International Journal of Studies IJFS October 2015 Volume 4 pages 148–162

Training of SMEs for frozen food shelf life testing and novel smart packaging application for monitoring

Theofania Tsironia, Marianna Giannogloua, Eleni Platakoua, and Petros Taoukisa* a National Technical University of Athens, School of Chemical Engineering, Laboratory of and Technology, 5, Iroon Polytechniou, Zografou 15780, Athens, Greece *Corresponding author [email protected] Tel: +30-2107723171 Fax: +30-2107723163

Received: 10 July 2014; Published online: 18 October 2015 Invited paper from the 3rd International ISEKI Food Conference - ISEKI Food 2014 - Bridging Training and Research for Industry and the Wider Community - and Technology Excellence for a Sustainable Bioeconomy

Abstract

Application of an optimized cold chain management system for frozen products can be assisted by monitoring with Time Temperature Integrators (TTI). TTI are smart labels that cumulatively show the product history in an easily measurable, time-temperature dependent change. In the IQ-Freshlabel European project enzymatic and photochromic TTI were developed and tested for frozen products. Further to the technical objectives, training activities were implemented to provide information and training to the staff of Small and Medium-sized Enterprises (SMEs) regarding the properties of the developed TTI and their utilization within , transport, storage and sale. In total, more than 276 European companies and consumers representing the frozen , the packaging industry and food business operators were successfully trained. The objective of the present article is to describe a general methodology for frozen food shelf life testing and modelling, and the selection of appropriate TTI for specific . This document serves as a technical manual for SMEs, including a case study for frozen shrimp and application of enzymatic and photochromic TTI, aiming to build their capacities to understand and use TTI for frozen food products. The value of systematic modelling of the kinetics as well as the response of the TTI in building an effective chill chain management system is also demonstrated. The TTI response study allows a reliable optimization and selection of TTI to be correlated to the target food product for which accurate information on temperature dependence is available. Keywords: Cold chain; Frozen food; Shelf life; Smart packaging; Time temperature indicators

1 Introduction consumption. According to the Regulation (EU) No 1169/2011,“date of minimum durability of a Continuous monitoring and verification of the food means the date until which the food retains shelf life of food products is necessary and re- its specific properties when properly stored”. The quires the development of practical systems that food business operators are responsible for shelf can monitor, record and translate the temper- life determination for a specific food product un- ature effect of food quality from production to

Copyright ©2015 ISEKI-Food Association (IFA) 10.7455/ijfs/4.2.2015.a4 SMEs training for cold chain management 149 der defined storage conditions in the temperature trol over pallets, control over the cases of product range of the real cold chain. and, finally, over the individual packages at every It is well known that the quality of the food prod- step in distribution (Symons, 1994). uct that reaches the consumer would have dete- Application of an optimized quality and safety riorated during transportation and storage com- assurance system for the chilled and frozen dis- pared to the quality characteristics at the time tribution of products requires continuous mon- of production (Fu & Labuza, 1997; Gates, Eu- itoring and control of storage conditions, from daly, Parker, & Pittman, 1985). Temperature production to consumption. Smart packaging data from recent surveys showed that, despite systems can provide meaningful information on good practices, monitoring and control efforts, food quality, either indirectly (e.g. time temper- significant temperature fluctuations are observed ature integrators) or directly (e.g. freshness in- during distribution, retail and domestic storage. dicators) (Smolander, 2008). Time-Temperature More specifically, 40% of the total time of the Integrators (TTI) are inexpensive, active “smart profile temperatures of frozen fish products are labels” that can show an easily measurable, time- over the recommended temperature, varying be- temperature dependent change that reflects the tween -16°C and -12°C (Source: European Cold temperature history of a food product to which Chain Database-FRISBEE project, http://www. it is attached (Taoukis & Labuza, 2003). Their frisbee-project.eu/coldchaindb.html). Quality change is based on a physical, enzymatic, chem- changes of frozen foods, albeit relatively slow, ical or microbiological reaction and is expressed are very dependent on the storage temperature. by an irreversible colour change or a colour move- For example, 50% of degradation of vitamin C ment along a scale. The extent to which this in frozen green occurs in 153 days at change occurs is related to the duration and -20°C for spinach only in 8 days at -5°C, while amount of temperature increase. The visible re- the respective values for green beans are 311 and action of the TTI can thus indicate the time- 21 days (Giannakourou & Taoukis, 2003). It be- temperature history of the product, changing comes evident that temperature monitoring and faster at higher temperature increase. Commer- control within the cold chain is a prerequisite for cially available TTI are based on various reaction effective quality management and optimization. mechanisms (polymerisation, photochromic reac- In current practice, this is usually handled by re- tions, diffusion or enzyme reactions) (Taoukis, porting on the packages of frozen food arbitrary Doona, Kustin, Feeherry, et al., 2010). They are disclaimers, stating that if the food is stored al- usually applied in the form of labels on the pack- ways at -18°C, then the expiry date is valid (and aging and thereby act as an indicator. The pre- which in practice very rarely occurs), but at any requisite for application of TTI is systematic ki- other temperature the food has extremely short netic modelling of the temperature dependence shelf life (for example one week at 5°C). of shelf life of the target food products. Most The current philosophy for food quality opti- Small and Medium-sized Enterprises do not have mization is to introduce temperature monitor- sufficient data which would enable them to de- ing in an integrated, structured quality assurance termine the shelf life of their food products for system, based mostly on prevention, through known time-temperature conditions in the real the entire lifecycle of the product (Taoukis, Gi- cold chain. Additionally, similar kinetic study annakourou, & Tsironi, 2011). Ideally, what is needed for the TTI response. Based on re- would be needed is a cost effective way to either liable models of shelf life and the kinetics both maintain temperature or to individually moni- of the product and the TTI response, the effect tor the temperature conditions of food products of temperature can be monitored, and quantita- throughout distribution in order to indicate their tively translated to food quality, from production real quality. This could lead to an effective qual- to the point of consumption (Taoukis & Labuza, ity control of the cold chain, optimized stock ro- 1989a, 1989b; Taoukis, 2001). Most of the stud- tation and waste reduction, as well as enable the ies have been conducted on chilled food, mainly estimation of the remaining shelf life at differ- meat and fish products under isothermal and ent stages of the cold chain. This calls for con- dynamic temperature conditions simulating real

IJFS October 2015 Volume 4 pages 148–162 150 Tsironi et al. cold chain scenarios (Mai et al., 2011; Smolander, life testing and modelling, and the selection of Alakomi, Ritvanen, Vainionpaa, & Ahvenainen, appropriate TTI for specific foods. This docu- 2004; Tsironi, Gogou, Velliou, & Taoukis, 2008, ment aims to enable SMEs staff to acquire the 2011). necessary knowledge regarding the TTI technol- In the IQ-Freshlabel European project (http: ogy and their application in the food chain. //www.iq-freshlabel.eu/) enzymatic and pho- tochromic TTI were developed and tested for frozen products. Methodology was developed 2 Materials and Methods for selection of the optimum TTI design of spe- cific frozen fish products and their application 2.1 Frozen food shelf life testing was validated in cold chain simulating trials and in pilot studies (Giannoglou, Touli, Platakou, A first estimation of the shelf life of a specific Tsironi, & Taoukis, 2014). This project further food can be made based on literature review and to the technical objectives, aimed to educate the past experience. Shelf life testing experiments stakeholders (SMEs) regarding the properties of are designed to determine the shelf life of a the developed TTIs and their utilization within product under given conditions and validate food packaging, transport, storage and sale. The previous shelf life estimations. The target food training activities were addressed at first to SME products are produced and packed under the Associations (SME-AGs) that afterwards con- desired conditions. A sufficient amount of pack- ducted training to their members. The work- ages are stored at minimum three isothermal shops involved two phases: shelf life modelling of conditions in freezers with temperature control, frozen seafood and TTI theory and application. with the higher temperature reaching abuse Training material was developed, including an conditions that have been reported in the frozen extended training manual for frozen seafood shelf food chain (e.g. -5, -8 and -12°C) (Giannoglou life testing and application of TTI, PowerPoint® et al., 2014). Temperature in these controlled presentations and printed tutorials. The devel- freezers should be constantly monitored with oped training materials, adapted to the meat and appropriate data-loggers. This accelerated shelf fish producers’ needs in terms of content and life testing will enable the determination of language were distributed to the training atten- the relatively long shelf lives of frozen foods dees and published on the IQ-Freshlabel web- in shorter periods and will evaluate the effect site (http://iq-freshlabel.eu/402.0.html). Prac- of temperature abuse on the shelf life stability tical demonstrations of the activation of the of the product. In addition, kinetic studies at TTI were carried out during the trainings in several temperatures are necessary to predict order to provide the participants a visual and the effect of temperature fluctuations which may clearer idea of the TTI operation. The Work- occur in distribution and storage on the shelf life shop ”Smart packaging: Cold chain management of frozen foods. Control samples are also kept at for frozen food quality” was co-organized by the recommended frozen conditions (e.g. -18°C) to National Hellenic Association of Frozen Foods validate the predictions of the accelerated shelf (PASEKT) and National Technical University of life experiments. The number of samples and Athens on 26/9/2012. Forty-three SME mem- controls required should be based on a detailed bers were trained on TTI application to frozen experimental design. In general, at least 10 food products; the training was carried out us- packages per storage condition are required. ing the Greek language. The study involved two If large quantities of the food packages are phases: methodology for shelf life modelling of available, extra samples should be placed into frozen seafood and TTI theory and application. each storage condition (Fu & Labuza, 1997). The outcome was an increase in the technological Samples are taken at appropriate time intervals level of both the SME-AGs and the SMEs in the to allow for efficient kinetic analysis of quality addressed sectors. deterioration. The objective of the present article is to practi- Quality assessment of the target frozen food is cally describe a methodology for frozen food shelf based on several physicochemical parameters

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(i.e. colour, texture, pH, total volatile nitrogen- 2014). Chemical or instrumental measurement TVBN, lipid oxidation-TBARS). The selected that closely correlates to sensory changes can be quality indices can be based on literature review the criterion for shelf life evaluation. and previous experiments conducted on similar The Arrhenius equation (Equation1) is often products. The sensory attributes of frozen and used to describe the temperature dependence of cooked samples are evaluated by a sensory panel deterioration rate of 6-8. Thawed samples are cooked individu-    ally wrapped in aluminium foil, at 180°C for −EA 1 1 k(T )t = kref exp − (1) sufficient time (e.g. 20 min). Frozen products R T Tref should be first examined in the frozen state, where k is a pre-exponential factor which rep- especially for products packed in transparent ref resents the rate constant of the degradation of package. Panellists develop a list of profiling the respective quality index at a reference tem- attributes concerning appearance and odour of perature, T (e.g. -5°C for frozen foods), T is thawed samples and appearance, odour, texture ref the temperature in K, E is the activation en- and flavour of cooked samples. The sensory a ergy of the studied action indicating its temper- parameters are evaluated using descriptive terms ature dependence and R is the universal gas con- and recorded in appropriate forms, reflecting the stant (Taoukis, Labuza, & Saguy, 1997). Thus, organoleptic evolution of quality deterioration. by studying a deterioration process and mea- Rating is assigned separately for each parameter suring the rate of loss at two or three temper- on a 1 to 9 scale (9 being the highest quality atures (higher than storage temperature), one score and 1 the lowest). Additionally, panellists could then extrapolate on an Arrhenius plot to are asked to evaluate the overall impression and predict the deterioration rate at the desired stor- acceptability, using a 1 to 9 scale, indicating age temperature. This is the basis for accelerated the general impression of the product (frozen, shelf life testing (ASLT). However, it should be thawed and cooked). Samples were considered noted that for frozen foods extrapolation from acceptable if their score for overall impression temperatures above 0°C are meaningless for shelf were above 5 (medium quality), coinciding with life prediction (Fu & Labuza, 1997). slight off odour and off taste development. If a 1-3 scale is used, the limit of acceptability is set between 2 and 3 (FAO, 1995). The definition of 2.2 TTI response study shelf life and the criteria for the determination of the end of shelf life are dependent on specific A sufficient amount of TTI labels were obtained commodities and on the definition’s intended for use at three storage temperatures. The la- use (i.e. for regulatory vs. marketing purposes) bels were activated according to the guidelines (Barbosa, Bremner, & Vaz-Pires, 2002). given by the TTI provider and were adhered to The criterion for the limits of acceptability for a glass plate. Glass has high thermal capacity shelf life determination, based on the quality and thus the temperature of the labels during determining parameters, may be variable. the short time of measurement was not affected. Frozen foods degrade mainly by slow chemical Multiple TTI samples were isothermally stored reactions such as loss of nutritional value (e.g. in controlled freezers, e.g. at -5, -8 and -12°C. vitamin C content for some frozen fruits and Satisfactory temperature stability was achieved vegetables) or other chemical changes (e.g. with commercial freezers, by installation of high development of lipid oxidation resulting in the precision temperature controllers. The tempera- typical rancid taste). Values of the different ture profile of each freezer was recorded during measured indices are plotted vs time for all the experiments using low cost, programmable, temperatures studied and mathematical equa- downloadable data loggers. Testing of the TTIs tions that most adequately fit the data are was based on measurements, at appropriate time selected (FAO, 1995; Giannakourou & Taoukis, intervals of the colour change of multiple TTI 2003; Dermesonluoglu, Katsaros, Tsevdou, Gi- samples (3-5 samples per temperature, per en- annakourou, & Taoukis, 2015; Giannoglou et al., zyme concentration for the enzymatic and per

IJFS October 2015 Volume 4 pages 148–162 152 Tsironi et al. charging time for the photochromic TTI labels). initial green colour, becomes progressively yel- This could be carried out using a colorimeter, low/orange and reaches a final red colour. M- if available. Values of the different colour pa- type enzymatic TTI with different enzyme con- rameters (i.e. L, a, b) were plotted vs time for centrations (4 to 44U) were used and kinetically all temperatures studied and mathematical equa- modelled (Giannoglou et al., 2014). tions that most effectively describe their changes The OnVuTM TTI (B1 OnVuTM, Bizerba, Ger- were selected. Alternatively, visual evaluation of many) was based on the inherent reproducibility the TTI response changes could be conducted. of reactions in crystal phase (Patent EP 1049930 To assist this visual reading colour scales could B1). Photosensitive compounds, such as spiropy- be employed. rans, are excited and coloured by exposure to For this study multi point colour scales, one for low wavelength light. This coloured state (dark each type of the studied TTI labels, were con- blue) reverts to the initial colourless with a tem- structed and used for TTI colour evaluation by perature dependent reaction rate. By controlling the panel. For the construction of the colour the type of the photochromic compound and the scales, TTI labels were activated and left at length of UV light exposure during activation the T=25°C. When a colour change was visually ob- length and the temperature sensitivity of the TTI served, the colour of the TTI was instrumentally can be set (Tsironi et al., 2011). The B1 TTI measured and then the label was numbered and was charged (Bizerba Desktop Charger, Bizerba placed on a glass surface which was then stored at GmbH & Co. KG, Balingen, Germany) for 0.1 to -30°C. Thus, each label of the constructed colour 1 s (charging time of 1 s corresponds to energy of scales corresponded to a specific measurement of 50 mJ/cm2) and subsequently laminated with an colour (i.e. L, a, b). This procedure was re- optical filter (TTR 70QC) to protect TTI from peated for the whole range of colour change for light exposure and recharging (Giannoglou et al., each TTI type. To confirm that visual scoring 2014; Tsironi et al., 2011). gives results similar to the respective ones ob- tained by the instrumentally measured colour of the labels, panellists were asked to compare the 3 Results and Discussion labels’ colour with the numbered colour scale. The L, a, b values estimated by the colorime- 3.1 Frozen food shelf life testing ter were then compared to the L, a, b values of the label indicated by the panellists. The colour To more effectively describe the methodology scales should be stored at -30°C and they were for frozen food shelf life testing, frozen whole frequently checked to ensure colour stability (in unpeeled shrimp was presented as a test case. case of decolourisation of the TTIs the colour The experimental procedure was based on a scale must be replaced). The response time (i.e. previous shelf life study reported by Tsironi, time from activation to endpoint, as defined by Dermesonlouoglou, Giannakourou, and Taoukis the TTI provider) at each studied temperature (2009). The aim of this work was to evaluate was determined. the shelf life of whole frozen shrimp provided Two different TTI smart labels were studied by another food producer and validate the within IQ-Freshlabel project, the one was enzy- previously reported kinetic models. The exper- matic and the second a solid state photochromic imental design and the results of the current TTI. The enzymatic indicators’ function was experiment are presented below. Whole un- based on a colour change caused by a pH decrease peeled frozen shrimp (Penaeus notialis, size: that is due to the controlled enzymatic hydroly- 5, origin: Atlantic ocean, Easter central, FAO sis of a lipid substrate. The colour change of 34) packed in their usual commercial packages the M-type enzymatic TTI (M Check Point®, (cardboard lined with HDPE film, weight: 500 VITSAB, Malmo, Sweden) was due to a con- g) were obtained directly from the packer. 80 trolled enzymatic hydrolysis by a microbial li- packages in total were distributed and stored pase (Rhizopus Oryzae lipase) of a lipid substrate at controlled temperature cabinets (Sanyo (methylmyristate). This TTI changes from an MIR 553, Sanyo Electric Co, Ora-Gun,Gunma,

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Japan) at constant temperatures (-15, -12, -8 be between 15% and 20% to guarantee the and -5°C). Electronic, programmable, miniature final quality of frozen shrimp. Temperature data loggers (COX TRACER®, Belmont, NC) dependence of the rates of TBARs and sensory constantly monitored the temperature in the changes were adequately described by Arrhenius incubators. Measurements of selected quality kinetics (Equation1) in the temperature range indices were conducted during a 14-month studied (i.e. -5 to -15°C). The activation energy period, and data were analysed and modelled. values, Ea, were determined at 132.5 and 111.6 Before analysis, samples were thawed at room kJ/mol, respectively (Tref =-15°C). temperature. Thawing was accelerated by To define a threshold TBARs value for frozen immersion of the material in water. This is shrimp shelf life determination, Figures1a and acceptable if product is protected from the 1b were merged. A sensory score of 5 was taken contact with water by suitable wrappings, or if as the average score for minimum acceptability. contact with water does not materially affect As shown in Figure1c, the limit of sensory the sensory properties of the product (CAC/GL shelf life coincided with a TBARs value of 3 3, 1999). All determinations were made in mg MDA/kg. The shelf life of frozen shrimp duplicate samples. as determined based on sensory evaluation and 2-Thiobarbituric acid reactive substances TBARs changed as shown on Table1. Shelf life (TBARS), that evaluate lipid oxidation, has plots are practical and easier to understand as been considered as good quality index for frozen the shelf life of the food can be read directly at shrimp (Boonsumrej, Chaiwanichsiri, Tantra- any storage temperature. The shelf life of frozen tian, Suzuki, & Takai, 2007; Bono, Badalucco, shrimp at all storage temperatures is illustrated Cusumano, & Palmegiano, 2012). TBARS in Figure2. assay was performed according to the method developed by Lovaas (1992). TBARs were determined for thawed shrimp flesh. According to the methodology described above, from each 3.2 TTI response study test storage conditions (i.e. -5, -8, -12 and -15°C) TBARs and sensory scoring were plotted vs time (Figure1a and1b, respectively). Both changes The response time of the two types of TTI tested were described adequately by linear equations for use by SMEs for a target product as the stud- (R2 > 0.94 in all cases). Sensory scoring (overall ied frozen shrimp was determined using colour impression) decreased with time following zero scales consisting of TTIs at different levels of order kinetics (R2 > 0.97 in all cases). The colour change. These scales are shown in Fig.3a sensory characteristics at the point of organolep- and3b. End point colour was noted by a single tic rejection were sour, fish off flavours for the value in the scale of each TTI. For M-type enzy- cooked samples together with dry texture and matic TTI label end point value was 12 and for discolouration of shrimp shell in the thawed B1 photochromic TTI label end point value was product. Severe blackening in the head and 18. It was confirmed that visual scoring with the gill regions was observed after one month of use of such scales give results that do not differ storage at -5°C. All samples stored at lower that statistically from instrumental colour measure- -8°C had acceptable appearance before thawing ment. during storage. The results obtained at higher Based on the above described methodology, the storage temperatures (i.e. -5 and -8°C) indicated total response times (time from activation to slightly faster quality deterioration for frozen endpoint) of the studied TTI labels for the differ- shrimp than the respective data reported by ent enzyme concentrations or charging times and Tsironi et al. (2009), which was attributed to at different storage temperatures were illustrated lower amounts of ice glazing, species diversity, in Figures4a and4b respectively. It is evident sample orientation and fat content. Gon¸calves that the lower the enzyme concentration or the and Junior (2009) reported that a reasonable higher the charging time of the TTI, the longer range of water uptake during glazing could the shelf life at a given storage temperature.

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a)

b)

c) Figure 1: (a) Evolution of lipid oxidation (TBARs), and (b) sensory scoring (overall impression) of frozen shrimp during isothermal storage at -5, -8, -12 and -15°C. (c) Correlation of TBARs value with sensory scoring (overall impression) for the determination of TBARs limit for shelf life estimation (horizontal lines: average TBARs limit ± standard deviation)

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Figure 2: Shelf life (days) of frozen shrimp stored isothermally in the range -5 to -15°C

Table 1: Shelf life of frozen shrimp stored at -5, -8, -12, -15 and -18°C

Shelf life (d) Storage Sensory scoring TBARs temperature (limit=5 score) (limit=3 mg (°C) MDA/kg) -5 34 34 -8 67 68 -12 173 178 -15 359 374 -18* 758 799 *Calculated

3.3 Selection of appropriate TTI 4a and4b for frozen shrimp and the selected M- for monitoring the quality of 15U enzymatic and B1-0.15s photochromic label, frozen shrimp respectively. Practically, this required the TTI response kinetics to be similar to the kinetics of quality loss of the food product, which meant To select the appropriate enzyme concentration similar EA values. This close match is not always or charging time, based on the shelf life studies on observed as shown in Figure5, where the M-type the target frozen food product and the response enzymatic TTI were investigated to monitor the profiles of the TTI, the shelf life curves of the shelf life of frozen gilthead seabream (Sparus au- TTI and the food were combined to obtain an rata) fillets. In this case, a suitable TTI could be adequate match between the product shelf life selected if it showed satisfactory correlation with and the response time of the TTI label in the the target food product in the temperature range frozen range (e.g. -15°C), as shown in Figures of -5 to -12°C and at lower (recommended) stor-

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a)

b) Figure 3: (a) M-type enzymatic TTI label colour scale, (b) B1 photochromic TTI label colour scale)

age temperatures it showed higher response times 3.4 Validation of the applicability than the respective shelf life of the food. Based of the selected TTI for on this selection (i.e. M-10U enzymatic TTI for monitoring the quality of frozen gilthead seabream fillets), if the products were stored at very low temperatures (i.e. be- frozen shrimp at dynamic low -12°C) the end of shelf life would be deter- conditions mined and limited by the expiration date on the food package. On the other hand, if abuse tem- To validate the applicability of the selected TTI peratures prevailed, then the TTI would conser- for monitoring the quality of frozen shrimp in vatively signal poor quality products just before the real chill chain, a laboratory scale exper- the end of shelf life. In general, a TTI with an iment simulating abusive cold chain conditions EA within ±20 kJ/mol of the activation energy of storage was designed. The selected TTI (M- of the selected quality index of the target food 15U enzymatic and B1-0.15s photochromic la- product could be used to satisfactorily monitor bel) were attached on the frozen shrimp pack- its shelf life. ages, which were stored at controlled tempera- ture cabinets (Sanyo MIR 553, Sanyo Electric Co, Ora-Gun,Gunma, Japan) at variable temper- ature conditions. The time temperature scenario (Var) included repeated cycles of three isother- mal steps of 12 h each (i.e. 12 h at -5°C, 12

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a)

b)

Figure 4: Shelf life (days) of frozen shrimp at different storage temperatures (EA,shrimp=136.2 kJ/mol) together with the tested TTI response curves: (a) M-type enzymatic TTI (EA,M−type=111.6 kJ/mol) and (b) B1 photochromic TTI (EA,B1=123.2 kJ/mol)

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Figure 5: Shelf life (days) of frozen gilthead seabream fillets (EA,seabream=80.3 kJ/mol) together with the tested M-type enzymatic TTI response curves (EA,M−type=111.6 kJ/mol)

h at -8°C and 12 h at -10°C). Temperature in 15U enzymatic and B1-0.15s photochromic TTI, the incubators was constantly monitored with respectively), indicated that there was a good electronic, programmable miniature data loggers agreement between predicted and observed SLR (COX TRACER®, Belmont, NC). Samples were values. The validation experiment supported taken in appropriate time intervals. The re- the applicability of the selected TTI labels to sponse of the attached TTIs was estimated in monitor the quality of frozen shrimp under non- parallel with the quality deterioration of shrimp, isothermal conditions and hence in the dynamic in order to validate their effectiveness for moni- temperature conditions of the real chill chain. toring quality of frozen shrimp at dynamic con- The frozen food industry can significantly bene- ditions. The quality level and remaining shelf fit from the TTI technology. The quality changes life (at Tref =-15°C) at predetermined times was caused by exposure to higher than recommended estimated based on the response of the TTI (in- sub-zero temperatures result in considerable de- dicating the time-temperature history of the food crease of shelf life of the food products. The product) and the values were compared to actual expiration date ensures product quality only for measured values of the quality indices (TBARs storage under recommended conditions (below - and sensory evaluation) as shown in Fig.6. 18°C). However, during the post-production life The comparison between the experimental (ac- cycle of the frozen food products deviations af- tual) and predicted (calculated by the TTI mea- fecting the quality arise. Temperature monitor- surement) was based on the accuracy factor ing is the solution for improving the cold chain (Equation2) of the food products and decrease waste prior P |log(y /y ) to the expiration date. The selection of appro- accuracy factor = 10 predicted experimental n priate TTI labels for a particular product could (2) lead to realistic control of the cold chain, while where n is the number of observations. Perfect reliable estimation of the quality status and the agreement between predicted and observed val- remaining shelf life could be performed, allowing ues was represented by an accuracy factor of 1 better management and optimization from pro- (Ross, Dalgaard, & Tienungoon, 2000). duction to the point of consumption. Attached to The accuracy factors (1.033 and 1.012 for M-

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a)

b)

Figure 6: Correlation of the actual remaining shelf life in days (SLR−experimental) of frozen shrimp at Tref =-15°C estimated by experimental determination of quality deterioration (sensory evaluation) with the SLR−predicted calculated by the TTI response (a) M-15U enzymatic TTI (accuracy factor=1.033) and (b) B1-0.15s photochromic TTI (accuracy factor=1.012)

IJFS October 2015 Volume 4 pages 148–162 160 Tsironi et al. individual cases or pallets, TTI can provide in- to monitor cold chain more effectively by imple- formation regarding the preceding temperature menting experimental shelf life testing and by se- conditions at specific control points. This may lecting appropriate TTI smart labels for specific serve as a proof of compliance to contractual re- frozen food products. The training approach was quirements by the producer and distributor. TTI designed to offer the participants insights into can also guarantee the proper handling of food the theoretical background of frozen food qual- products during transportation and distribution, ity, current legislation and cold chain manage- thus eliminating the possibility of unsubstanti- ment. In total, more than 276 companies and ated rejection claims by retailers. At the same consumers representing the frozen food industry, time, TTI labels attached to the surface of a food the packaging industry, the meat industry, the package intend to integrate the cumulative time- seafood industry and food business operators in temperature history of the specific food product Greece, Finland, Romania, Poland, France and throughout the whole cold chain, from produc- Norway were successfully trained. Through the tion to the point of consumption, and hence pro- publication of the training material translated in vide information on the food quality. various languages, further impact on the Euro- pean chilled and frozen food products chain was reached. 4 Conclusions Acknowledgements Overall, the methodology for shelf life testing of frozen foods and the response of TTI smart labels This study was supported by the European Com- was demonstrated. Based on the storage tests re- mission FP7 Collective Research Project IQ- sults, appropriate TTI were selected for monitor- Freshlabel “Developing novel intelligent labels ing the quality of frozen shrimp, as a case study. for chilled and frozen food products and pro- Furthermore, the value of systematic modelling moting the influence of smart labels application of the food quality kinetics as well as the response on waste reduction, food quality and safety in of the TTI in building an effective chill chain the European supply chains” FP7-SME-2008-2- management system was also demonstrated. The 243423 (http://www.iq-freshlabel.eu). TTI response study allowed a reliable optimiza- tion and selection of TTI to be correlated to the target food product for which accurate informa- References tion on temperature dependence is available. To Barbosa, A., Bremner, A., & Vaz-Pires, P. cumulatively reflect the quality changes of the (2002). Safety and quality issues in fish pro- frozen food product, the required TTI should cessing. (Chap. The meaning of shelf-life, have a total response time of many months at - pp. 173–190). Woodhead Publishing Lim- 18°C and several weeks at -5°C to -8°C. If the TTI ited Cambridge, UK. response is not long enough, properly stored and Bono, G., Badalucco, C. V., Cusumano, S., & of good quality, products will be falsely indicated Palmegiano, G. B. (2012). Toward shrimp as having problem. Thus, the smart food labels without chemical additives: a combined are one way of effective communication of qual- freezing-map approach. LWT-Food Science ity status and risk associated with food product and Technology, 46 (1), 274–279. doi:10 . to food retailers and consumers. Moreover the 1016/j.lwt.2011.09.020 application of TTI that monitors the quality of Boonsumrej, S., Chaiwanichsiri, S., Tantratian, food contributes to the traceability approaches S., Suzuki, T., & Takai, R. (2007). Ef- and fills the gap of missing information between fects of freezing and thawing on the quality the different stages of the supply chain. changes of tiger shrimp (penaeus monodon) The IQ-Freshlabel training courses were devel- frozen by air-blast and cryogenic freezing. oped to provide SMEs with skills in the frozen Journal of , 80 (1), 292– food shelf life evaluation and cold chain man- 299. doi:10.1016/j.jfoodeng.2006.04.059 agement. The training encouraged participants

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