Effect of L-Glucose and D-Tagatose on Bacterial Growth in Media and a Cooked Cured Ham Product

Home , Tagatose

Journal of Food Protection, Vol. 63, No. 1, 2000, Pages 71±77 Copyright ᮊ, International Association for Food Protection

DERRICK A. BAUTISTA,* RONALD B. PEGG, AND PHYLLIS J. SHAND

Saskatchewan Food Product Innovation Program, Department of Applied Microbiology and Food Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, Saskatchewan, Canada S7N 5A8

MS 99-96: Received 9 April 1999/Accepted 17 August 1999

ABSTRACT Downloaded from http://meridian.allenpress.com/jfp/article-pdf/63/1/71/1669933/0362-028x-63_1_71.pdf by guest on 25 September 2021

Cured meats such as ham can undergo premature spoilage on account of the proliferation of lactic acid bacteria. This spoilage is generally evident from a milkiness in the purge of vacuum-packaged sliced ham. Although cured, most hams are at more risk of spoilage than other types of processed meat products because they contain considerably higher concentrations of carbohydrates, ϳ2 to 7%, usually in the form of dextrose and corn syrup solids. Unfortunately, the meat industry is restricted with respect to the choice of preservatives and bactericidal agents. An alternative approach from these chemical compounds would be to use novel carbohydrate sources that are unrecognizable to spoilage bacteria. L-Glucose and D-tagatose are two such potential sugars, and in a series of tests in vitro, the ability of bacteria to utilize each as an energy source was compared to that of D-glucose. Results showed that both L-glucose and D-tagatose are not easily catabolized by a variety of lactic bacteria and not at all by pathogenic bacteria such as Escherichia coli O157:H7, Salmonella Typhimurium, Staphylococcus aureus, Bacillus cereus, and Yersinia enterocolitica. In a separate study, D-glucose, L-glucose, and D-tagatose were added to a chopped and formed ham formulation and the rate of bacterial growth was monitored. Analysis of data by a general linear model revealed that the growth rates of total aerobic and lactic acid bacteria were signi®cantly (P Ͻ 0.05) slower for the formulation containing D-tagatose than those containing L-orD-glucose. Levels of Enterobacteriaceae were initially low and these bacteria did not signi®cantly (P Ͻ 0.20) change in the presence of any of the sugars used in the meat formulations. Compared to the control sample containing D-glucose, the shelf life of the chopped and formed ham containing D-tagatose at 10ЊC was extended by 7 to 10 days. These results indicate that D-tagatose could deter the growth of microorganisms and inhibit the rate of spoilage in a meat product containing carbohydrates.

Meat and meat products can be extremely perishable. cle is quite low (i.e., 0.90% lactic acid, 0.17% glucose-6- As such, methods are employed throughout the industry to phosphate, 0.10% glycogen, 0.01% glucose, and traces of retard deteriorative changes and to extend the period of ribose from the degradation of ATP, nucleotides and nucle- their acceptability. These techniques constitute various osides (8)), carbohydrates may be added to further pro- forms of meat preservation. A number of ingredients com- cessed meat products to give characteristic ¯avor and re- monly added to meat products during processing impart duced water activity. Unfortunately, the carbohydrate sup- preservative effects but to varying degrees. For example, plement can allow microorganisms, such as lactic acid bac- salt provides a limited preservative action against micro- teria, to grow and cause spoilage problems (7). Although organisms by lowering water activity; nitrite bestows lactic acid bacteria are desirable in fermented meat prod- marked bacteriostatic properties and when added at reduced ucts, in nonfermented ones their development contributes levels, it functions synergistically with salt to give certain to undesirable qualities. Moreover, these organisms can cured meat products effective preservation; sugar added to grow under low oxygen conditions and are therefore a ma- fermented sausages indirectly serves as a preservative due jor concern in vacuum-packaged meat products. to the lactic acid formed by starter cultures that results in Incidences of spoilage can be prevented or at least min- lower pHs; and various constituents of wood smoke impart imized with the introduction of food-grade chemicals to bacteriostatic and bactericidal effects (3). retard the onset of microbial colonization. Many researchers Yet, the proliferation of bacteria results in the prema- have attempted to suppress bacterial spoilage in meat using ture spoilage of food and continues to cause economic loss- synthetic organic compounds as preservatives. In the es for the industry (14). For one company, the annual loss health-conscience 1990s, the perception of natural is a key in revenue from a cured meat product due to souring was issue among consumers, especially when it has to do with deemed to be in excess of $100,000 (1). Such problems lie their food supply. As such, the addition of synthetic pre- mostly with undesirable fermentation of cured meat prod- servatives and bactericidal agents to meat does not accom- ucts containing high carbohydrate levels (7). Although typ- modate this view. ical endogenous carbohydrate in postrigor mammalian mus- An approach to retard spoilage and thereby extend the * Author for correspondence. Tel: 306-966-7804; Fax: 306-966-8898; shelf life of meat products is the exploitation of hurdle tech- E-mail: [email protected]. nology. Using this stratagem, one manipulates the environ- 72 BAUTISTA ET AL. J. Food Prot., Vol. 63, No. 1

Both L-glucose and D-tagatose exhibited no toxic, carci- nogenic, or teratogenic effects in tests carried out under conditions speci®ed by the U.S. Food and Drug Adminis- tration (10). Currently, the generally-recognized-as-safe sta- tus of D-tagatose is being assessed by the Food and Drug Administration. The purpose of this investigation was to evaluate the potential of L-glucose and D-tagatose to reduce the proliferation of bacteria in food systems. The growth of a variety of bacteria was tested in vitro in systems containing these alternative sugars and in situ in a simulated chopped and formed ham product to determine if the product's shelf life could be extended. Downloaded from http://meridian.allenpress.com/jfp/article-pdf/63/1/71/1669933/0362-028x-63_1_71.pdf by guest on 25 September 2021 MATERIALS AND METHODS

Preparation of bacteria for carbohydrate test. For each FIGURE 1. Fischer and Haworth projections of D-glucose, L-glu- bacterium listed in Table 1, a loopful (ϳ10 ␮l) of frozen culture cose, and D-tagatose. was inoculated into a test tube containing 1.5 ml of either brain heart infusion broth (Difco Laboratories, Detroit, Mich.) or MRS broth (Difco) to enrich for gram-negative and gram-positive bac- ment of meat to prevent the onset of growth of spoilage teria, respectively. The culture was incubated at 35ЊC overnight organisms. In the case of lactic acid bacteria, a fermentable (ϳ8 to 12 h) prior to the carbohydrate test. carbohydrate source is required for energy (3). By remov- ing that source, the growth of these organisms can be sup- Carbohydrate test to determine utilization of various sug- pressed. For meat products containing high levels of sugar ars by bacteria. D-Glucose (control) was purchased from Difco Laboratories while L-glucose and D-tagatose were acquired from (ϳ2 to 7%) as part of the formulation (e.g., ham), substi- MD Food Ingredients (Union, N.J.). All sugars were prepared as tution of the carbohydrate source to one that is not recog- a 5% (wt/wt) stock solution and ®lter sterilized. The utilization of nizable by bacteria represents a hurdle to their growth. these monosaccharides by a variety of bacteria was examined us- There are several new candidate sweeteners developed for ing a simple carbohydrate assay by bromocresol purple (i.e., 5Ј,5Љ- food applications with a signi®cant reduction in metaboliz- dibromo-o-cresolsulfonephthalein [bromocresol purple]; J. T. Bak- able energy. An example of such a sugar is L-glucose (Fig. er Chemical, Co., Phillipsburg, N.J.) as a pH indicator. This acid- ϩ s ϩ ϩ Ϫ 1). It is an enantiomer of the naturally occurring D-glucose, type indicator (HIn H2O H3O In ) can operate in pH has a sweetness ϳ0.6 times that of sucrose, and offers no ranges from 5.2 to 6.8. A change in color from purple to yellow available energy when metabolized by humans (11). A sec- indicates a reduction in pH and hence, carbohydrate utilization. Therefore, the term ϩ was used to denote a strong positive re- ond and most promising alternative sugar is D-tagatose (Fig. ϩ 1). It is a full-bulk naturally occurring monosaccharide that action when the system appeared completely yellow and ( )to denote a weak positive reaction when only a slight yellowness can be derived from whey or lactose and has a sucroselike was observed. The (ϩ) term implies that the bacterium in question taste (n.b., sweetness 0.92 times that of sucrose) with no could utilize the monosaccharide as an energy source but only to cooling effect, aftertaste, or potentiation of off ¯avors (9). a limited degree under the experimental conditions employed. Unlike D-glucose, D-tagatose is a ketohexose and a 4-epi- When the microorganisms could not utilize the test monosaccha- mer of D-fructose; in cyclic form, it exists as a pyranose, ride, then the system remained purple in color and a negative whereas D-fructose is predominately found as a furanose. reaction, Ϫ, was recorded.

TABLE 1. List of bacteria used to determine carbohydrate utilization Bacteria Collection type Bacteria Collection type

Lactobacillus frigidus NCIBa 8518 B. subtilis Lab strain L. plantarum ATCCb 10241 Listeria innocua ATCC 4616 L. acidophilus ATCC 53103 L. monocytogenes (Scott A) Lab strain L. brevis Lab strain Brochothrix thermosphacta Lab strain Pediococcus damnosus ATCC 29358 Moraxella spp. Lab strain Leuconostoc mesenteroides BSOc 117 Pseudomonas aeruginosa Lab strain Staphylococcus aureus ATCC 25923 Salmonella Typhi Lab strain S. aureus ATCC 13565 E. coli O157 Hospital strain S. aureus ATCC 25923 E. coli O157:H7 ATCC 43895 Bacillus cereus Lab strain Yersinia enterocolitica Lab strain a National Collection of Industrial Bacteria. b American Type Culture Collection. c Brewing Spoilage Organism. J. Food Prot., Vol. 63, No. 1 GLUCOSE AND TAGATOSE EFFECTS ON BACTERIAL GROWTH 73

TABLE 2. Meat formulation for the chopped and formed ham (i.e., semimembranosus) and pork fat (ϳ1 kg) were obtained from a local meat-processing facility for each experimental run. The Percentage Ingredient cushions and fat were ground separately through a ⅛Љ plate twice 71.80 Meat using a Biro meat grinder (model AFMG-24, The Biro Mfg. Co., 7% pork fat Marblehead, Ohio). A list of ingredients for the chopped and 93% pork cushions formed ham can be found in Table 2. The comminuted meat was 21.95 Water divided into three separate lots and the appropriate monosaccha- 3.50 Sugar (i.e., either D-glucose, L-glucose, or D- ride (i.e., either D-glucose, L-glucose, or D-tagatose) was used in tagatose) each preparation. All ingredients for the chopped and formed ham 2.00 Sodium chloride (food grade) were blended at 4ЊC in a mixer (model N-50, The Hobart Man- 0.38 Sodium tripolyphosphate (food grade) ufacturing Company Ltd., Toronto, Ontario) for 2 min. From each 0.31 Prague powdera preparation, 15 g of uncooked ham were stuffed into several poly- 0.06 Sodium erythorbate ethylene/polyamide bags (Barrier Packaging Inc., Delta, British Columbia) and gently pushed toward the posterior of the bag to a Prague powder that was obtained from Grif®ths Laboratories form circular tubes of meat. The batter was manipulated to remove Downloaded from http://meridian.allenpress.com/jfp/article-pdf/63/1/71/1669933/0362-028x-63_1_71.pdf by guest on 25 September 2021 (Mississauga, Ontario) contains 93.6% sodium chloride as well all air pockets, and the bags were sealed using a RoÈschermatic as trace amounts of sodium bicarbonate and glycerine as a man- vacuum packager (type VM-20, RoÈscherwerke GmbH, Osna- ufacturing aid and 6.4% sodium nitrite. bruÈck, Germany) to ensure a closed system and then cooked in a water bath set at 74ЊC to an internal temperature of 72ЊC(ϳ2to Overnight cultures were inoculated into media containing nu- 3 min). The temperature was monitored using an Omega micro- trient broth (Difco) supplemented with the indicator and one of processor thermometer (model HH21, Omega Environmental Inc., the test sugars at a ®nal concentration of 1% (wt/wt). A list of Laval, QueÂbec) with a type T thermocouple. After thermal pro- Њ ϭ microorganisms investigated is presented in Table 1. Bacteria ca- cessing, samples were cooled and then stored at 10 C(n 8) and Њ ϭ pable of utilizing the monosaccharide for energy will cause the 22 C(n 5) to promote growth of psychrotrophic and mesophilic pH of the media to drop, and this is denoted by a color change organisms in the ham product, respectively (5, 6). Samples stored Њ from purple to yellow. Samples were incubated up to 48 h at 35ЊC at 10 C were analyzed on a weekly basis for 8 weeks and those Њ under aerobic and anaerobic (Gas Pak System, BBL, Cockeys- at 22 C were tested every second day for a period of 10 days. ville, Md.) conditions. The carbohydrate assay was repeated in Three complete replications were performed for each product. triplicate for each bacterium. Proximate analysis of chopped and formed hams. Of®cial Preparation of chopped and formed hams with a different methods (4) were used for the determination of moisture (method type of sugars. Fresh pork cushions (ϳ1 kg) from leg muscle 950.46), crude protein (method 981.10), fat (method 960.39), and

TABLE 3. Carbohydrate utilization of various bacteria under aerobic and anaerobic conditions at 37ЊC Aerobic conditionsa Anaerobic conditionsa

Bacteria D-Glucose L-Glucose D-Tagatose D-Glucose L-Glucose D-Tagatose

Lactobacillus frigidus ϩϩϩb ϪϪϪc ϪϪϪ ϩϩϩ ϪϪϪ ϪϪϪ L. plantarum ϩϩϩ (ϩ)(ϩ)(ϩ)d (ϩ)(ϩ)(ϩ) ϩϩϩ (ϩ)(ϩ)(ϩ)(ϩ)(ϩ)(ϩ) L. acidophilus ϩϩϩ (ϩ)(ϩ)(ϩ)(ϩ)(ϩ)(ϩ) ϩϩϩ (ϩ)(ϩ)(ϩ)(ϩ)(ϩ)(ϩ) L. brevis ϩϩϩ (ϩ)(ϩ)(ϩ)(ϩ)(ϩ)(ϩ) ϩϩϩ (ϩ)(ϩ)(ϩ)(ϩ)(ϩ)(ϩ) Pediococcus damnosus ϩϩϩ (ϩ)(ϩ)(ϩ)(ϩ)(ϩ)(ϩ) ϩϩϩ (ϩ)ϩ(ϩ)(ϩ)(ϩ)(ϩ) Leuconostoc mesenteroides ϩϩϩ (ϩ)(ϩ)(ϩ)(ϩ)(ϩ)(ϩ) ϩϩϩ (ϩ)(ϩ)(ϩ)(ϩ)(ϩ)(ϩ) Staphylococcus aureus ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ ϪϪϪ ϪϪϪ S. aureus ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ ϪϪϪ ϪϪϪ S. aureus ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ ϪϪϪ ϪϪϪ Bacillus cereus ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ ϪϪϪ ϪϪϪ B. subtilis ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ ϪϪϪ ϪϪϪ Listeria innocua ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ (ϩ)(ϩ)(ϩ)(ϩ)(ϩ)(ϩ) L. monocytogenes (Scott A) ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ (ϩ)(ϩ)(ϩ)(ϩ)(ϩ)(ϩ) Brochothrix thermosphacta ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ ϪϪϪ ϪϪϪ Moraxella spp. ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ ϪϪϪ ϪϪϪ Pseudomonas aeruginosa ϩϩϩ ϪϪϪ ϪϪϪ N/Ae N/A N/A Salmonella Typhi ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ ϪϪϪ ϪϪϪ E. coli O157 ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ ϪϪϪ ϪϪϪ E. coli O157:H7 ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ ϪϪϪ ϪϪϪ Yersinia enterocolitica ϩϩϩ ϪϪϪ ϪϪϪ ϩϩϩ ϪϪϪ ϪϪϪ a The data in each column indicate the results of triplicate tests. b Represents carbohydrate utilization by the bacterial strain (i.e., a strong positive reaction). c Represents no carbohydrate utilization. d Represents carbohydrate utilization but as a weak positive reaction. e Not applicable. 74 BAUTISTA ET AL. J. Food Prot., Vol. 63, No. 1 Downloaded from http://meridian.allenpress.com/jfp/article-pdf/63/1/71/1669933/0362-028x-63_1_71.pdf by guest on 25 September 2021

FIGURE 2. Levels of (A) total aerobic bacteria, (B) lactic acid FIGURE 3. Levels of (A) total aerobic bacteria, (B) lactic acid bacteria, and (C) Enterobacteriaceae in chopped and formed ham bacteria, and (C) Enterobacteriaceae in chopped and formed ham formulations with different monosaccharides (⅜, D-glucose; Ⅺ, formulations with different monosaccharides (⅜, D-glucose; Ⅺ, L-glucose; ᭝, D-tagatose) stored at 10ЊC for 42 days. L-glucose; ᭝, D-tagatose) stored at 22ЊC for 10 days. ash (method 920.153). Carbohydrate was calculated by difference. 22ЊC for up to 3 days and counted. MRS agar plates were incu- The pH of ham samples was determined in duplicate by blending bated under microaerophilic conditions (5% O2, 10% CO2, 85% 20 g of the product (i.e., pooling from three samples) with 80 ml Њ N2)at35C for up to 3 days and counted. The detection limit for of distilled water in an Osterizer blender (model 1548, Sunbeam this assay is ϳ200 CFU/g. Corporation [Canada] Limited, Toronto, Ontario) for 1 min and then reading the pH using an Accumet combination electrode in Statistical design and analyses. The experiment was con- duplicate (Accumet pH meter 915, Fisher Scienti®c Co., Nepean, ducted as a split plot factorial design in which the main effects Ontario). were temperature during storage and type of monosaccharide used in the meat formulation. The general linear model procedure Microbiological analyses. For each time interval, samples (PROC GLM) of SAS (13) was used to assess the effect of storage (15 g) were diluted 1:10 with 0.1% (wt/wt) peptone water (Difco) temperature, type of sugar in the formulation, and interactive ef- and stomached (Stomacher Lab Blender 400, Seward Medical fects on bacterial growth of total aerobic bacteria, lactic acid bac- Limited, London, UK) at the normal setting for 120 s. The dilu- teria and Enterobacteriaceae. The following model was used to tions were plated onto plate count agar (Difco), MacConkey's agar interpret the data: (Difco), MRS agar (de Man, Rogosa, Sharpe, Unipath Inc., Ne- ϵ␤ ϩ ϩ ϩ pean, Ontario) in duplicate for total microbial, Enterobacteriace- SLOPE(mGijk) 0 trialijtreat temp k ae, and lactic acid bacteria counts, respectively, using a Spiral ϩ (treat ϫ temp) ϩ⑀ Plater (model D, Spiral Systems, Inc., Cincinnati, Ohio). Plate ij ␤ count and MacConkey agar plates were incubated aerobically at where SLOPE(mG)ijk refers to the rate of growth over time, 0 is J. Food Prot., Vol. 63, No. 1 GLUCOSE AND TAGATOSE EFFECTS ON BACTERIAL GROWTH 75

TABLE 4. Standard errors of bacterial population means during each time interval for each different sugar type used in the chopped and formed ham stored at 10ЊC Time (days) Carbohydrate Microbial population used 0 7 14 21 29 35 42

Total D-Glucose 0 1.50 1.10 1.66 1.87 1.80 2.31 L-Glucose 0 1.80 1.14 2.10 3.11 2.11 1.56 D-Tagatose 0 000000.98 Lactic acid bacteria D-Glucose 0 0 1.11 1.50 2.12 1.34 1.32 L-Glucose 0 0 0 0.74 1.22 1.45 1.14 D-Tagatose 0 00000.98 1.12 Enterobacteriaceae D-Glucose 0 000000 L-Glucose 0 0 0.34 0.21 0.12 0.15 0.15

D-Tagatose 0 000000 Downloaded from http://meridian.allenpress.com/jfp/article-pdf/63/1/71/1669933/0362-028x-63_1_71.pdf by guest on 25 September 2021

the intercept value, triali is the effect of the experimental run, treatj 93.3% in the glucose group (12). Similar results of Sal- is the effect of treatment of either D-glucose, L-glucose, or D- monella Typhimurium reduction in broiler chickens fed tagatose, tempk is the effect of storage temperature at either 10 or lactose from whey or nonfat dried milk were reported by Њ ϫ 22 C, (treat temp)ij is the effect of the combination of treatment DeLoach et al. (2). ⑀ and temperature conditions, and is the error term. Proximate analysis of chopped and formed hams for RESULTS AND DISCUSSION each formulation revealed similar values. The mean percentage of moisture, crude protein, fat, ash, and carbohy- Results of the in vitro carbohydrate test on various bac- drate in thermally processed products was 74.4, 14.9, 3.8, teria under aerobic and anaerobic conditions are presented 3.5, and 3.4, respectively. The carbohydrate difference (i.e., in Table 3. As shown from this carbohydrate test, only a 3.4%) was in close agreement with the amount of sugar few lactic acid bacteria, namely Lactobacillus plantarum, added. The pHs of cooked hams varied slightly (xÅ ϭ 6.3 L. acidophilus, L. brevis, Pediococcus damnosus, and Leu- Ϯ 0.2) with the meat block used for each replicate but were conostoc mesenteroides, had the ability to use L-glucose or similar for each formulation. D-tagatose as an energy source under both aerobic and an- The effect of monosaccharide on the microbial popu- aerobic conditions. However, carbohydrate utilization by ei- lation over time at 10 and 22ЊC in the simulated ham prod- ther L-glucose or D-tagatose was not as strong compared to ucts is illustrated in Figures 2 and 3, respectively. Based that of D-glucose. It is interesting to note that Staphylococ- on standard errors in Tables 4 and 5, only D-tagatose was cus aureus, Listeria innocua, L. monocytogenes Scott A, able to demonstrate a better level of consistency. Using sta- Bacillus cereus, Salmonella Typhi, Escherichia coli O157: tistical analyses (13), a nonlinear expression was employed H7, and Yersinia enterocolitica were unable to utilize L- to assist in interpreting the results. The level of signi®cance glucose or D-tagatose in the carbohydrate-supplemented was improved (P Ͻ 0.05) when a secondary log transfor- medium under aerobic conditions. Similar results were ob- mation of the data was used to determine differences in served under anaerobic conditions; however, both L. inno- bacterial growth rates. cua and L. monocytogenes Scott A exhibited slight utili- The analysis of growth rates of the various microbial zation of L-glucose and D-tagatose. Under the speci®c ex- populations using a modi®ed general linear model proce- perimental conditions employed, these in vitro tests show dure (13) showed that sugar type had a signi®cant (P Ͻ that bacteria have a limited capability to use L-glucose and 0.01) effect on the growth of total aerobic and lactic acid D-tagatose as a carbohydrate source. bacteria in the chopped and formed ham product at psy- Although little research has been reported on the in- chrotrophic (10ЊC) and mesophilic (22ЊC) temperatures (Ta- ability of bacteria to utilize D-tagatose and L-glucose, oth- ble 6). The level of bacteria observed on both MRS and er papers cited in the literature have shown that bacteria plate count agar indicated that the micro¯ora were predom- in various environments can have dif®culty utilizing inantly lactic acid bacteria in nature. The ef®cacy of inhi- nontraditional sources of carbohydrate as a substrate. In bition of micro¯oral growth was D-tagatose Ͼ L-glucose ϭ one study for example, the effect of mannose and lactose D-glucose (P Ͻ 0.05) at both temperature conditions. in the drinking water of broiler chickens at 2.5% (wt/vol) Therefore, the results suggest that D-tagatose retards the on Salmonella Typhimurium colonization was evaluated. growth of spoilage bacteria, namely lactic acid bacteria, in Results indicated that both sugars signi®cantly reduced in- a packaged ham product under psychrotrophic temperatures testinal colonization of the bacterium by at least one-half (10ЊC). as compared to glucose, maltose, and sucrose. Cecal Enterobacteriaceae counts on MacConkey's agar swabs showed that Salmonella Typhimurium was present showed that the monosaccharides had no signi®cant (P Ͼ only in 53.3% and 26.6% of birds that had been admin- 0.20) effect on growth. It is interesting to note that most istered lactose and mannose, respectively, compared to Enterobacteriaceae do not require a carbohydrate source 76 BAUTISTA ET AL. J. Food Prot., Vol. 63, No. 1

TABLE 5. Standard errors of bacterial population means during each time interval for each different sugar type used in the chopped and formed ham stored at 22ЊC Time (days) Carbohydrate Microbial population used 0 7 14 21 28 35 42

Total D-Glucose 0 1.51 2.19 2.25 0.94 1.87 1.24 L-Glucose 0 1.85 2.19 2.07 1.01 2.02 1.64 D-Tagatose 0 0 2.00 1.90 0.73 1.13 1.43 Lactic acid bacteria D-Glucose 0 1.23 1.18 1.23 3.20 2.20 1.54 L-Glucose 0 0 2.19 1.14 2.26 1.56 1.14 D-Tagatose 0 0 0 1.23 2.05 1.05 1.21 Enterobacteriaceae D-Glucose 0 0 0 0.43 0.32 0.15 0.15 L-Glucose 0 0 1.07 1.07 1.07 1.07 1.07

D-Tagatose 0 000000 Downloaded from http://meridian.allenpress.com/jfp/article-pdf/63/1/71/1669933/0362-028x-63_1_71.pdf by guest on 25 September 2021

in order to sustain themselves. Yet, the Enterobacteria- ACKNOWLEDGMENTS ceae level remained unchanged at both psychrotrophic and The authors thank Mr. Daniel Prefontaine, Mrs. Heather Silcox, and mesophilic temperatures for all sugars examined during Mr. Trevor Stonstelie of the Saskatchewan Food Product Innovation Pro- the course of this study. This suggests that L-glucose and gram at the University of Saskatchewan for their technical assistance. The D-tagatose do not promote a favorable shift in the Entero- authors appreciate the generous donation of Biospherics, Inc. for sugars bacteriaceae population that may be useful in preventing used in this study and are grateful to the Saskatchewan Agriculture De- foodborne illness by gram-negative pathogenic bacteria. velopment Fund for ®nancial support. Perhaps the packaging material (polyethylene/polyamide; REFERENCES ®lm thickness, 3.1 mil Ϯ 0.2; oxygen permeation, 54 cc/ m2/24 h; water vapor transmission, 9.3 g/m2/24 h) and 1. Anonymous. 1998. The Canadian Poultry Industry. Personal com- environment of the ham product were unsuited for these munication. Ͼ 2. DeLoach, J. R., B. A. Oyofo, D. E. Corrier, L. F. Kubena, R. L. bacteria. No signi®cant (P 0.20) synergistic effects were Ziprin, and J. O. Norman. 1990. Reduction of Salmonella typhimu- observed between sugar type and storage temperature. rium concentration in broiler chickens by milk or whey. Avian Dis. In summary, these results suggest that the application 34:389±392. of D-tagatose can deter the development of lactic acid bac- 3. Hedrick, H. B., E. D. Elton, J. C. Forrest, M. D. Judge, and R. A. teria that cause spoilage. Research will continue to deter- Merkel. 1994. Principles of meat science, 3rd ed. Kendall/Hunt Pub- lishing Company, Dubuque, Iowa. mine whether these unique sugars can maintain/improve 4. Helrich, K. (ed.). 1990. Of®cial methods of analysis of the associ- shelf life with respect to sensory qualities such as ap- ation of of®cial analytical chemists, 15th ed. Association of Of®cial pearance, ¯avor, and texture. Future experiments may in- Analytical Chemists, Inc., Arlington, Va. volve the application of these alternative sugars to fer- 5. ICMSF (International Commission on Microbiological Speci®cation mented meat products to favor the growth of desirable for Foods). 1980. Microbial ecology of foods: food commodities, vol. 2, p. 333±407. Academic Press, Inc., London, UK. bacteria. Preliminary research has shown that a variety of 6. Ingraham, J. L., and G. F. Bailey. 1959. Comparative study of effect starter cultures for fermented meat products have the abil- of temperature on metabolism of psychrophilic and mesophilic bac- ity to utilize L-glucose and D-tagatose. Research is cur- teria. J. Bacteriol. 77:609±613. rently underway to examine if a probiotic system could 7. Jay, J. M. 1992. Spoilage of fresh and processed meats, poultry and be incorporated into a fermented meat product that pro- seafood, p. 199±233. In Modern food microbiology, 4th ed. Chap- man & Hall, New York. motes a microecological shift for starter culture bacteria 8. Lawrie, R. A. 1991. Chapter 4. Chemical and biochemical consti- and could possibly eliminate the presence of unfavorable tution of muscle, p. 48±81. In Meat science, 5th ed. Pergamon Press, bacteria in the meat. Oxford, UK.

TABLE 6. Least-square means of growth rates of microbial populations in a chopped and formed ham product with either D-glucose, L-glucose or D-tagatose in the formulation (rate: log([log CFU]/day)) Aerobic plate counta Lactic acid bacteria counta Enterobacteriaceae counta

Monosaccharide 10ЊC22ЊC 10ЊC22ЊC 10ЊC22ЊC

D-Glucose 0.1069 A 0.5390 A 0.1157 A 0.4742 A 0.0083 A 0.0117 A L-Glucose 0.0369 A 0.4570 A 0.0526 A 0.5590 A 0.0094 A 0.0093 A D-Tagatose 0.0088 B 0.1895 B 0.0058 B 0.1909 B 0.0085 A 0.0083 A a Least square means within columns for each temperature having different letters differ signi®cantly (P Ͻ 0.05). J. Food Prot., Vol. 63, No. 1 GLUCOSE AND TAGATOSE EFFECTS ON BACTERIAL GROWTH 77

9. Levin, G. V., L. R. Zehner, J. P. Saunders, and J. R. Beadle. 1995. Ziprin, and H. H. Mollenhauer. 1989. Effect of carbohydrates on Sugar substitutes: their energy values, bulk characteristics, and Salmonella typhimurium colonization in broiler chickens. Avian Dis. potential health bene®ts. Am. J. Clin. Nutr. 62(Suppl.):1161S± 33:531±534. 1168S. 13. SAS Institute. 1988. SAS/STAT. User's guide, release 6.03 edition. 10. Livesey, G., and J. C. Brown. 1996. D-Tagatose is a bulk sweetener SAS Institute Inc., Cary, N.C. with zero energy determined in rats. J. Nutr. 126:1601±1609. 14. Von Holy, A., and W. H. Holzapfel. 1989. Spoilage of vacuum pack- 11. Londer, R. 1988. 2001 agriculture: meals for the millennium. Dis- aged processed meats by lactic acid bacteria and economic conse- cover 9(11):60±63. quences, p. 185±190. Proc. World Assoc. Vet. Hyg. Symp. 12. Oyofo, B. A., J. R. DeLoach, D. E. Corrier, J. O. Norman, R. L. Downloaded from http://meridian.allenpress.com/jfp/article-pdf/63/1/71/1669933/0362-028x-63_1_71.pdf by guest on 25 September 2021