major bruising (unacceptable bruising) and rots in Lapin cherry fruit removed from different sampling points in the cherry packing line of Shed 6 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 13.

Shed 7

Cherry packingshed 7 from the Adelaide Hills. Stella cherry fruit (average skin colour score 4.5 (Australian Cherry Guide) and average 18% TSS) were sampled throughout the packing line on 20 December 2011. The different sampling points are described in Table 14.

Table 14. The sampling points of Stella cherry fruit from Shed 7 Sampling point 1 Cold store Sampling point 2 Start of line Sampling point 3 Water dump Sampling point 4 After cluster cutter Sampling point 5 Size conveyor Sampling point 6 Hand sort Sampling point 7 Prior to pack

The results showed that the level of unacceptable pitting particularly increased after the cluster cutter, whereby in the packed fruit stored for four weeks at 0oC resulted in 60% of all fruit having significant major pitting and all steps along the packing process having high levels of pitting (Figure 82). The average number of pits per pitted fruit remained relatively constant over the sampling points (Figure 83). The levels of bruised fruit gradually increased along the packing line, whereby at the end of the line the packed fruit was nearly 30% bruised (Figure 84). The level of rots assessed after the four weeks storage were also high, with over 10% of all fruit having postharvest rots.

Figure 82. The percentage of fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Stella cherry fruit removed from different sampling points in the cherry packing line of Shed 7 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 14.

Figure 83. The average number of pits per fruit with minor pitting (2-5mm in diameter) and major pitting (>5mm in diameter) in Stella cherry fruit removed from different sampling points in the cherry packing line of Shed 7 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 14.

Figure 84. The percentage of fruit with major bruising (unacceptable bruising) and rots in Stella cherry fruit removed from different sampling points in the cherry packing line of Shed 7 and stored for four weeks at 0oC. The different sampling points in the line are described in Table 14.

Correlation between impact and fruit damage In a preliminary attempt to correlate the potential fruit damage (such as pitting) with drop height of the fruit onto a hard surface, a small demonstration trial was conducted. Regina cherries of two maturities were sourced: (1) Immature - red, Average skin colour score 3.7 (Australian Cherry Guide), TSS 13.8%; and (2) Mature - dark, Average skin colour score 5.6 (Australian Cherry Guide), TSS 14.2% (Figure C).

Ten fruit with core temperatures of 5oC and 20oC) were dropped from two different heights (5cm and 10cm) (Figure 85) and stored at 0oC for two weeks before assessment of pitting and fruit damage.

Figure 85. Testing Regina cherry fruit of different maturities (mature and immature) at different drop heights and fruit temperatures for inducing pitting damage after storage.

There were differences in fruit firmness between the different fruit maturities (Table 15), but the data showed that there was no impact damage to any of the fruit at either harvest maturity, fruit temperature or drop height. There was no pitting or bruising on any fruit suggesting that this variety, the season, or the treatments were not severe enough to induce pitting.

Table 15. Fruit firmness (g/mm2) of Regina cherries at two drop temperatures and two harvest maturities after two weeks storage at 0oC.

5oC 20oC

Drop Maturity Maturity Height Dark Red Dark Red

0 309 351 320 345

5 cm 305 357 293 328

10 cm 308 369 293 334

Current research by Dr. Juan Pablo Zoffoli at the Pontificia Universidad Católica in Chile is developing predictive tools to sort and predict the effects of mechanical damage during storage. Dr. Zoffoli presented this work at the 7th International Postharvest Conference in Malaysia in June 2012. They have been working with seven different varieties over two seasons. Their research has shown that the percentage deformation is the best parameter for enabling the characterisation of the cherry fruit to mechanical damage. This line of research will assist in better understanding mechanical damage which will lead to better ways to manage and reduce this damage to cherry fruit.

Juan Pablo Zoffoli, Javier Jauregui and Chris Hanssens (2012) ‘Characterization of mechanical injury to sweet cherry cultivars’ Pontificia Universidad Católica, Chile. 7th International Postharvest Conference. 25-29 June 2012.

Discussion

As this study was solely focussed on the domestic retail situation, there was little emphasis on storage of fruit. However when Australia develops its export markets, storage issues such as those identified in this study – pitting, bruising and rots, will becoming increasingly important. This preliminary study examined the potential causes of the downgrading of fruit quality caused by picking and packing. Note that this was only a preliminary survey and more packing lines with a systematic investigation of varieties in different growing areas are required to identify and quantify fruit quality issues. In this study, seven different packing lines / variety combinations were assessed in the 2011/12 season in Young, Orange, and the Adelaide Hills. Critical points in the harvest / packing lines were assessed where fruit were removed from the line, stored for four weeks at 0oC then assessed for fruit quality. The results showed that there were large differences in the occurrence of pitting among different sheds. This maybe due to preharvest and cherry variety factors, but it does appear there is room for significant improvement in cherry fruit packing to optimise fruit quality. The individual results of the different sheds will be discussed with the individual packingshed operators so improvements can be made. The results clearly showed that the picking and packing operations can have a significant effect on fruit quality and in particular pitting. The results identified some common problem packing areas that need addressing:

Hand sorting and packing In this study, the final stage of packing appears to be critical in determining final product quality and any potential damage should be able to be reduced or managed with minor line modifications, such as lowering drops onto conveyors or the addition of padded cushions. In addition, improved education and training of workers on the correct and consistent handling / sorting of fruit will also help improve fruit quality.

Cluster cutters Cluster cutters also appear to be an issue in the development of pitting. These have been consistently identified by other studies to contribute to pitting (Grant and Thompson, 1997). This brief survey did not examine the role of packing line speed eg cluster cutter belt speed. However Grant and Thompson (1997) showed that lowering the cluster cutter speed reduced pitting.

General handling, grading and sorting There appears to be significant general impact damage to fruit occurring in all parts of the packing line and there are some well known practical things to do to reduce this impact and fruit damage. These include reducing the number and height of fruit

97 drops to hard surfaces, or cushioning these drops, at equipment transitions. Even though all transitions and movements use water flumes in place of conveyor belts, there are still significant impacts with cutters, graders and conveyors which should be minimised.

Variety The effect of cherry variety on fruit pitting after harvest is crucial. This was well illustrated in this survey when comparing the results of Packing line 1 and 4. These were the same sheds but packing different varieties of cherries from the same orchard. The results clearly showed that the Vans cherry fruit packed (results from Shed 4) had significantly more pitting after storage than the Lapin fruit (results from Shed 1).

Several models have been investigated to relate fruit characteristics such as (fruit firmness at harvest, fruit respiration at harvest, and weight loss in storage) to the severity of pitting (Toivonen et al., 2004). In this preliminary study of the effects of drop height on pitting in Regina fruit showed no pitting with any damage, but more work is required to investigate this. It appears that there are likely unmeasured variables involved in determining susceptibility to pitting (Toivonen et al., 2004). However the recent work of Dr. Juan Pablo Zoffoli at the Pontificia Universidad Católica in Chile shows some promise and should be applied to Australian conditions.

The need for the Australian cherry industry to shift its focus to exports will necessitate the importance of market access and postharvest quality. Managing fruit pitting will become an increasing important aspect of storage and fruit quality for Australian cherry exports and strategies must be implemented to ensure pitting and bruising are not barriers to the growth of the Australian cherry industry.

4. Managing fruit and stem quality after the packinghouse

Cherry fruit are a perishable product and quality deteriorates after harvest. Water loss from the fruit results in stem browning and shrivel and fruit softening. In addition, as most cherry fruit are sold by weight, loss of water (and the development of rots) during postharvest handling and marketing incurs a direct financial loss. To maintain fruit quality and manage water loss from the fruit, it is important to appreciate the factors that drive water loss from the fruit. The potential for water loss is directly related to the vapour pressure deficits (VPD) experienced by the fruit during handling and storage.

Background and concepts

Relative humidity (RH) Humidity is the general term referring to the presence of water vapour in air. Relative humidity is defined as the ratio of the water vapour pressure in the air to the saturation vapour pressure possible at the same temperature, and is expressed as a percentage (%).The RH of saturated air is 100%.

Vapour pressure (VP) If pure water is placed in an enclosure containing dry air, water molecules will enter the vapour phase until the air becomes saturated with water vapour. The pressure that these molecules exert on the container walls is the vapour pressure (VP). The amount of water vapour in atmospheric air is dependent on temperature and pressure. For example, saturated air at 30°C contai ns approximately 30.4 g water/ m3 of air and the VP is about 4.25 kPa. The water potential of air is related to the RH by the following logarithmic relationship: –Ψwv = (RT/Vw) x ln(RH%/100) where, ΨWV is water potential of water vapour, VW is the molar volume of water (e.g. 0.000018048 m3/mol. at 20°C), R is the gas constant, T is the abs olute temperature. The water potential of air is usually low relative to that of harvested horticultural produce (e.g. –14.2 MPa at 90% RH and –93.6 MPa at 50% RH; 20°C).

The relationship between the various properties (e.g. wet bulb and dry bulb temperatures, water vapour pressure) of moist air is illustrated in psychometric charts (Figure 86). These are a diagrammatic representation of the physical and thermal characteristics of atmospheric air at constant barometric pressure. The scale along the bottom axis indicates dry bulb temperatures as given by a wet- and-dry bulb hygrometer. At all temperatures, dry air has no water and, therefore, a

water vapour pressure of zero. The curved line at the top illustrates the relationship between VP and temperature in saturated air, and is the line of 100% RH. Other curved lines can be drawn representing constant RH over a range of temperatures. The curvature of these lines shows that the VP of water increases rapidly with temperature.

Figure 86. Simplified psychrometric chart

Vapour pressure deficit (VPD) The difference between the VP of the produce, which is a function of temperature and that of the surrounding air, is called the vapour pressure deficit (VPD). VPD calculations can be used to compare relative rates of water loss under different sets of conditions. In practice the vapour pressure of water in fresh produce (the effective RH) is less than that of pure water at the same temperature due to the reduction in water activity caused by dissolved sugars, acids and salts in the cells.

Factors affecting water loss (transpiration) from cherry fruit Water vapour moves from an area of high relative humidity (high VP) to one of low relative humidity (low VP). The greater the difference in humidity (VPD), the faster water moves. This factor is important because the rate of water movement directly determines the transpiration rate of the fruit.

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The transpiration rate of the fruit is determined by the environment in which the fruit is stored. Temperature, RH and air flow around fruit affect the transpiration rate from the stored product. Transpiration generally is quite slow when temperatures are cool, RH is high, and there is no wind. This will be examined in the later part of this Section.

Cherry fruit are covered by a natural waxy layer of cutin secreted over the epidermis. This hydrophobic or water repellent layer protects the fruit from dry environments in the orchard and during storage and handling. Wax is often arranged as platelets on the surface of the skin. Well-ordered overlapping platelets or continuous wax provides considerable resistance to permeation of water vapour. However any mechanical damage (such as pitting and bruising) may increase water loss by rupturing the natural barriers (waxy cuticle and suberised outer cell layers). Coating fruit with wax formulations is used commercially to reduce water loss in other horticultural crops and its application to cherry fruit will be examined and discussed in Section 4.4.

This Section will describe: 4.1. A pilot survey of the physical retail display environment in a supermarket fruit and vegetable section and an independent fruit and vegetable store, 4.2. A series of experiments to examine the effect of temperature, relative humidity and flow rates in display environment on cherry fruit and stem condition and water loss, 4.3. Preliminary investigations into packaging types to evaluate different packaging types (punnets, open bags, and open display) on fruit and stem quality after a simulated retail life, and 4.4. Preliminary investigations into a range of coatings to maintain fruit and stem quality and freshness during storage and retail display.

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4.1 Preliminary survey of cherry retail display conditions

Background and Methods The final stage in the supply chain of cherries to the consumer is the retail display. This is an important aspect of the cherry supply chain as the conditions in which cherry fruit are displayed in the retail environment can affect final fruit quality presented to the consumer. A preliminary survey of the physical conditions of the retail display in the store where the cherry fruit is displayed was conducted in one supermarket and one independent fruit and vegetable store in February and March 2012. The cherry fruit were on display in the specialised refrigerated cabinet in the supermarket, whilst in the independent fruit and vegetable store the cherries were in the refrigerated wall cabinet. Data loggers were placed around the cherry fruit at these locations. These data loggers were placed in similar positions in the other locations where cherry fruit might be displayed in each store. 1. Supermarket fruit and vegetable displays In the supermarket fruit and vegetable section, the display temperature and relative humidity were monitored every 15 minutes with calibrated Tiny Tag data loggers in different display types: 1a) specialised refrigerated table, 1b) refrigerated wall cabinet, 1c) ambient retail conditions with fruit and 1d) general ambient conditions Air flow was recorded at the refrigeration outlet, inlet and over the produce using a wind anemometer (Thermal anemometer, Kimo Instruments VT100). This preliminary survey was conducted on 3 February 2012 between 7.30am and 1pm.

2. Independent fruit and vegetable store displays In the independent fruit and vegetable store, the display temperature and relative humidity were monitored every 15 minutes with calibrated Tiny Tag data loggers in different display types: 2a) refrigerated wall cabinet, and 2b) general ambient conditions Although this store is air conditioned, the entire front of the store opens onto a covered west-facing veranda. This survey was conducted from 25 February to 12 March 2012.

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Results Supermarket

1a) Specialised refrigerated table The location of the temperature and relative humidity logger in the specialised refrigerated display table in the supermarket is shown in Figure 87. The cherries were displayed in an open bulk display on the refrigerated table.

Figure 87. Layout and location of temperature and relative humidity logger in the refrigerated table in the supermarket

The temperature (green) and relative humidity (blue) recorded in the cherry fruit at this location within the specialised refrigerated table is presented in Figure 88. The logger was placed into the fruit display at 7.30am and removed at 1pm. The results show that the fruit were subject to display temperatures ranging from 0 to 3oC and 70-80% relative humidity.

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Figure 88. Temperature (green) and relative humidity (blue) recorded in the cherry fruit at this location within the specialised refrigerated table

Table 16. Summary statistics for the specialised refrigerated table in the supermarket between 8.30am and 12.30pm (after equalisation).

Temperature (oC) Relative humidity (%)

Minimum -0.7 60.1

Maximum 3.4 93.6

Average 1.9 77.5

The average wind speed of the specialised refrigerated table from the: inlet 0.24 – 0.31 meters.sec-1 (m.s-1) outlet 0.23 m.s-1 around produce 0.24 - 0.31 m.s-1

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1b) Refrigerated wall cabinet The location of the temperature and relative humidity logger in the refrigerated wall cabinet in the supermarket is shown in Figure 89.

Figure 89. Layout and location of the temperature and relative humidity logger in the refrigerated wall cabinet in the supermarket

The temperature (green) and relative humidity (blue) recorded near cabbages on the second to top shelf in the refrigerated wall cabinet is presented in Figure 90. The logger was placed onto the display at 7.30am and removed at 1pm. The results show that the logger recorded display temperatures of around 5oC and 90% relative humidity.

Figure 90. Temperature (green) and relative humidity (blue) recorded in the cherry fruit at this location within refrigerated wall cabinet in the supermarket.

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Table 17. Summary statistics for the refrigerated wall cabinet in the supermarket between 8.30am and 12.30pm (after equalisation).

Temperature (oC) Relative humidity (%)

Minimum 4.5 87.9

Maximum 11.1 100

Average 5.8 92.7

The average wind speed from the refrigerated wall cabinet: inlet 0.34 - 0.67 m.s-1 outlet 0.29 - 0.44 m.s-1 around produce 0.23 - 0.41 m.s-1

1c) Ambient retail conditions (with fruit) The location of the temperature and relative humidity logger in the ambient fruit display in the supermarket is shown in Figure 91. There were no cherries on ambient display on this occasion, and table grapes were used as the representative fruit.

Figure 91. Layout and location of the temperature and relative humidity logger in the ambient fruit display in the supermarket.

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The temperature (green) and relative humidity (blue) recorded in the table grapes in an ambient display is presented in Figure 92. The logger was placed into the fruit display at 7.30am and removed at 1pm. The table grapes were freshly stocked from the cool room onto the display. The results show that the average temperature of the table grapes at ambient display was 17oC and the average relative humidity of the display was 89% relative humidity. This was similar to the natural ambient temperatures as measured in the next section.

Figure 92. Temperature (green) and relative humidity (blue) recorded in the table grapes in an ambient display

Table 18. Summary statistics in the ambient fruit display (table grapes) in the supermarket between 8.30am and 12.30pm (after equalisation).

Temperature (oC) Relative humidity (%)

Minimum 16.5 74.4

Maximum 18.2 94.2

Average 17.0 88.7

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1d) General ambient conditions The location of the temperature and relative humidity logger in the general fruit and vegetable section of the supermarket was near the citrus display (Figure 93).

Figure 93. Layout and location of the temperature and relative humidity logger in the general fruit and vegetable section of the supermarket

The temperature (green) and relative humidity (blue) recorded as an ambient display (Figure 94). The logger was placed into the fruit display at 7.30am and removed at 1pm. The results show that the temperature in the general retail environment of the fruit and vegetable section of the supermarket was around 19oC and 70% relative humidity.

Figure 94. Temperature (green) and relative humidity (blue) recorded as an ambient display in the supermarket.

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Table 19. Summary statistics in the ambient conditions within the fruit and vegetable section in the supermarket between 8.30am and 12.30pm (after equalisation).

Temperature (oC) Relative humidity (%)

Minimum 17.9 66.3

Maximum 19.6 73.4

Average 18.7 69.9

Results. Independent Fruit and Vegetable Store 2a) Refrigerated wall cabinet The location of the temperature and relative humidity logger in the refrigerated wall cabinet display of the independent fruit and vegetable store is shown in Figure 95.

Figure 95. Layout and location of the temperature and relative humidity logger in the refrigerated wall cabinet display of the independent fruit and vegetable store.

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The temperature and relative humidity recorded near table grape display on the top shelf (top graph) and second shelf (lower graph) in the refrigerated wall cabinet is presented in Figure 96 and Figure 97. This the regular position of the cherry display in this store. The graphs show the display over the sixteen days of the survey, and illustrate the relatively consistent daily temperature and relative humidity cycles. The difference between the average temperature and relative humidity of the logger measurements on the top shelf and second shelf was 0.7oC and 2.4% relative humidity.

Figure 96. Temperatures (green) and relative humidity (blue) measurements from 25 February to 12 March 2012 on the top shelf in the refrigerated wall cabinet of an independent fruit and vegetable store.

Figure 97. Temperatures (green) and relative humidity (blue) measurements from 25 February to 12 March 2012 on the second shelf in the refrigerated wall cabinet of an independent fruit and vegetable store.

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Table 20. Summary statistics for refrigerated wall cabinet of an independent fruit and vegetable store surveyed from 25 February to 12 March 2012.

Top shelf Second shelf

Temperature Relative Temperature Relative (oC) humidity (%) (oC) humidity (%)

Minimum 6.8 79.5 7.6 77.2

Maximum* 18.4 100 17.6 100

Average 10.3 98.7 11.0 96.3

* The average temperatures experienced in the refrigerated wall cabinets in the independent fruit and vegetable store in the table above are misleading as they include significant overnight defrost periods – see Figure 96 and Figure 97.

Comparison of a single day refrigerated wall cabinet measurements Typical daily temperature and relative humidity measurements recorded near the table grape display on the top shelf and second shelf in the refrigerated wall cabinet are presented in Figure 98 and Figure 99 respectively. These graphs illustrate a typical daily cycle of temperatures and relative humidity. The results show that the logger recorded display temperatures between 7 to 10oC and 88-100% relative humidity. However there were three large defrost cycles (each up to 2 hours duration) in the refrigerated cabinets during the evening / early morning, where the temperatures increased to 16oC.

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Figure 98. Temperatures (green) and relative humidity (blue)measurements from 5 March (6pm) to 6 March (6pm) on the top shelf in the refrigerated wall cabinet of an independent fruit and vegetable store.

Figure 99. Temperatures (green) and relative humidity (blue) measurements from 5 March (6pm) to 6 March (6pm) on the second shelf in the refrigerated wall cabinet of an independent fruit and vegetable store.

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2b) General ambient conditions The location of the temperature and relative humidity logger in ambient display of the independent fruit and vegetable store is shown in Figure 100.

Figure 100. Layout and location of the temperature and relative humidity logger in ambient display of the independent fruit and vegetable.

The temperature (green) and relative humidity (blue) recorded in an ambient display from 28 February to 12 March 2012 in an independent fruit and vegetable store are illustrated Figure 101. The average temperature in the store during this sampling period was 19.7oC with a maximum temperature within the ambient retail environment was 25.5oC (RH 71%).

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Figure 101. Temperature (green) and relative humidity (blue) recorded in an ambient display from 28 February to 12 March 2012 in an independent fruit and vegetable store

Table 21. Summary statistics for the ambient temperature within an independent fruit and vegetable store surveyed from 25 February to 12 March 2012. The local Bureau of Meteorology data (Gosford) from the same sampling period is also shown.

In-store ambient display Gosford BOM

Temperature Relative Temperature Relative (oC) humidity (%) (oC) humidity (%)

Minimum 16.1 53.0 13.0 40.0

Maximum 25.5 94.8 32.3 100

Average 19.7 72.9

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Comparison of a single day ambient measurements As a representative day of the sampling period, the temperatures and relative humidity measurements from 5 March (6pm) to 6 March (6pm) in an ambient display is presented in Figure 102. The maximum ambient temperature within the store on this day was 22.9oC. To put these results in context, the outside temperature was a maximum of 23.6oC. This shows that the outside temperature affects the ambient conditions within this store. Even though the store has air conditioning, it has a large shop front which allows the movement of air and heat to the atmosphere.

Figure 102. Temperatures (blue) and relative humidity (green) measurements from 5 March (6pm) to 6 March (6pm) in an ambient display in an independent fruit and vegetable store.

Table 22. Summary statistics for the ambient temperature within an independent fruit and vegetable store surveyed for a representative day (5 March (6pm) to 6 March (6pm)). The local Bureau of Meteorology data (Gosford) from the same day is also presented.

Ambient store display Local BOM (Gosford)

Temperature Relative Temperature Relative (oC) humidity (%) (oC) humidity (%)

Minimum 18.3 89 16.7 77

Maximum 22.9 62 23.6 90

Average 20.3 73

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Discussion

The marketing of cherry fruit at the retail environment must not only take into account the need to sell cherries at a premium price, but appreciate that cherry fruit are a high quality product which are very sensitive to temperature and relative humidity abuses. High quality fruit can rapidly deteriorate due to poor storage and display conditions. This is examined in more detail in Section 4.2. This preliminary survey measured the temperature and relative humidity display conditions in supermarket and independent fruit and vegetable store. The results showed the fruit on display in both the supermarket and independent fruit and vegetable store could be subject to a wide range of temperatures and relative humidities resulting in large vapour pressure deficits (VPD) between the cherry fruit and the display environment, depending on their display position within the store. It should be noted that this preliminary survey was a snap shot of the supermarket display conditions as it was only conducted in one store on one morning / afternoon on 3 February 2012. It does not reflect the overall daily / weekly conditions, or other stores. But these observations do illustrate the ranges of conditions experienced by cherries in the market place. The supermarket specialist refrigerated table provided the best presentation condition to maintain cherry fruit and stem quality. The display low temperatures (average 2oC and 77% relative humidity) resulted in low VP (637Pa) which is excellent in a commercial situation and still allowed consumers to select fruit from a bulk display. Low VPD is the key to maintaining high quality fruit during storage and retail display. The refrigerated wall displays cabinets also assist in maintaining fruit quality. The average temperature in the wall display in the supermarket was 6oC, 92%RH (VP 898Pa), whilst the independent fruit and vegetable store’s refrigerated wall display ranged from 7-10oC with 88-100%RH (VP 941 to 1,227Pa). Cherry fruit are often exposed to the ambient environment, especially in the peak of the season when they are displayed in large unrefrigerated open displays. Extra care and attention must be paid to maintaining cherry fruit quality when the fruit is displayed at room temperature due to the large VPD generated leading to rapid water loss and deterioration in fruit quality. The average temperature in the air conditioned supermarket was 19oC with 70%RH (VP 1,766Pa), whilst in the independent fruit and vegetable store which was completely open to the outside environment, was 20oC with RH 73% (VP 1,916). However at times during the February – March 2012, the ambient temperature within the independent fruit and vegetable store reached 26oC with RH 71%. This is equivalent to VP of 2,574Pa. High VPD are not recommended for storage of cherries. The open ambient display is only satisfactory when the fruit can be rapidly sold and have high turnover of stock where the fruit are not held for long periods of time. The high display temperatures stimulate the development of any latent rots in the fruit and also result in dry / brown the stems (see Section 4.2).

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These observations also show that is important not to assume that these display conditions are constant due to varying conditions such as refrigeration defrost cycles during the day and night and that these changing conditions must be managed to minimise their negative impacts on fruit quality. This was particularly noted in the independent fruit and vegetable store, where the there were three large defrost cycles (each up to 2 hours duration) in the refrigerated cabinets during the evening / early morning. During these defrost cycles the inlet temperatures increased up to 16oC and RH 85% generating a VP 1,647Pa. This is a very high VP and will result in significant water loss from the fruit. After defrosting, refrigeration system returns to the set-point 7-10oC with 88-100%RH (VP 941 to 1,227Pa). These large and consistent fluctuations in VP during the day / night not only results in high VPD, but would result in the condensation of free water on the surface of the fruit. This condensation can promote rots (ie. spore germination), fruit softening and accelerate warming of the produce (ie. latent heat of vaporization release, high thermal conductivity). The huge fluctuations air temperatures during the defrost cycles as observed in the independent fruit and vegetable store must be avoided. It was unfortunate that this pilot survey did not obtain more data (daily / weekly) from the supermarket, as this may have identified refrigeration issues that may affect final product quality. It should also be noted that even under conditions of low storage temperature (eg 0oC) and high RH (eg 95% RH), extremely small fluctuations in temperature (< 0.5oC) can result in condensation on cooling surfaces. This is why cherry fruit are often packed with an absorbent pad within the plastic liner of packed fruit before storage and transport.

Another important and often neglected aspect of the retail environment is the handling and storage of the fruit after the store has closed. As the display conditions in the store can vary, it is important to maintain low temperatures and high relative humidity around the fruit for as long as possible. For example, if the fruit is in an open display, the fruit must be covered and moved into refrigeration after the store has closed. The use of packaging also significantly assists in maintaining high relative humidity around the fruit. This will be examined and discussed in Section 4.3.

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4.2 Effect of storage conditions on cherry stem browning

At the retail stage, changes in fruit appearance (colour, gloss, surface pitting), fruit softening, and stem browning and dehydration are major symptoms of quality loss. Under current marketing conditions, the appearance of cherry stems greatly influences consumer perception of cherry quality (Drake et al., 1991). Cherry stems have a much thinner epidermis and cuticle layer than the fruit itself, resulting in a higher sensitivity to water and carbon dioxide losses (Sekse, 1996, 1988). Therefore green stems are often used as indicators of overall cherry fruit freshness. These sorts of indicators are very helpful and important for consumers to guide their buying decisions (Linke et al., 2010).

Background The retail survey from 2010/11 season (Section 1) showed that stem browning at the retail level was a significant issue. The results showed that stem browning significantly increased during the time on retail display, and this was apparently relatively independent on the type of display (refrigerated and ambient display). As the temperature of the display environment did not seem to slow the rate of stem deterioration, it is proposed that the water loss from the stem due to the vapour pressure deficit (VDP) is the main driver of water loss and stem browning. The main factors controlling VDP is storage temperature and relative humidity of the storage environment. These storage trials examined the effect of different storage temperatures, RH and air flow rates on stem browning and water loss.

Aim Determine the effects of different storage temperature, RH and air flow rate on cherry fruit and stem condition.

Methods A series of storage experiments were conducted on: (1) fruit with their stems attached, and (2) stems which had been detached from the fruit. Commercially mature fruit were sourced from orchards in NSW and Tasmania.

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1. Stem quality with the fruit removed. This experiment was repeated (replicated) three times using different varieties (Sweetheart, Stella, Sweet Georgia) for each repetition. Cherry stems were removed from the fruit and randomly allocated treatments. For each treatment, there were four replicates with each unit contained ten stems. 2. Fruit with stems attached. This experiment was repeated (replicated) twice using different varieties (Sweetheart, Sweet Georgia) for each repetition. For each treatment, there were four replicates with each unit contained six fruit.

Fruit with stems attached (six fruit) or stems alone (ten stems) were sealed in a 2L glass jar and stored at either 5oC or 20oC. The stems / fruit were subject to two relative humidity treatments (70% and 100%RH) using a flow through system with flow rates of 25, 50 and 100 mL air per minute. The vapour pressures of the different temperatures and RH are presented in Table 32.

Table 32. Vapour pressures (Pa) of the different storage environments under static conditions*

Relative Humidity (%)

70% 100%

Temperature 5oC 751 872 (oC) 20oC 1,871 2,337

* Note that the different flow rates tested in these experiments (25, 50 and 100 mL/min) also significantly affect transpiration rates

A manometer flow board for each RH and temperature supplied the different flow rates for each treatment (Figure 103). A static control chamber for each humidity acted as the 0 mL per minute treatment. The 70% RH chamber was generated by preparing a saturated NaCl solution, whilst the 100% RH chamber was generated using distilled water as the source of water vapour (Figure 104). Each of the 16 treatment units was replicated four times for each experiment. Each treatment unit was allocated using the DigGer program. An example of the unique design for each temperature for each experiment is presented in Figure 105. The experiments were terminated after two days of treatment / storage.

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Figure 103. Setup showing manometer flow boards on the table in the image (left) for different relative humidities and flow rates (left). Cherry fruit with stems attached (top right) and stems alone (bottom right) sealed in jars for treatment and storage.

Figure 104. Set up for the 0 mL / min treatments in a static system. The ballast solution was saturated NaCl for the 70%RH treatment and water for the 100% RH treatment.

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1 2 3 4Range 5 6 7 8

1 8 3 7 1 5 2 4 6

2 4 2 6 5 7 8 1 3 Row 3 3 4 5 8 2 7 6 1

4 7 1 2 6 8 4 3 5

Figure 105. Example of the experimental design for each treatment allocated using the DigGer program. There were eight treatments (2 RH x 4 flow rates) replicated four times at each temperature. A unique design was used for each treatment temperature, cherry variety and experiment.

A sub-sample of four replicates of ten fruit was measured at Time Zero, ie before storage, and the % water content determined. Time Zero measurements of stem and fruit quality were taken immediately before treatment. Storage and treatment occurred for two days before the stems / fruit were destructively assessed.

Stem quality assessment Each stem was subjectively assessed for stem brownness / greenness (Figure 1); 1 – bright green, 2- <10% brown, 3 – 10-25% brown, 4 - >25% brown stem. Stem freshness; 1 – stem full and plump, 2 – some notable water loss, 3 – unacceptable, significant water loss, 4 – fully dry Stem diameter was measured on all stems before and after treatment and storage. The mid-stem diameter was recorded using a hand micrometer.

Fresh weights of each treatment unit (ten stems) were recorded before and after treatment. Dry weights were then determined to calculate the % water loss from each treatment unit.

Fruit quality assessment Fruit fresh weight was measured and dry weights recorded to calculate % water loss from each treatment unit of six fruit.

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Results

The combined results of water loss (%) from the stems of different cherry varieties (Stella, Sweet Georgia and Sweetheart) at the different treatment temperatures (5oC or 20oC) at the different flow rates (0, 25, 50 and 100 mL air per minute) are presented in Figure 106. The results show that the storage environment has a large impact on water loss from the cherry stems. Water loss from the stem is dependent on the storage temperature, relative humidity and flow rate around the stems, where conditions with a low VP (5oC and 100% RH = 872 Pa) contributed to smaller losses in water from the stems than conditions with high VP (20oC and 70%RH = 1,871Pa).

0 20 40 60 80 100 5:70:Stella 5:70:Sweet Georgia 5:70:Sweetheart

80 60 40 20 0 5:100:Stella 5:100:Sweet Georgia 5:100:Sweetheart

80 60 40 20 0 20:70:Stella 20:70:Sweet Georgia 20:70:Sweetheart 80

Water Loss % Loss Water 60 40 20 0 20:100:Stella 20:100:Sweet Georgia 20:100:Sweetheart

80 60 40 20 0

0 20 40 60 80 100 0 20 40 60 80 100 Flow Rate

Figure 106. Relative water loss from stems of Stella, Sweet Georgia, or Sweetheart cherries after two days at 5oC or 20oC in 70% or 100% relative humidity under flow rates of 0, 25, 50 and 100 mL air per minute. The mean of the four replicates is presented as red closed symbols, whilst the individual replicates are represented with open symbols.

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The results showed that within each temperature and relative humidity combination, increasing the flow rates of the surrounding air increased the levels of water loss from the stems and fruit. However to simplify the overall effects, Figure 107 presents the combined data from the different cherry varieties. Across all varieties, there was a significant interaction between temperature, relative humidity and flow rate.

0 20 40 60 80 100 5:70 5:100

20:70 20:100

Water Loss % Loss Water 80

0 20 40 60 80 100 Flow Rate

Figure 107. Relative water loss from all cherry stems after two days at 5oC or 20oC in 70% or 100% relative humidity under flow rates of 0, 25, 50 and 100 mL air per minute. The mean of the four replicates is presented as red closed symbols, whilst the individual replicates are represented with open symbols.

It is important to note that the 0 mL air per minute treatment was conducted in a static system which was an inherently different system than the other flow rate treatments (Figure 103 and Figure 104). Therefore the direct comparison of the 0 mL / min results with the rest of the data should be viewed with caution. Therefore in this discussion, of the different flow rates (25, 50 and 100 mL / min) treatment results are presented separately. This is summarised in Table 24 with the 0 mL / min data omitted.

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Table 24. Effect of storage temperature (5oC or 20oC) and relative humidity (70% or 100%) and flow rates (25, 50 and 100 mL air per minute) on relative % water loss from cherry stems after two days of treatment. The least significant difference (5% level) was 6% water loss.

Temperature Flow rate Relative humidity (%) (oC) (mL / min) 70 % 100 %

25 24 9

5 oC 50 36 13

100 51 18

25 57 20

20 oC 50 78 30

100 86 41

There were significant variety and flow rate interactions, which mean that the different flow rates resulted in different water losses from the stems at the different temperature and relative humidity treatments. However, the overall effects of storage temperature and relative humidity on stem water loss are presented in Table 25.

Table 25. Effect of storage temperature (5oC or 20oC) and relative humidity (70% or 100%) on % water loss from cherry stems after two days of treatment. The least significant difference (5% level) was 7% water loss.

Temperature Relative humidity (%)

(oC) 70 % 100 %

5 oC 37 13

20 oC 74 30

As expected from the vapour pressure treatments (Table 23), the results clearly show that the higher storage temperature (20oC) and lower relative humidity (70% RH) resulted in greater water loss from the cherry stems.

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Stem condition

Stem freshness The combined results of the different treatments on the stem freshness scores in the different cherry varieties are presented in Figure 108. The results show that in general, increasing flow rates around the cherry stems resulted in higher or worse ‘freshness’ scores of the stems, ie less appealing stems. There was a significant interaction between storage temperature, relative humidity and flow rate on stem freshness after two days treatment for the combined cherry data. The data is summarised in Table 26.

Table 26. Effect of storage temperature (5oC or 20oC) and relative humidity (70% or 100%) and flow rates (0, 25, 50 and 100 mL air per minute) on stem freshness score after two days of treatment. The least significant difference between the treatments (5% level) is 0.56. (Stem freshness score: 1 – stem full and plump, 2 – some notable water loss, 3 – unacceptable, significant water loss and 4 – fully dry).

Stem Freshness Score

Relative humidity (%) Temperature Flow rate

(oC) (mL / min) 70 % 100 %

0 2.47 1.97

5 oC 25 2.12 2.01

50 2.15 2.05

100 2.43 2.08

0 3.24 1.93

20 oC 25 2.83 2.36

50 3.30 2.28

100 3.58 2.46

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0 20 40 60 80 100 5:70:Stella 5:70:Sweet Georgia 5:70:Sweetheart 4.0 3.5 3.0 2.5 2.0 5:100:Stella 5:100:Sweet Georgia 5:100:Sweetheart 4.0 3.5 3.0 2.5 2.0

20:70:Stella 20:70:Sweet Georgia 20:70:Sweetheart 4.0 3.5 3.0 2.5

Post treatment freshness score freshness treatment Post 2.0 20:100:Stella 20:100:Sweet Georgia 20:100:Sweetheart 4.0 3.5 3.0 2.5 2.0

0 20 40 60 80 100 0 20 40 60 80 100 Flow Rate

Figure 108. Stem freshness scores stems of Stella, Sweet Georgia, or Sweetheart cherries after two days at 5oC or 20oC in 70% or 100% relative humidity under flow rates of 0, 25, 50 and 100 mL air per minute. (Stem freshness score: 1 – stem full and plump, 2 – some notable water loss, 3 – unacceptable, significant water loss and 4 – fully dry). The mean of the four replicates is presented as red closed symbols, whilst the individual replicates are represented with open symbols.

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Although there were significant variety and flow rate interactions, the main effects of storage temperature and relative humidity on stem freshness is presented in Table 27.

Table 27. Effect of storage temperature (5oC or 20oC) and relative humidity (70% or 100%) on stem freshness scores of cherry stems after two days of treatment. The least significant difference (5% level) is 0.67.

Temperature Relative humidity (%)

(oC) 70 % 100 %

5 oC 2.29 2.03

20 oC 3.24 2.26

As expected from the vapour pressure treatments (Table 23), the results clearly show that the lower storage temperature (5oC) and higher relative humidity (100% RH) resulted in lower stem freshness scores, ie fresher looking stems.

Stem browning The combined results of the different treatments on the stem browning scores in the different cherry varieties are presented in Figure 109. The results show that in general, increasing flow rates around the cherry stems resulted in increased stem browning scores.

There were no interactions between any of the treatments and none of the treatments affected stem browning except the relative humidity of the storage environment, where the stems stored at the high RH (100% RH) were slightly (but statistically) more green than those stored at the lower RH (70%) (Table 28).

Table 28. Effect of overall relative humidity on cherry stem browning score. (Stem browning score; 1 – bright green, 2- <10% brown, 3 – 10-25% brown and 4 - >25% brown stem). The least significant difference (5% level) is 0.07.

Relative humidity (%)

70% 100%

3.23 3.13

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0 20 40 60 80 100 5:70:Stella 5:70:Sweet Georgia 5:70:Sweetheart 4.0

3.5 3.0

2.5

2.0 5:100:Stella 5:100:Sweet Georgia 5:100:Sweetheart 4.0

3.5

3.0 2.5

2.0 20:70:Stella 20:70:Sweet Georgia 20:70:Sweetheart 4.0 3.5

3.0 2.5

Post treatment stem browning score stem treatment Post 2.0 20:100:Stella 20:100:Sweet Georgia 20:100:Sweetheart 4.0 3.5

3.0 2.5

2.0

0 20 40 60 80 100 0 20 40 60 80 100 Flow Rate

Figure 109. Browning of the stems of Stella, Sweet Georgia, or Sweetheart cherries after two days at 5oC or 20oC in 70% or 100% relative humidity under flow rates of 0, 25, 50 and 100 mL air per minute. (Stem browning score; 1 – bright green, 2- <10% brown, 3 – 10-25% brown and 4 - >25% brown stem) The mean of the four replicates is presented as red closed symbols, whilst the individual replicates are represented with open symbols.

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Relationship between water loss and stem diameter

Interestingly, there was a significant relationship between water loss and the stem diameter. This is illustrated with all the different treatment combinations in Figure 110. The combined and summarised results for the different varieties are presented in Figure 111. This shows that stem diameter is a direct function of water loss from the cherry stem and maybe a useful indicative factor of stem quality.

0.6 0.8 1.0 1.2 0.6 0.8 1.0 1.2 Stella:70:5 Stella:70:20 Stella:100:5 Stella:100:20

Sweet Georgia:70:5Sweet Georgia:70:20Sweet Georgia:100:5Sweet Georgia:100:20

20 Water Loss % Loss Water 0

Sweetheart:70:5 Sweetheart:70:20 Sweetheart:100:5 Sweetheart:100:20

0.6 0.8 1.0 1.2 0.6 0.8 1.0 1.2 Stem diameter (mm)

Figure 110. Water loss of the stems of Stella, Sweet Georgia, or Sweetheart cherries after two days in 70% or 100% relative humidity at 5oC or 20oC, as related to the stem diameter (mm) after treatment.

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100 80 60 40 20 Water Loss % Loss Water

0.6 0.8 1.0 1.2 Stem diameter (mm) Sweet Georgia

100 80 60 40 20 Water Loss % Loss Water

0.6 0.8 1.0 1.2 Stem diameter (mm) Sweetheart

100 80 60 40 20 Water Loss % Loss Water

0.6 0.8 1.0 1.2 Stem diameter (mm) Stella

Figure 111. The raw data and fitted linear regression with 95% confidence bands describing the relationship between water loss % of the stems of Sweet Georgia (top), Sweetheart (middle) and Stella (bottom) cherries and stem diameter (mm) after treatment. The relationship between stem diameter and water loss for each variety is described by the regressions, where y = % water loss and x is the stem diameter (mm); Sweetheart y = 184.96±9.30 – 147.35±8.64 x x This relationship accounted for 85.3% of the variance. Sweet Georgia y = 240.63±9.62 – 211.85±9.84 x x This relationship accounted for 88% of the variance. Stella y = 216.88±8.17 – 219.8±10.2 x x This relationship accounted for 88% of the variance. This relationship means for example that in these experiments with Stella cherry stems, every 0.1mm of decrease in stem diameter was a result of 21.9% level of relative water loss from the cherry stem.

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2. Fruit with stems attached These experiments were carried out on two varieties of cherries, Sweetheart and Sweet Georgia. The data were analysed according to variety and storage temperature and the results compared. The 70%RH static (0 mL/min) storage conditions proved to be exceptionally dehydrating and therefore were not valid static controls. For this reason the results from these samples were not included in the analysis. The static 100% RH controls generally remained unchanged by the storage conditions and in some cases gained weight which reflected the level of dehydration of the cherries at zero time. As generally the data are compared to the zero time values, the 100%RH static control values are not included in the analysis.

Water loss For both cherry varieties, water loss from the cherries (fruit +stem) occurred with all treatments with air flow rates of 25, 50 and 100ml/min (Figure 112). As observed in the previous section, water loss increased with increasing air flow rate, with higher temperature and lower relative humidity. For both cherry varieties, the most dehydrating storage conditions were at 20°C 70%RH a nd least dehydrating at 5°C 100%RH, with an airflow rate of 100mL/min being most and 25 mL/min least dehydrating. Similar levels of water loss were seen for both varieties for 5°C 100%RH, 20°C 100%RH and 5°C 70%RH. Very low amounts of water were lost from the cherry fruit at 5°C 100%RH with water loss not increasing much with increasing air flow rate; so 5°C 100%RH is the ideal storage c onditions to minimise water loss. In contrast, storage at 20°C 70%RH caused significa ntly higher levels of dehydration with the Sweetheart cherries becoming more dehydrated than the Sweet Georgia cherries under the same conditions. Hence storage at 20°C with low humidity should be avoided.

Stem weight and stem water content There were no differences in the fruit (stem detached) weight for either variety after the treatment. However, there were significant effects of both relative humidity and air flow rate on stem weight for treatments at 20°C for both cherry varieties, but not at 5°C (except for flow rate for Sweet Georgia cher ries) (Figure 113).

The same pattern is also reflected in the stem water content (Figure 114) where the dehydrating effect of storage at 20°C 70%RH was app arent.

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Percentage water loss - Sweetheart cherries

5.0

4.5

4.0

3.5

3.0 20C 70%RH 5C 70%RH 2.5 20C 100%RH

2.0 5C 100%RH

Percentage water loss water Percentage 1.5

1.0

0.5

0.0 0 25 50 75 100 125 Air Flow rate (mL/min)

Percentage water loss - Sweet Georgia cherries

5.0

4.5

4.0

3.5

3.0 20C 70%RH 5C 70%RH 2.5 20C 100%RH 2.0 5C 100%RH

Percentage water loss water Percentage 1.5

1.0

0.5

0.0 0 25 50 75 100 125 Air Flow rate (mL/min)

Figure 112. Percentage water loss from Sweetheart (top) and Sweet Georgia (bottom) cherries after two days at 5°C or 20°C in 70% or 100% relative humidity under air flow rates of 25, 50 or 100 mL/min. Values represent the mean of four replicates of six cherries (fruit with stems attached).

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Posttreatment stem weight - Sweetheart

0.60

0.50

0.40

5C 100%RH 20C 100%RH 0.30 5C 70%RH 20C 70%RH

0.20 Posttreatment(g) stem weight

0.10

0.00 0 25 50 75 100 125 Air Flow Rate (mL/min)

Posttreatment stem weight - Sweet Georgia

0.60

0.50

0.40

5C 100%RH 20C 100%RH 0.30 5C 70%RH 20C 70%RH

0.20 Posttreatment(g) stem weight

0.10

0.00 0 25 50 75 100 125 Air Flow Rate (mL/min)

Figure 113. Stem weight for Sweetheart (top) and Sweet Georgia (bottom) cherries after two days at 5°C or 20°C in 70% or 100% relati ve humidity under air flow rates of 25, 50 or 100 mL/min. Values are the mean of four replicates of six stems.

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Stem water content posttreatment - Sweetheart

0.40

0.35

0.30

0.25 5C 100%RH 20C 100%RH 0.20 5C 70%RH 20C 70%RH

Water(g) content 0.15

0.10

0.05

0.00 0 25 50 75 100 125 Air Flow Rate (mL/min)

Stem water content posttreatment - Sweet Georgia

0.40

0.35

0.30

0.25 5C 100%RH 20C 100%RH 0.20 5C 70%RH 20C 70%RH

Water content (g) Water content 0.15

0.10

0.05

0.00 0 25 50 75 100 125 Air Flow Rate (mL/min)

Figure 114. Stem water content for Sweetheart (top) and Sweet Georgia (bottom) cherries after two days at 5°C or 20°C in 70% or 10 0% relative humidity under air flow rates of 25, 50 or 100 mL/min. Values are the mean of four replicates of six stems.

Stem weight and stem diameter It was previously shown that there was a good relationship between stem diameter and stem water content, which is reflected in the stem weight. The results in this experiment with Sweetheart cherries also show this relationship (Figure 115). For Sweetheart cherries, the relative humidity level and the air flow rate significantly influenced stem diameters after storage at 20°C but not 5°C (data not shown), suggesting the lower storage temperature (and lower VP) result in less dehydrating conditions to the stem.

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Post Treatment stem weight Vs stem diameter Sweetheart cherries

0.65 y = 0.8715x - 0.2885 R2 = 0.8705 0.60

0.55

0.50

0.45

0.40 Post TRTstem weight (g)

0.35

0.30 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Stem diameter (mm)

Figure 115. Correlation of stem weight (g) with stem diameter (mm) after treatment. The linear regression equation is y = 0.8715x – 0.2885, where x = stem diameter (mm) and y = stem weight (g); r2 = 0.8705 (p <0.0001).

Stem freshness For Sweetheart cherries, increasing flow rates resulted in significantly less fresh looking stems at 20°C. As shown in Figure 116, the 20°C 70%RH storage conditions resulted in significantly higher freshness score at the high flow rate (100mL/min) indicating highly dehydrating conditions.

Change in Stem freshness score with treatment - Sweetheart cherries

1.2

1.0

0.8

20C 70%RH 20C 100%RH 0.6 5C 70%RH 5C 100%RH

Change in stem freshness in Change 0.4

0.2

0.0 0 25 50 75 100 Airflow rate (mL/min)

Figure 116. The change in stem freshness score for sweetheart cherries after two days stored at 5°C or 20°C in 70% or 100% relative humidity under air flow rates of 25, 50 or 100 mL/min. Values represent the mean of four replicates of six stems. (Stem freshness score: 1 – stem full and plump, 2 – some notable water loss, 3 – unacceptable, significant water loss and 4 – fully dry).

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For Sweet Georgia cherries, the freshness score was significantly influenced by the %RH and flow rate with storage at 20°C and by the % RH at 5°C. As shown in Figure 117, storage at 70%RH at either temperature resulted in higher stem freshness score (ie less ‘fresh’) of Sweet Georgia cherries than at 100%RH. The Sweet Georgia cherry stems had a greater change in stem freshness score than the Sweetheart cherry stems.

Stem Freshness Score pre- and post-treatment - Sweet Georgia

4.0

3.5

3.0 20C 70%RH post-TRT 20C 100%RH post-TRT 5C 70%RH post-TRT 5C 100%RH post-TRT 2.5 Pretreatment Stem Freshness StemScore Freshness

2.0

1.5 0 25 50 75 100 Airflow rate (mL/min) Figure 117. The stem freshness score of Sweet Georgia cherries before and after two days stored at 5°C or 20°C in 70% or 100% relat ive humidity under air flow rates of 25, 50 or 100 mL/min. Values represent the mean of four replicates of six stems. (Stem freshness score: 1 – stem full and plump, 2 – some notable water loss, 3 – unacceptable, significant water loss and 4 – fully dry).

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General discussion The results showed that the storage environment of cherry fruit is strongly influenced by the temperature, relative humidity and flow rate of the surrounding air in which the cherries are displayed. Water loss from the stems was strongly affected by all three storage factors. As expected, according to the vapour pressures of the different treatments, the order of the greatest water loss from the stems is presented in Table 29. This was derived from the data in Table 24 and clearly shows that water loss from the stems was greatest in the high temperature (20oC) and low humidity storage (70%). These display conditions were similar to those observed at ambient open display conditions in the retail environment as described in the previous section. The treatments with the lowest water loss from the stems were the low temperature storage (5oC) with high relative humidity (100%). These conditions are similar to the refrigerated displays in the retail environment as described in the previous section.

Table 29. Ranking of temperature, relative humidity (RH), flow rate (mL air / min) treatments on the average water loss from the stems of three cherry varieties. The least significant difference is 5.89%. Different letters indicate statistical differences (P<0.05).

Rank Temp RH Flow rate Water loss (oC) (%) (mL/min) (%) Most dry stems 1 20 70 100 a (86) 2 20 70 50 b (78) 3 20 70 25 c (57) 4 5 70 100 c (51) 5 20 100 100 d (41) 6 5 70 50 de (36) 7 20 100 50 ef (30) 8 5 70 25 fg (24) 9 20 100 25 gh (20) 10 5 100 100 hi (18) 11 5 100 50 ij (13) Most moisture 12 5 100 25 j (9) retained by stems

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Stem browning was only affected by the relative humidity of the storage environment, where high relative humidity (100% RH) had green stems. However the overall ‘freshness’ of the stems was significantly affected by all three storage factors and is a better indication of stem acceptability. Table 30 is a summary of the data presented in Table 26.

Table 30. Ranking of temperature, relative humidity (RH), flow rate (mL air / min) treatments on the average stem freshness scores of three cherry varieties. The least significant difference is 0.56. Different letters indicate statistical differences (P<0.05). (Stem freshness score: 1 – stem full and plump, 2 – some notable water loss, 3 – unacceptable, significant water loss and 4 – fully dry). Rank Temp RH Flow rate Stem freshness (oC) (%) (mL/min) Score Most ‘dry’ stems 1 20 70 100 a (3.58) 2 20 70 50 ab (3.30) 3 20 70 25 bc (2.83) 4 20 100 100 cd (2.46) 5 5 70 100 cd (2.43) 6 20 100 25 cd (2.36) 7 20 100 50 d (2.28) 8 5 70 50 d (2.15) 9 5 70 25 d (2.12) 10 5 100 100 d (2.08) 11 5 100 50 d (2.05) Most ‘fresh’ stems 12 5 100 25 d (2.01)

These results are in general agreement with the water loss rankings and show that high temperature (20oC) and low humidity (70%) storage resulted in significantly less fresh stems than the other treatment combinations.

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The experiments using cherries with attached stems reinforce the results of the experiment done with detached cherry stems. It shows that retail display conditions of low humidity and ambient temperature (20°C) are dehydrating for cherries and will result in dehydration of the cherry and deterioration of the stems especially if exposed to high air flow conditions. Also storage at 5°C at low humidities and high airflow conditions will also result in deterioration of the fruit and stems. Storage at 5°C at high humidity under static conditions provid es the optimal conditions for preservation of cherry fruit and stem condition.

In conclusion, the results clearly demonstrate the importance of temperature and relative humidity during the retail display of cherries. Low temperature and high relative humidity during display are the best conditions to maintain stem quality. It is also important to recognise the importance of reducing air flow around the cherry stems during display.

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4.3 Preliminary evaluation of different cherry packaging types

Background The most common method of displaying and selling cherry fruit is in an open display, where the packed box of fruit is opened and displayed for the consumer to select their fruit. This display type has been common for many years and allows the consumer to select what fruit they will purchase. This display can either be at store (ambient) temperatures, or in a refrigerated wall cabinet. The advantages of this display is that if the display is full and with good quality fruit, then the display is very attractive and can be put in a prominent part of the store to attract sales. Apart from its deleterious effects on fruit and stem quality, this type of display which is open to the public whereby consumers can paw through the open display handling and damaging the fruit. This can also lead to food safety issues where unregulated people are handling food (cherry fruit) with their bare hands. Packaging is a simple was of protecting cherry fruit during transport, handling and retail. A number of packaging alternatives have been trialled and used in Australia and overseas.

Punnets or clam shells The use of pre-pack punnets is common in the USA. The clear plastic punnet provides protection of the fruit from bruising, allows easy handling at the retail environment, unit pricing and allows scan and marketing information to be displayed on the punnet. This also does not allow consumers to physically touch the fruit, thereby avoiding any potential food safety issues. The disadvantages of this system, is that the punnets are pre-weighed which creates problems if an individual cherry fruit is rotten within the punnet as it cannot be simply discarded without affecting the pre-pack weight.

Individual plastic bags The use of pre-weighed individual bags allows consumers to select a whole bag of fruit from the display, rather than selecting individual fruit. This encourages a standardised bag weight (sale) and discourages consumers from sifting through the fruit to select fruit they want. In addition, if there are any rotten fruit in the bag, they can easily be removed.

Aim The aim of this trial was to investigate the effects of different packaging types on cherry fruit quality before and after a three week storage period. Note that this is a single preliminary storage trail with one variety (Sweet Georgia) from one batch / harvest.

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Methods

Sweet Georgia cherry fruit were re-packaged into three different packaging types (Figure 118): a. open individual bags (similar to grape bags) b. 500g punnets (500g clear punnets) and, c. standard display (open) The fruit were packaged into 500g treatment units. Each treatment unit was replicated four times and kept together to simulate commercial display. Half the fruit were held at 6oC (simulating refrigerated display) and 20oC (simulating non- refrigerated display) for three days before fruit quality assessment. The other half of the fruit were stored in plastic over-wrapped polyethylene bags for three weeks at 0oC then a further three days at retail display temperatures (6oC and 20oC). Temperature and relative humidity in each packaging type were recorded with data loggers. This trial commenced on 24 January 2012.

Figure 118. Plastic bags (top left), clear plastic punnets (top right), the open display (bottom left) and a comparison of the treatments (bottom right) used in the storage trials

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Part 1. Evaluation of packing types with no storage Prepare package types and leave at 6 oC or 20oC for 3 days then assess fruit quality and weight loss. Part 2 – Evaluation of packing types after storage Store the packed cherries in over-wraps plastic (for bags), or in LifeSpan bags for open display. After 3 weeks storage at 0oC leave at retail simulation (Part 1) for evaluation after a further 3 days.

Evaluation methods Fruit and stem quality was measured at the beginning of the trial and after each removal (and shelf life) assessment. Stem browning was assessed on 50 representative fruit per replicate. Combined fruit weights were measured before and after storage. In addition the weight of rots in each treatment was weighed and compared. The quality of the Sweet Georgia fruit at the beginning of the experiment was reasonable and were representative of the quality in the market (Section 2). Stem quality was good (97% of all stems were acceptable, with an average stem score of 2.3) and fruit firmness was 306 g/mm2 (FirmTech). The effect of packaging treatment on the proportion of cherries with acceptable stems (stem scores 1, 2 or 3) was tested using a generalised linear model in GenStat with binomial error distribution and logit link function. Preliminary analysis using GLMM found the replicate effect to be negligible. Fruit firmness, water loss %, postharvest rots % were analysed using ANOVA.

Results

There was no effect of packaging on water loss from the cherries when the fruit was stored at 6oC. However when the fruit was stored at 20oC, the stems in the open displays lost significantly more water (2.7% water loss) than fruit in the bags (1.4%) or in the punnets (1.0%). The results also showed that were no differences in stem condition between the different packaging treatments when the fruit was stored at 6oC. However when the fruit was stored at 20oC, the stems of the fruit in the open displays were always browner compared to the stems on the fruit in the bags or in the punnets (Table 31, Figure 119).

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Table 31. Effect of packaging type on the % acceptability of stem condition in fruit stored at 20oC for three days. Different letters within the same row are statistically different (P>0.05)

Bag Open display Punnet No storage 95b 86a 98b After 3 weeks storage 92b 82a 89ab

Figure 119. The effect of packaging type (bags – left, open display – middle, punnets – right) on stem browning of Sweet Georgia cherries stored at 20oC for three days.

The type of packaging did not affect fruit firmness during storage or the display temperature (data not shown).

The levels of rots were not affected by package type, except for fruit in the 20oC display simulation. In this case, the level of rots was significantly higher (32% rots) in the punnets than in the bag (21% rots) and in the open display (14% rots). Figure 120 shows the nesting of postharvest rots in the punnets after three days storage at 20oC.

Figure 120. Nesting of storage rots in punnets of Sweet Georgia cherry fruit.

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Discussion

Packaging is a simple and very efficient way to reduce fruit transpiration and water loss. In this experiment, packaging had no effect on the water loss when the fruit was stored at 6oC, but when the fruit was stored at 20oC, the fruit in the open display lost more water than the different packaging types. This was reflected in the level of stem browning on fruit in the open displays which were always less acceptable, compared to the stems on the fruit in the bags or in the punnets at 20oC. Although the higher level of rots in the punnets at 20oC is a concern, adequate pre- and postharvest decay control should control or minimise postharvest rots. These preliminary results show that the punnets and bags were equally effective in reducing water loss and maintaining stem condition during storage at 20oC. However more work is required to quantify these observations and evaluate the different packaging types with a wider range of varieties from different grower lines and growing areas where differences in initial quality may affect the performance of the packaging.

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4.4 Use of coatings to maintain cherry fruit and stem quality

The appearance of fresh cherries is a critical quality assessment to consumers. A shiny appearance and a green stem, free from brown discolouration are desirable. However cherry fruit deteriorate rapidly after harvest and in some cases do not reach consumers at optimal quality after transport and marketing. Stem browning as a result of water loss is thought to be a major contributor to loss of perceived quality after storage and retail. There is an increasing interest in the use of edible coating to maintain fruit quality. Such edible coatings act as physical barriers on fruit surface and decrease its permeability to O2, CO2 and water vapour, leading to reductions in respiration rate and transpiration and to a retard in the natural physiological ripening process. Some potential benefits of edible coatings include: • reduced moisture loss, • improved appearance, • production of a modified atmosphere in the fruit, • carriers of fungicides and antioxidants, • reduced aroma loss, • reduced decay or deterioration and • reduced food packaging waste stream

Edible coatings and waxes have been used for many years on various horticultural produce, such as apples to improve food appearance and maintain fruit quality. Waxes have been used on fruits and vegetables since the 1920s. They are all made from natural ingredients, and are certified by Food and Drug Administrations around the world to be safe to eat. Different compounds have mainly been used as edible coatings to prevent fruit and vegetable water loss, including wax, milk proteins, celluloses, lipids, starch, zein, and alginate. Carnauba wax (eg Apple GlazeTM) is most commonly used coating in Australia and is derived from the leaves of a palm tree.

Other commercial waxes and coatings include:

• Poly ShineTM is a commercial polyethylene coating for citrus fruit which has been used for many years. Poly ShineTM is good for maintaining freshness, moisture control and eating qualities of citrus.

• SemperfreshTM fruit coating is composed of sucrose esters of fatty acids, sodium carboxymethylcellulose and mono and diglycerides of fatty acids.

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Effects of coatings on cherry fruit quality

Some beneficial effects of maintaining cherry fruit quality have been obtained with some edible coatings based on chitosan (Romanazzi et al., 2003), Aloe vera gel (Martínez-Romero et al., 2006), alginate (Diaz-Mula et al. 2011) and SemperfreshTM (Yaman and Bayindirh, 2001; 2002). However, these authors showed an increase in fungal spoilage in SemperfreshTM coated cherries. In addition, sweet cherries coated with Food Coat®, an edible coating composed of derivatives of fatty acids and polysaccharides in alcohol solution (Domca, Spain) were shiner, more turgid and more attractive than controls after storage, although no significant effects were observed on the parameters that related to fruit quality such as colour and firmness (Alonso and Alique, 2004). The aims of these series of experiments were to assess commercial waxes / coatings and to identify and evaluate potential edible coatings/films for the maintenance of cherry fruit and stem quality.

This was conducted in two parts: 1. Evaluation of existing commercial coatings / waxes

2. Development and assessment of new edible coatings to maintain fruit and stem quality

Evaluation of existing coatings / waxes

Evaluation of Poly ShineTM coating on cherry fruit and stem quality

Lapin cherry fruit and stems were treated with Poly ShineTM (1:1 water). All cherries were briefly rinsed in water before treatment to remove any contaminates. Coating with Poly ShineTM was achieved by dipping the fruit +stem, stem only or fruit only, as appropriate, into the Poly ShineTM solution for 10 seconds, then allowing excess to drain off, then allowing the coating to dry 30 minutes, before subjecting the fruit to different storage treatments at 20oC. These fruit were compared to no coating treatments (just dipped in water). These treatments were stored at 20oC, 65% relative humidity (VP 1,797 Pa) and with an airflow rate of 50 mL/min. To compare this storage environment, controls with treated and no-coating control cherries were stored under static conditions (0 mL/min) at 20 C, 100% RH (VP 2,337 Pa).

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Treatment summary

Treatment 1 Poly ShineTM coating of fruit and stem, 65%RH, 50 mL/min Treatment 2 Poly ShineTM coating of fruit only, 65%RH, 50 mL/min Treatment 3 Poly ShineTM coating of stem only, 65%RH, 50 mL/min Treatment 4 No coating; Fruit and stem immersed in water only, 65%RH, 50 mL/min Treatment 5 Poly ShineTM coating of fruit and stem, 100%RH, 0 mL/min Treatment 6 Poly ShineTM coating of fruit only, 100%RH, 0 mL/min Treatment 7 Poly ShineTM coating of stem only, 100%RH, 0 mL/min Treatment 8 No coating; Fruit and stem immersed in water only, 100%RH, 0 mL/min

Two airflow boards were adjusted to an airflow rate of 50 mL/min. Treatment replicates were randomly allocated bottles and the connections from board outlets to bottles were also randomly allocated. For each treatment 1-4 there were four replicates, each with 5 cherries (fruit with stem attached). For each treatment 5-8 there were two replicates, each with 5 cherries (fruit with stem attached). Treatments 1-4 were stored in 2L respiration jars, whilst treatments 5-8 were stored in individual sealed 4L plastic containers approximately one third filled with water. The treatment time was 42 hours.

Before and after treatment, stem browning was subjectively scored (as standard scoring system – Section 2), and water loss determined.

Results Stem browning Stem condition was maintained in the fruit and stems stored in the 100%RH, 0 mL/min treatments (Figure 121). VPDs were low in this storage treatment, which did not dehydrate or stress the stems. Although there was no significant difference between the 65%RH 50mL/min storage conditions, the Poly ShineTM treatments of ‘fruit+stems’ and ‘stems only’ slowed the rate of stem browning as compared to the ‘PS fruit only’ and ‘water only’ treated cherries. Thus the Poly ShineTM treatment retarded the deterioration of stem condition when the fruit and stems are coated or just the stems coated in the 65%RH 50mL/min storage conditions.

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Stem browning scores- Polyshine treatment

4.00

3.50

3.00

2.50 65%RH 50mL/min Zero time 65%RH 50mL/min Final 2.00 100%RH 0 mL/min Zero time 100%RH 0 mL/min Final 1.50 Stem Brown score

1.00 0.50 0.00 PS fruit & stem PS fruit only PS stem only DW only Treatment Figure 121. Stem browning scores on stems treated with on the stem only, fruit + stem and fruit only. The control fruit were dipped in water only.

To further investigate the effects of Poly ShineTM, the results of the Poly ShineTM treatments were analysed separately across all the storage treatments and showed that the application of the Poly ShineTM treatment to the fruit and stem resulted in a significantly reduced stem browning across the average of the treatment (Table 32). However the application of the Poly ShineTM treatment to the fruit or the stem only resulted in the same level of browning as the water control.

Table 32. Average stem browning score after 66 hours storage at 20oC. Values not sharing the same letter are significantly different from each other (p<0.05). Treatment Average stem score Poly ShineTM fruit and stem 2.75 a Poly ShineTM stem only 3.10 ab Water control (fruit and stem) 3.45 b Poly ShineTM fruit only 3.50 b

Water loss Figure 122 shows the water loss after storage of the different treatments. There were no treatment differences between any of the 65%RH, 50mL/min treatments. The Poly ShineTM treatment of any form was no better than the control (water dip) in preventing weight loss by the fruit plus stem over the period of the treatment. The cherry fruit and stems did not lose any water under 100%RH storage conditions, irrespective of treatment and retained about 2% more water content than the 65% RH treatments. This reinforces the results Section 4.2, where the higher VPD in the 65% RH treatments resulted in more water loss.

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Mean post-treatment weight as % of pre-treatment weight - Polyshine treatment 100.50%

100.00% 99.50% 99.00% 65%RH 50mL/min 100%RH 0mL/min 98.50%

98.00% weight % pre-treatment of 97.50%

97.00% PS fruit & stem PS fruit only PS stem only DW only Treatment

Figure 122. Average water loss as a percentage of before treatment fresh weight in Lapin cherry fruit treated with Poly ShineTM and stored under different RH and flow rates.

Evaluation of Poly ShineTM and SemperfreshTM coatings on cherry fruit and stem quality This experiment examined the effectiveness of two commercial fruit coatings, Poly ShineTM and SemperfreshTM on maintaining fruit and stem quality. Sweetheart cherry fruit with stems attached were stored at 20oC and exposed to the open air on the bench, after being coated with Poly ShineTM or SemperfreshTM. The coating was applied to either the stem only, the fruit only or the fruit+stem. A control fruit were dipped in water.

Treatment Summary Treatment 1 Water dip of the fruit and stem – control Treatment 2 Poly ShineTM coating of the stems only Treatment 3 Poly ShineTM coating of the fruit only Treatment 4 Poly ShineTM coating of the fruit and stem Treatment 5 SemperfreshTM coating of the stems only Treatment 6 SemperfreshTM coating of the fruit only Treatment 7 SemperfreshTM coating of the fruit and stem

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There were four replicates of 8 fruit and stem for each treatment combination. The Poly ShineTM treatment was prepared with a 1:1 dilution by volume with water. The SemperfreshTM treatment dip contained 0.5% SemperfreshTM in water with 500 ppm iprodione (fungicide).

Before any treatment, all cherries were rinsed in water before use. According the treatment, the cherry fruit / stem was dipped into the appropriate coating solution for 10 seconds, the excess solution was drained off and the coated cherry then allowed to air dry (Figure 123). The treated fruit were stored at 20oC at 86%RH (VP 2,177 Pa) for 66 hours. The airflow was around the fruit was minimal (ambient air conditioning). Fruit and stem condition were subjectively scored, stem diameters measured (stem diameters 1 - middle of stem; stem diameter 2 - mid-way between middle of stem and cherry end of stem; and stem diameter 3 - mid-way between middle of stem and tree end of stem). Water loss was determined at the end of the 3 day treatment at 20oC.

Figure 123. Treatment of cherry fruit / stems with Poly ShineTM. The fruit and / or stem were dipped into the appropriate coating solution for 10 seconds before air drying.

Results Stem browning There was an increase in stem browning (as subjectively assessed using the Stem Score) with all treatments but with a large variability in values between replicates within each treatment (Figure 124). The results showed that there were no differences in stem browning except in the “SemperfreshTM stem only” treatment, which had an increase in stem browning. The Poly Shine™ coating of the stem only did result in a smaller change in stem browning than Poly Shine™ coating of the fruit only, Semperfresh™ coating of stems only and Semperfresh™ coating of fruit and stems.

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Change in Stem Score with Treatrment (Posttreatment score - Pretreatment score)

1.2 d

1.0

cd bc 0.8

ab abc abc 0.6

0.4 a Change instem score

0.2

0.0 Deionised PS stem PS fruit PS fruit & SF stem SF fruit SF Fruit & w ater only only stem only only Stem

Figure 124. Average (± Standard deviation) change (increase) in stem browning score with treatment with Poly Shine™, Semperfresh™ or deionised water (Control) after 66 hours storage at 20°C and 85%RH. Values wi th different letters are significantly different (p < 0.05); least significant difference of means = 0.3032. Water loss The average water loss (of the fruit with attached stem) ranged from 6.7% to 8.3% with treatments after 66 hours storage at 20°C and 85%RH (Figure 125). With the exception of the “Poly Shine™ fruit only” treatment which had a significantly lower water loss, no treatment had a significantly different level of water loss than the control (water only) treatment. The Semperfresh™ coating of fruit and stems treatment resulted in the highest water loss; though this was not significantly higher than the control treatment, it was significantly higher than for the Poly Shine™ coating of fruit only treatment.

Post-treatment % water loss - percentage of pre-treatment water content

10.0%

c 9.0% bc bc ab ab 8.0% ab a 7.0%

6.0%

5.0%

4.0%

Percentage water loss water Percentage 3.0%

2.0%

1.0%

0.0% Deionised PS stem only PS fruit only PS fruit & stem SF stem only SF fruit only SF Fruit & water Stem Figure 125. Average percentage (± Standard deviation) water loss on treatment with Poly Shine™, Semperfresh™ or deionised water (Control) after 66 hours storage at 20°C and 85%RH. Values with different letters are s ignificantly different (p < 0.05); least significant difference of means = 0.841.

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Stem diameters The results in the previous section showed that stem diameter is a good indicator of water status of cherry stems, in this experiment stem diameters were examined in relation to stem browning (colour) scores. Using treatment mean values, the results showed significant inverse relationships between stem browning score and the stem diameters measured at three positions on the stems (Figure 126). For example, the stem browning score correlated to a mid-stem diameter (stem diameter 1) with an r2= 0.65 (p=0.016). This indicates that the stem browning score is a reasonably good subjective measure of stem deterioration while stem diameter can be used as a quantitative measure.

Correlation between stem browning (colour) score and stem diameters (mean treatment values) Diameter 1 1.4 Diameter 2 Diameter 3 1.3 Linear (Diameter 1) Linear (Diameter 2) 1.2 Linear (Diameter 3)

1.1 Diameter 1 (mid) y = -0.3955x + 1.9851 1.0 R2 = 0.6506

0.9 Diameter 2

Stem diameter (mm) y = -0.4465x + 2.193 2 0.8 R = 0.7231

Diameter 3 0.7 y = -0.4375x + 2.1347 R2 = 0.6976 0.6 2.0 2.2 2.4 2.6 2.8 3.0 3.2 Stem browning (colour) score

Figure 126. Correlation between stem browning (colour) score and stem diameter. Values are treatment mean values. Diameter 1 is in the middle of the stem; Diameter 2 is mid-way between the middle and the cherry end of the stem; Diameter 3 is mid- way between the middle and the tree end of the stem.

Effects of storage on stem diameter For all treatments, stem diameters significantly decreased with storage, indicating water loss from the stem. The stem diameters from all treatments are presented in Figure 127. The Poly Shine™ coating of the stem only treatment resulted in significantly larger stem Diameters 2 and 3 (less shrivelling) than for the control (water treatment). While the other Poly Shine™ treatments were no better or worse than the control treatment, the Semperfresh™ treatments resulted in significantly smaller stem diameters (more shrivelling) than the control treatment.

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Effect of treatments on stem diameters

1.60

1.40

1.20

1.00

Diameter 1 0.80 Diameter 2 Diameter 3 Diameter (mm)Diameter 0.60

0.40

0.20

0.00 Deionised PS Stem PS fruit only PS fruit & SF stem SF fruit only SF Fruit & Zero time water only stem only Stem

Figure 127. Effect of Poly Shine™ and Semperfresh™ treatment after 66 hours storage at 20°C and 85%RH on stem diameters (Diamet er 1 – middle of stem; Diameter 2 – mid-way between middle and cherry end of stem; Diameter 3 – midway between middle and tree end of stem). Values are treatment means; error bars indicate +1 standard deviation.

Conclusions Although these experiments on the effects of Poly Shine™ and Semperfresh™ coatings on cherry fruit and stem quality were properly conducted and replicated within each experiment, the results need to be viewed with caution should verified with freshly sourced materials. There is some promise for the use of Poly ShineTM to slow the rate of water loss and stem browning, in fruit subject to retail conditions. In this experiment Semperfresh™ did not perform well, but this needs to be re-investigated with freshly sourced Semperfresh™.

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Development of new coatings to maintain cherry fruit and stem quality

Waxes and coatings are the most commonly employed materials used as edible films for whole fruit such as orange and lemon since the 12th century, mainly to reduce moisture loss (Olivas and Barbosa-Canovas, 2005). These have since been commercialised and widely used in other horticultural industries such as citrus and apples. However there are also many other potential film-forming biopolymers such as proteins and polysaccharides, which are useful in food application due to their ability to establish polymer interactions and create a continuous network responsible for the functional properties of films. Film-forming proteins such as gelatin (G), sodium caseinate (SC), soy protein isolates (SPI), whey protein isolates (WPI), and polysaccharides such as carboxymethyl cellulose (CMC), methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC) are commercially available and of low cost (Wang et al., 2007).

The selection of biopolymers to be used to form suitable films depends on a large number of factors, among them are the purpose of coating, type of produce, solvent characteristics of the film, as well as the film-forming and coating techniques employed. In the past 20 years, macromolecule-macromolecule interactions in biopolymer mixed system have been extensively studied, resulting in the advances of knowledge of key parameters involved. These advances enable the design of coatings or films with desired functional properties. However, the stability of the film or coating depends on the functional properties of individual biopolymers, and the nature and strength of protein-polysaccharide and polysaccharides-polysaccharides interactions in bulk solutions (Olivas and Barbosa-Canovas, 2005).

Additives such as preservatives, firming agents, colours, flavours and plasticisers can be added to the formulation to improve film properties. Some research suggested that additives applied as part of the films are more effective than when applied alone, as the additives can be maintained on the surface of the fruits by the coatings for a longer time (Olivas and Barbosa-Canovas, 2005). Plasticisers are used as additives in edible films to produce more flexible coatings by changing the tri-dimensional structure of polymeric materials and decreasing intermolecular forces along protein chains, thus creating film mobility. Immersion, spraying, or brushing followed by drying and cooling are the common ways of applying edible coatings on fruits. There are basic factors that need to be considered when formulating suitable coatings for fruits, among them are the two forces that are involved when coatings are applied onto the surface of fruits; adhesion between the coating and the fruit, and cohesion of molecules within the coating (Olivas and Barbosa-Canovas, 2005). The increase in cohesion would result in the increase of barriers properties and the decrease of flexibility of the film. On the other hand, the increase in adhesion increases the durability of the film on the surface of the fruit. Coatings become soggy when high water solubility coatings are applied onto high water activity fruits, giving an unpleasant appearance. Therefore, water solubility of an edible coating is also

154 among the basic factors that need to be taken into account. Some edible coatings might even act as nutrients for microbial growth in moist environment, therefore causing rapid spoilage. Thickness of the coating is also an important factor to consider. Increase in thickness might cause undesirable effects, such as the activation of anaerobic fermentation, which could lead to the quality loss of the fruit in terms of taste / flavour, colour and aroma. However, it is often difficult to produce uniform thickness among all batches of coated fruits.

Carboxymethyl cellulose Carboxymethyl cellulose (CMC) is widely used for a variety of applications in a number of industry, including food, pharmaceutical, and paper industries due to its most important characteristic property – high viscosity in low concentration (Yang and Zhu 2007). CMC also has other functional properties, such as thickening, defoaming abilities, surfactant, and bulking abilities (Baker, 1982; Yang and Zhu, 2007). It is non-toxic and non-allergenic (Baker, 1982), therefore is safe to be used in food applications including the coating of whole fruits such as cherries.

Gelatin Gelatin is categorized as a hydrocolloid, having the ability to act as an emulsifying agent, colloid stabilizer and gelling agent (Dickinson, 2008). Most hydrocolloids can act as stabilizers of oil-in-water emulsions, but only a few can act as emulsifiers and gelatin is one of the few (Dickinson, 2008). Gelatin is used as gelling or setting agent and is widely available commercially. Little is known on its ability and efficiency as edible coatings/films for produce such as fruits and vegetables. Due to its unique hydrophilic character, a great interest in the application of gelatin for maintaining the quality of high value perishable seasonal fruits such as cherries has been generated. Various edible films and coatings have been applied to cherry fruit; however no single coating formulation has provided a sufficiently effective treatment to maintain fruit quality during storage. As simple edible coatings provide an economical and relatively easy to adopt method, with potential applications immediately after harvest in the packing shed, the aim of this study was to characterise three types of edible films and evaluate their effects on moisture loss, TSS and TA of sweet cherries.

This work was conducted with the in the School of Environmental and Life Sciences at the University of Newcastle (Dr. Costas Stathopoulos, Senior Lecturer Food Science and Technology and Ron Lim – student) and with NSW Department of Primary Industries (Dr. John Golding).

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This work is the basis of an international peer-reviewed research paper: Lim, R., Stathopoulos, C. E. and Golding, J. B. (2011) Effect of edible coatings on some quality characteristics of sweet cherries. International Food Research Journal 18(4): 1237-1241.

Abstract Gelatine (G), carboxy-methylcellulose (CMC) and soy protein isolate (SPI) edible films were prepared at three different concentrations (1, 3 ,5%; 2, 3, 4%; and 3, 5 ,7% respectively) and heated at two different application temperatures (60 and 80C) before coating sweet cherry (Prunus avium L., cv. ‘Sweetheart’) fruit. Glycerol was used as a plasticiser, and each film was characterised for their resistance to water, acid and alkali. Standard fruit quality characteristics including changes in stem colour, moisture loss, fruit soluble solids content (SSC) and titratable acidity (TA) were monitored during storage at 2C. The SPI films were more resistant to water and alkali, while the most resistant to acid were gelatine films. CMC and SPI films showed increased resistance with increasing concentrations, while no concentration effect was observed for G films. Amongst the different films heated at 60C, the gelatine film ensured the lowest moisture loss during storage, while amongst films heated at 80C CMC was the most effective at reducing water loss. Fruit SSC for all coated cherries decreased during storage for two weeks, irrespective of the coating. The TA of the fruit coated with CMC and SPI decreased during cold storage and also with increasing concentration. However, there were no significant trends observed for gelatine coated samples. Results obtained in this study indicate that there is great potential to counteract moisture loss, the main parameter associated with quality loss in cherries by application of simple films after harvest.

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Other international cherry coatings research work Our collaborators at the Department of Food Technology at the University Miguel Hernandez in Alicante, Spain have published several new research papers examining new cherry coatings to maintain fruit quality and other fruit quality work (below). They showed that a novel edible coating based on Aloe vera gel was effective as a postharvest treatment to maintain sweet cherry quality and safety (Martinez-Romero et al., 2006). Dr Maria Huertas Diaz-Mula worked at Gosford Primary Industries Institute at NSW Department of Primary Industries during the 2010/11 cherry season. In her research work in Spain, they demonstrated the successful postharvest use of sodium alginate applied as edible coating on Sweetheart cherry fruit (Diaz Mula et al., 2011). These natural coatings which have or can incorporate natural anti-fungicidal action are a promising process to maintain and improve fruit quality.

Postharvest sweet cherry quality and safety maintenance by Aloe vera treatment: A new edible coating. Martinez-Romero, D. Alburquerque, N. Valverde, J. M. Guillen, F. Castillo, S. Valero, D. Serrano, M. Postharvest Biology and Technology. 2006. 39: 1, 93-100.

The use of alginate as edible coating alone or in combination with essential oils maintained postharvest quality of tomato. Zapata, P. J. Castillo, S. Valero, D. Guillen, F. Serrano, M. Diaz-Mula, H. M. Acta Horticulturae. 2010. 877, 1529-1534.

The use of natural antifungal compounds improves the beneficial effect of MAP in sweet cherry storage. Serrano, M. Martinez-Romero, D. Castillo, S. Guillen, F. Valero, D. Innovative Food Science & Emerging Technologies. 2005. 6: 1, 115-123.

Maturity stage at harvest determines the fruit quality and antioxidant potential after storage of sweet cherry cultivars. Serrano, M. Diaz-Mula, H. M. Javier Zapata, P. Castillo, S. Guillen, F. Martinez- Romero, D. Valverde, J. M. Valero, D. Journal of Agricultural and Food Chemistry. 2009. 57: 8, 3240- 3246.

Chemical constituents and antioxidant activity of sweet cherry at different ripening stages. Serrano, M. Guillen, F. Martinez-Romero, D. Castillo, S. Valero, D. Journal of Agricultural and Food Chemistry. 2005. 53: 7, 2741-2745.

Active packaging development to improve 'Starking' sweet cherry postharvest quality. Serrano, M. Martinez-Romero, D. Guillen, F. Castillo, S. Valverde, J. M. Valero, D. Acta Horticulturae. 2005. 682(Vol 3), 1675-1682.

Postharvest treatments with salicylic acid, acetylsalicylic acid or oxalic acid delayed ripening and enhanced bioactive compounds and antioxidant capacity in sweet cherry. Valero, D. Diaz-Mula, H. M. Zapata, P. J. Castillo, S. Guillen, F. Martinez-Romero, D. Serrano, M. Journal of Agricultural and Food Chemistry. 2011. 59: 10, 5483-5489.

Dr. Diaz-Mula at NSW Department of Primary Industries preparing cherry samples for treatment (January 2011)

Postharvest cherry research group. Department of Food Technology

University Miguel Hernandez in Alicante, Spain

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5. Technology transfer

Results of this project have been presented at:

• 2012 Victorian Cherry Conference - “Review the Season and Plan for the Future” Wangaratta Victoria (1 - 2 March 2012)

• National Cherry Technical Program at the 2011 National Cherry Conference in Adelaide (1 August 2011)

• NSW Cherry Growers Association in Orange (17 May 2011)

Summaries of this project have also been published in:

• ‘Tree Fruit’ Magazine

• Australian Cherry Industry Annual Industry Report (2010, 2011)

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‘Tree Fruit’ June-July 2011. page 9 ‘Improving quality and consistency of cherries to ensure market access’ John Golding and Michael Rettke

Improving the quality and consistency of Australian cherries 2010 Australian Cherry Industry Annual Report. page 5 John Golding

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Presented results of the project at the:

National Cherry Technical Program at the 2011 National Cherry Conference in Adelaide ‘From the shed door: Improving quality and consistency of Australian cherries’ John Golding and Michael Rettke Monday 1 August 2011

The results of this project were also presented at: 2012 Victorian Cherry Conference. “Review the Season and Plan for the Future” 1 - 2 March 2012. Wangaratta Victoria. “Update of retail survey 2010/11: Improving quality and consistency of Australian cherries”

Presented some preliminary results of the project to: NSW Cherry Growers Association Orange Agricultural Institute, NSW Department of Primary Industries 17 May 2011

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6. Recommendations

6.1 Specific recommendations to address the fruit quality issues identified in the project

Pitting and bruising were the major defects identified in the retail fruit quality survey in both survey years. Managing fruit pitting will become an increasing important aspect of storage and fruit quality for Australian cherry exports and strategies must be implemented to ensure pitting and bruising are not barriers to the growth of the Australian cherry industry.

Pitting A dual strategy is required to minimise fruit pitting. 1. Growing fruit that is less prone to pitting. Fruit variety is a major determinant of pitting and varieties should be selected that are less prone to pitting. 2. Minimising the level of physical damage to the fruit postharvest is required. Harvesting and postharvest handling and packing practices need to be continually monitored to ensure physical damage is minimised. Pitting can only be prevented if the source of the problem is identified. The results of a preliminary packing line survey in 2011/12 showed significant areas from the orchard and the packing line need attention to minimise pitting and fruit damage. All points along the harvest and packing line contribute to pitting and fruit damage. Cluster cutters appear to be a major source of damage leading to fruit pitting and require particular attention. For example the speed of the line needs to be optimised to minimise damage, whilst maintaining adequate throughput. The final stages of packing including the hand sorting and packaging were also identified as a source of fruit damage. This can be managed and minimised with improved education of sorters and packers. Although some large fruit drops onto hard surfaces in the packing line could be examined and improved. It is suggested that continual monitoring and follow up assessment of fruit pitting is integrated in QA practices. As well as good equipment design and product flow, equipment needs to be operated at its optimum speeds and throughput. A limitation of managing pitting is the lack of our understanding of its causes. Although impact damage in the handling and packing line do significantly contribute to pitting, we do not understand the limits of damage and their effects on pitting. More work, such as being conducted in Chile, needs to be investigated and extended to the Australian cherry industry.

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Bruising Varieties and orchard management practices that produce firm sound fruit will reduce the likelihood of fruit bruising occurring. However harvesting and postharvest handling and packing practices need to be continually monitored to ensure common practices such as fruit transfer, size grading and packing are not contributing to the bruising problem. Where bruising is a problem, it can only be prevented in future if the source of the problem is identified. In this preliminary survey of seven packingsheds, bruising was a major issue where damage could occur at any point in the harvest and handling chain, but key areas of concern are the cluster cutter and in the final stage of sorting and packing. It is suggested that monitoring and follow up assessment of fruit bruising is integrated in QA practises. As well as good equipment design and product flow, staff need to be appropriately trained in the careful handling of cherries, and the need to avoid damaging practices such as raking of the fruit to move it. Although the manual re-packing fruit is rarely necessary, it is absolutely essential that this process be done with extreme care. Retail The high level of bruising at retail needs to be addressed and more work is required to identify specific areas to improve. Practices that reduce the loss of firmness before sale, such as good temperature management and rapid stock rotation, are the most effective means of minimising bruising at retail level. But more work is needed at the retail level where strategies that minimise the handling of fruit will assist in reducing bruising of fruit. Where fruit is sold loose, the regular removal of poor quality fruit will reduce the desire of shoppers to pick over the display, further damaging fruit quality. Unit packaging that prevents the shopper from handling individual fruit eliminates this problem. It is important to note that none of these packing and retail strategies will improve fruit that was bruised or inherently soft to start with.

Rots Rots were a major problem in some lines of fruit in both survey years and was evident during a short storage period after purchase. The control of storage rots begins in the orchard where good orchard management such as targeted sprays and orchard hygiene can help minimise the disease pressures. Orchard strategies to minimise inoculum level and disease incidence are beyond the scope of this project, but are a key platform from which to achieve improved performance. Important harvest and postharvest strategies include; selective picking to minimise the percentage of decayed and cracked fruit entering the packing shed, rapid pickup and pre-cooling of fruit once harvested, prompt and correct use of appropriate sanitisers and fungicides, minimisation of bruising and physical damage during harvest and handling, maintaining temperature control through supply chain, as well as the correct use of modified atmosphere packaging and fungicides where appropriate.

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This work showed that rots were a significant problem with fruit that had been stored and therefore it is important to minimise the time in the supply chain between harvest and the consumer.

Firmness Orchard practices which encourage the production of firm sound cherries should be encouraged as no amount of care from the point of harvest will improve fruit that is inherently soft to begin with. Variability of fruit firmness between and within lines of fruit were identified in this study. It is recommended to choose varieties that have naturally firm fruit and apply orchard management practices that favour production of firm fruit. No amount of care from the point of harvest will improve fruit that is inherently soft to begin with. Prompt pre-cooling after harvest and subsequent best practice temperature management is an important means of retaining the firmness of fruit. Fruit should be harvested at its optimum maturity. Retail Temperature management is an important means of retaining the firmness of fruit. The use of refrigerated displays at the retail level will reduce the loss of fruit firmness and rapid stock rotation will also reduce the loss in firmness. Even where fruit is displayed at ambient temperature, its quick sale within hours of display will not allow time for the cherries to soften. Strategies at the retail level that minimise the handling of fruit assist in reducing bruising of fruit. Where fruit is sold loose the regular removal of poor quality fruit will reduce the desire of shoppers to pick over fruit, damaging it further. Unit packaging that prevents the shopper from handling individual fruit eliminates this problem. However none of these strategies will improve fruit that was inherently soft or had poor eating texture to start with. Presentation of good quality fruit to the consumer relies on producing good quality fruit from the orchard.

Stem condition Many of the practices required to maintain stem quality at the orchard, packing shed and through the supply chain well known. Control of stem damaging pests such as earwigs in the orchard can significantly improve stem quality. Other standard practices include harvesting early in the morning or during cool weather, prompt hydro-cooling and subsequent correct and continuous temperature management in association with the use of moisture barrier bags or modified atmosphere bags. The results in this survey showed there were many examples of poor stem on arrival at the store. In addition the survey results suggest that emphasis now needs to be placed on processes to maintain stem quality at the retail level.

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Retail Based on the observations made in this survey and the results of the stem quality experiments, it is clear that the retail storage conditions significantly affect stem quality. The use of refrigerated displays for cherries in conjunction with packaging significantly benefits fruit and stem quality. However its merits in terms of the impact on sales volumes and consumer perception and overall return of the category at a range of price points need to be investigated. In addition the different packaging technologies, including the potential of edible coatings need to be more fully explored. If fruit are to be sold in open displays, it is also important to educate consumers on the best methods to store their fruit when they get it home, ie leave the cherry fruit in the plastic shopping bag and keep them in the refrigerator.

Stem pull and stem loss As the factors behind stem retention are not fully understood, further investigation is required to determine the best strategies to improve the levels of stem retention.

Total soluble solids Fruit TSS is thought to be a key driver of consumer satisfaction and acceptance. Low fruit TSS as found in this survey can result in poor acceptance and loss of repeat sales. Some varieties are inherently sweeter than other varieties, increasing the likelihood of growing fruit that has sufficient sugar levels. In addition, harvesting fruit at the correct maturity for the variety is imperative to maximising fruit sugar levels. However there is a limit to the quantity of sugar a cherry tree can produce and it is difficult if not impossible to achieve satisfactory TSS levels in fruit harvested off overcropped trees. However orchard management practices such as irrigation, nutrition, management of tree vigour and growing systems can all contribute to improving fruit TSS levels. In addition, good postharvest practices such as maintenance of the cold chain and the use of modified atmosphere bags can also assist maintenance of TSS during storage and marketing. The industry would benefit from the development of a comprehensive production package on practical strategies to meet consumer expectations for TSS and fruit flavour.

Fruit acidity A greater understanding of the implications of fruit acidity levels on the marketplace is required before any substantial action should be taken. Consumer resistance has been found when certain cherries with distinctive flavours or high acidity have been previously marketed. Industry needs to be wary of establishing large commercial planting of new varieties until their flavour profile has been established as being suitable for the market for which they are being planted (whether low, medium or high acidity). In addition, more work is required on how fruit with different TA levels

164 behave in different supply chains. For example some evidence suggests that varieties with higher acid levels at harvest have a longer storage life and are more suitable candidates for longer distance marketing or storage.

Flavour The maintenance of taste and flavour is critical in satisfying consumers and ensuring repeat purchases. However fruit flavour is a complex quality attribute and the perception of flavour and consumer behaviour in response to flavour varies with the market and variety. There is a need to quantify the impact of varying flavour profiles have on price and volume of sales. It will then be possible to determine and implement strategies to lift the quality of cherries placed on the market above the minimum thresholds. The challenge of achieving this in the Australian cherry industry is substantial. Improving fruit quality will rely on what the consumer requires and is willing to pay for. In general it is thought that flavour is the balance of TSS and TA in the fruit, and this varies with the relative proportion of sugars. Little research has been conducted on consumer preferences with cherry TSS/TA and other fruit quality attributes. More research is required to identify what TSS, TA and the ratio of TSS/TA in different varieties are preferred by consumers, then pre- and postharvest management strategies can be developed to deliver these attributes.

6.2 Recommended R&D activities to address the key findings of the project

1. Continuous review, feedback and improvement of the domestic supply chain Continue to work with retailers to improve fruit quality and sales of Australian cherries. A survey of fruit quality issues in the 2010/11 and 2011/12 seasons has provided baseline data for the improvement of fruit quality. There is a need to continue this survey to measure improvements in the supply chain and to give confidence to retailers of high quality Australian cherries. In addition, surveys of the whole of supply chain, from orchard to consumer focussing on fruit quality and subsequent storage, are essential to identify potential issues affecting fruit and stem quality (such as pitting and bruising). The utilisation of this data in each season will provide strong base to develop and implement strategies to improve fruit quality. Utilising the knowledge gained from each season, a streamlined targeted approach could be used to verify and provide more in depth data on key issues. This strategy would enable the industry to focus research and development needs in relation to improving fruit quality. The development and implementation of through chain fruit quality systems will be essential for the growth of Australian cherry industry, particularly with the need of the industry to shift its focus to exports.

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Retail Fundamental to improving fruit quality to the consumer is the role of the retailer. It is essential that fruit quality is maintained through the chain from the orchard to the consumer. It is recommended that industry work closely with the entire supply chain to improve fruit quality and increase cherry sales. Specifically key research and development activities that quantify and improve fruit quality need to be undertaken. For example, the evaluation of different retail packaging and handling systems. This project showed that some types of packaging technologies were more effective at different temperatures than others. The appropriate packaging, handling and display of cherries need to be customised to each retail situation and recommendations and education of participants in the supply chain need to be developed and implemented. This is not only specific for the domestic market, but export markets also need to be addressed. Education will be crucial to improving fruit quality in the supply chain, particularly at the retail level. It is therefore recommended to develop, distribute and implement best practice supply chain guidelines. This recommendation is in addition to the development and implementation of best practice recommendations for industry (Recommendation 6 – below).

2. Develop a comprehensive package of practical strategies to improve packinghouse efficiency, minimise pitting and bruising, maintain stem quality, improve fruit firmness and minimise rots

Improve packinghouse and supply chain efficiencies There is a need to improve the efficiencies of postharvest activities in the supply chain from harvesting to the retail environment. Packinghouse efficiency and effectiveness in consistently delivering quality fruit, needs to be reviewed and improved. This study showed that the packing line activities had a large effect on fruit quality. Critical control points in the packing line need to be assessed, rectified and re-evaluated. In addition, it is important to improve the efficiency of the packinghouse to reduce costs and improve fruit quality. It is recommended to evaluate measures such as new packing technologies to improve the efficiency of the packing line. In addition, the use of modified atmosphere packaging needs to be reviewed for different handling systems and markets. The use of modified atmosphere packaging to generate a specific storage atmosphere around the fruit has been shown to be beneficial for fruit quality during long term storage, but these benefits need to be evaluated for all supply chains and markets.

Minimise fruit pitting and bruising Pitting and bruising were identified as major defects in fruit quality in the retail surveys in both seasons. The preliminary packingshed survey showed there were some significant issues that affect pitting and bruising in the packed fruit and these need to be rectified. The causes and solutions to the major defects need to be more closely examined and the results applied. The effect of variety, maturity, fruit quality

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(particularly firmness), preharvest and postharvest handling needs to be reviewed, analysed and implemented. Our current understanding of pitting is limiting our management of pitting. Although impact damage does affect pitting, numerous unknown factors also contribute to the development of pitting during storage and transport. Current research in Chile is developing predictive tools to sort and predict the effects of mechanical damage during storage. This research needs to be applied and trialled in Australia to find better ways to manage and reduce this damage to cherry fruit. In addition, fruit bruising is also a significant fruit quality issue and significant emphasis needs to be implemented at the retail level in collaboration with the major retailers. Managing fruit pitting and bruising will become an increasing important aspect of storage and fruit quality for Australian cherry exports and strategies must be implemented to ensure pitting and bruising are not barriers to the growth of the Australian cherry industry.

Maintain stem quality The results of the stem quality and retail display work (2011/12) clearly showed the strong interaction between storage and retail display environment (temperature, relative humidity and air flow rate) and stem quality. This should be followed up with the retailers and recommendations made. Stem quality at the retail level continues to be an issue and needs to be addressed in four ways: a) determine the relationship between storage and display environment to fruit and stem quality, b) explore the potential of edible coatings to maintain fruit and stem quality during handling, storage and retail display, c) review and investigate packaging options which optimise fruit and stem quality in a range of storage and retail conditions, and d) develop strategies for the supply chain, including the retailers, to maintain fruit and stem quality.

Improve fruit firmness Fruit firmness into the packingshed is determined by growing conditions and orchard practices. Variability of fruit firmness between and within lines of fruit was identified in this study. It is recommended to investigate orchard practices and varieties that favour production of firm fruit as no amount of care from the point of harvest will improve fruit that is inherently soft to begin with. Some standard benchmarks for fruit firmness use a 250 g/mm standard with the FirmTech instrument (airfreight transport, Australian Cherry Quality Guide, 2004). Periods of rainfall or intense or sustained heat before or at harvest can lead to substantial drops in the cherry firmness. There was a perception by the assessors that fruit was sometimes too soft even though the quantitative measurements made with the FirmTech instrument were above the benchmark. This may be due to: (1) the variability in firmness of individual cherries tasted by the assessors (rather than the average firmness value), (2) other textural properties of the cherries that were not measured with the FirmTech instrument, or (3) that the benchmark or firmness is not high enough. These observations require more investigation. The Firmtech instrument only measures deformation of the fruit, however fruit texture is complex

167 integrated sensory sensation. New techniques of measuring firmness and texture are available which may assist in determining fruit texture quality.

Minimise rots The development of postharvest rots is a significant issue, particularly in pre- weighted punnet style packaging. More data should be generated on the incidence, nature and type of postharvest rots. The current fruit surveys showed high level of postharvest rots in both survey seasons and were anecdotally due to the high rainfall and humid conditions at harvest. However more work is required to prevent postharvest rots becoming an issue.

3. Develop a comprehensive package of practical strategies to meet consumer expectations for TSS and fruit flavour Meeting consumer expectations There is surprisingly little practical information on what constitutes flavour / quality and especially what Australian consumers’ preferences, expectations and are willing to pay for quality. It is recommended to obtain sensory and consumer data of consumer satisfaction of Australian cherries. This work must also be directly linked to the willingness of consumers to pay. Due to the nature of this type of research, this work must be conducted strong scientific rigour. Specific issues to meet consumer expectations of Australian cherries Titratable Acidity The balance of sweetness and acidity (TSS/TA ratio) is an important factor in consumer satisfaction levels. Fruit with medium to high levels of acidity can be a positive trait, as long as the fruit has sufficient sugar levels to balance the flavour. In the absence of sufficient TSS, fruit having high acidity levels will be sour and have a negative impact on consumer satisfaction. Variety is the key determinant in the underlying acidity level of fruit. In addition, seasonal conditions such as rainfall at harvest can influence TA levels. There has been a trend in Australia towards the production of low to medium acidity varieties of cherries. Such varieties, though they may be regarded as bland by some consumers, carry little risk of a strong negative response from consumers. Contrast this to the apricot industry where significant damage to the marketplace has occurred from the prolonged marketing of overly acidic varieties. There has been insufficient sensory or consumer research conducted to ascertain if there are marketing opportunities in Australian or export markets for more strongly flavoured cherries characterised by slightly higher acidities. A greater understanding of the implications of fruit acidity levels on the marketplace is required before any substantial action should be taken. Consumer resistance has been found when certain cherries with distinctive flavours or high acidity have been previously marketed. Industry needs to be wary of establishing large commercial planting of new varieties until their flavour profile has been established as being suitable for the market for which they are being planted (whether low, medium or

168 high acidity). In addition, more work is required on how fruit with different TA levels behave in different supply chains. For example, there is some evidence that suggests that varieties with higher acid levels at harvest have a longer storage life and are more suitable candidates for storage. Total soluble solids TSS is a crucial determinant of fruit acceptability. However more data on the TSS levels across the season from different growing regions is required to obtain a stronger focus on what research and development is needed to improve TSS and fruit flavour. The low levels of fruit TSS during the 2010/11 season was considered to be inherent in the poor growing conditions of the year. However, further systematic collection of data is required to inform and test industry approaches to improve fruit TSS. This should be integrated into current knowledge and research projects such as ‘Optimising cherry fruit set, crop load and fruit nutrition and size’ (HA CY10002). This would provide valuable preharvest information to improve fruit TSS levels, and a broader approach with specific varieties and growing locations would help industry deliver fruit with TSS levels that consistently satisfies consumers. This should be developed into a package of practical strategies to assist industry meet consumer expectations for TSS and fruit flavour.

4. Develop a fruit quality decision matrix to provide objective information to assist fruit marketing Results of this survey highlight the challenge ahead of the cherry industry to consistently supply each market with fruit that meets or exceeds consumer expectations. In addition to developing and implementing specific strategies to improve the industry’s performance in meeting consumer expectations for individual quality parameters, the industry would benefit from the development of an Australian quality matrix for making marketing decisions. This will allow cherries to be objectively assessed for quality at harvest and the optimum market predicted based upon physiological quality parameters. Due to the vagaries of growing conditions and factors that cannot be fully controlled, industry will always be faced with marketing fruit with a range of different qualities. The development of objective systems for determining each line of fruits’ ultimate consumer acceptance for given markets along with the fruits potential storage and market life would assist industry participants to maximise the value of each season’s crop. The Chilean cherry industry has demonstrated the benefits of utilising a fruit quality decision matrix to assign fruit lots to markets based on a series of key quality indices. This needs to be applied and adopted in Australia.

5. Capitalising on international collaboration There are a small number of research groups working around the world on cherry fruit quality and market access. It is recommended to continue to work with these groups and utilise their experience and knowledge to improve the profitability of the Australian cherry industry. We have strong links with several research groups in Spain and the USA which have collaborated in this project (page 162). In addition,

169 there are several other research groups in Chile, USA and Turkey which have considerable experience in postharvest and market access and these potential resources should be applied to Australian conditions. For example Dr. Zoffoli’s cherry pitting work in Chile will lead to improved fruit quality after storage and transport, and it is important that the Australian industry benefits from this collaboration.

6. Supplement best practice postharvest and packinghouse operations into industry guidelines It is crucial that any recommendations and outcomes of research are adopted by industry. It is recommended that the best practice postharvest and packinghouse guidelines are integrated into existing extension plans and documents such as the Australian Cherry Production Guide and the Australian Cherry Export Manual. It will be important to work with all stakeholders in the supply chain to improve fruit quality and cherry sales.

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Acknowledgements

We wish to acknowledge and thank Woolworths for their co-operation and support. We acknowledge the assistance of Rocky Tassone and Daniel Snape for arranging access and assistance with this project. We also thank Coles supermarkets in SA and the independent fruit and vegetable grocers in SA and NSW. We would especially thank the produce managers and staff in each of the stores who generously helped throughout the retail surveys. We also acknowledge and thank the cherry growers of Young, Orange and the Adelaide Hills for this assistance and generosity in allowing access to their orchards and packing lines, and allowing samples of fruit to be assessed for the packingshed survey. We would like to thank for their expert technical assistance; Shashi Satyan, Matt Pearse, Mark Bullot, Kylie Crampton and Barbara Blades from NSW DPI and Darren Graetz from SARDI. We would also thank Lorraine Spohr and Anne Harris (NSW DPI) for their expert biometric analysis and support of this project. We also further thank Barbara Blades and Shashi Satyan for assistance with editing and improving this report. We also acknowledge and thank Adjunct Professor Barry McGlasson (University of Western Sydney) for his guidance, support and review of this report. This project was funded by the cherry levy facilitated by HAL in partnership with Cherry Growers of Australia Inc. The Australian Government provides matched funding for all HAL's research and development activities. NSW Department of Primary Industries and SARDI provided on-going support and significantly contributed to the outcomes of this project.

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References and further reading

AFFCO (2004). Australian Cherry Quality Guide. Cherry Growers Australia, Goulburn Valley Printing, Victoria.

APEC (2009) Asia-Pacific Economic Cooperation. Postharvest. A technology for living produce. Agricultural Technical Cooperation Working Group. ATC 02/2008A. APEC 209-AT-08.1 ISBN 978-981-08-3154-7.

Armstrong, P.R., Brown, G.K., and Timm, E.J. (1995). Nondestructive firmness measurement of soft fruit for comparative studies and quality control. American Society of Agricultural Engineering Paper 95 - 6172.

Australian Cherry Quality Guide (2004). Cherry Growers of Australia (CGA) and the Australian Fresh Fruit Company (AFFCO) Version 1.

Azarenko, A. (2005). Enhancing profitability with superior fruit quality. 36th National Cherry Conference, Tasmania.

Baker, C.A. (1982). Methylcellulose and sodium carboxymethylcellulose: Uses in paper conservation. Book and Paper Group Postprints 1: 16–19.

Bernalte, M.J., Hernandez, M.T., Vidal-Aragon, M.C. and Sabio, E. (1999). Physical, chemical, flavor and sensory characteristics of two sweet cherry varieties grown in 'Valle del Jerte' (Spain). Journal of Food Quality 22:403-416.

Couey, H.M. and Wright T.R. (1974) Impact bruising of sweet cherries related to temperature and fruit ripeness. HortScience. 9: 586.

Crisosto, C.H. (1992). Sweet cherry harvesting, postharvest handling and storage. Washington State University Tree Fruit Postharvest Journal 3: 3-6.

Crisosto, C.H., Crisosto, G.M. and Metheney, P. (2003). Consumer acceptance of ‘Brooks’ and ‘Bing’ cherries is mainly dependent on fruit SSC and visual skin color. Postharvest Biology and Technology 28:159–167.

Crisosto, C.H., Crisosto, G.M. and Ritenour, M.A. (2002). Testing the reliability of skin color as an indicator of quality for early season ‘Brooks’ (Prunus avium L.) cherry. Postharvest Biology and Technology 24:147–154.

Dever, M.C., MacDonald, R.A., Cliff, M.A. and Lane, W.D. (1996). Sensory evaluation of sweet cherry cultivars. HortScience 31(1): 150-153.

Dickinson, E. (2008). Hydrocolloids as emulsifiers and emulsion stabilizers. Food Hydrocolloids 23: 1473–1482.

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Drake, S.R. and Elfving, D.C. (2002). Indicators of maturity and storage quality of 'Lapins' sweet cherry. HortTechnology 12(4):687-690.

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