Browsing by Author "Tyler, Carla Gutierrez"
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- Acceptability and Shelf-Life of Fresh and Pasteurized Crab Meat Stored Under Different Environmental ConditionsTyler, Carla Gutierrez (Virginia Tech, 2009-02-02)Crab meat is important to the economy of coastal Virginia. The objectives of this study were to complete a shelf-life study on two different packaging styles of fresh crab meat and to test the inhibition capabilities of Carnobacterium piscicola against the pathogen, Listeria monocytogenes. In a shelf-life study, a 12 ounce food grade polyethylene traditional snap-lid container of fresh crab meat was compared to an 8 ounce SimpleStep® trays with Cryovac™ film of equally fresh crab meat sealed with 10,000 cc/m2/24hr oxygen transmission rate (OTR) film. Eleven g samples were used for the microbial shelf-life study conducted at 4°C for 12 days. Aerobic plate counts of crab meat indicated microbial growth from the SimpleStep® trays with Cryovac™ film in 10,000 cc/m2/24hr OTR versus the polyethylene snap-lid was not significant (P>0.05). In objective two, 25 g samples of fresh and pasteurized blue crab (Callinectes sapidus) meat were inoculated with 0.1ml of each, C. piscicola and L. monocytogenes. Three different concentrations of the inoculation levels were studied on select days at both 4°C and 10°C. Microbial spoilage was defined as 107 CFU/g. In fresh crab meat, at both 4°C and 10°C, crab meat spoilage occurred at 7 days or less. In the pasteurized crab meat, at 4°C and 10°C, spoilage did not occur prior to 26 days, and studies were terminated at 28 days of storage. The growth of the two organisms in fresh crab meat was found to be significant for the differing concentration levels and sampling days (P<0.05). The growth of the two organisms in pasteurized crab meat was significant for different concentration levels, sampling days and temperature (P<0.05). In both fresh and pasteurized crab meat, regardless of the inoculation ratios, the L. monocytogenes and C.piscicola followed similar growth trends, but L. monocytogenes was higher in the 2:2 CFU/g concentration and lower at the 6:2 CFU/g concentration level. Although C. piscicola did not completely inhibit L. monocytogenes growth at any concentration ratio, some inhibition was observed.
- Inhibition of Listeria monocytogenes by Carnobacterium piscicola in Fresh and Pasteurized Crab MeatTyler, Carla Gutierrez; Jahncke, Michael; Sumner, Susan S.; Hackney, Cameron Raj; Boyer, Renee R.; Wang, Hengjian; Rippen, Thomas E. (2012)The ability of Carnobacterium piscicola to inhibit Listeria monocytogenes at different concentration levels, storage times and temperatures was examined. Twenty-five g samples of fresh and previously pasteurized blue crab meat were placed into separate sterile 59 ml soufflé cups, inoculated with 0.1 ml C. piscicola at three different concentration levels (2, 4 and 6 log CFU/g) and 0.1 ml (log 2.0 CFU) of L. monocytogenes (ratios of 1:1, 2:1 and 3:1 of C. piscicola to L. monocytogenes). Fresh crab meat and previously pasteurized crab meat was stored at 4°C or 10°C and sampled until aerobic plate count reached ≥ 7 log CFU/g, which was considered spoilage. At each sampling time, crab meat inoculated with both organisms was plated on modified Lactobacillius deMan Rogosa Sharpe (pH 7) and modified oxford agar (MOX). Uninoculated crab meat was plated on trypticase soy agar and meat inoculated with only L. monocytogenes was plated on MOX. In both fresh and pasteurized crab meat, regardless of the inoculation levels, L. monocytogenes and C. piscicola followed similar growth trends. C. piscicola reduced growth of L. monocytogenes in pasteurized crab meat after 14 day at 4°C and 10 day at 10°C (P < 0.05).
- Role of package type on shelf-life of fresh crab meatTyler, Carla Gutierrez; Jahncke, Michael L.; Sumner, Susan S.; Boyer, Renee R.; Hackney, Cameron Raj; Rippen, Thomas E. (Food Protection Trends, 2010)Microbiological quality of fresh (not pasteurized) crab meat stored at 4°C in a 340 g (12 oz) food grade polyethylene traditional snap-lid container and equally fresh crab meat stored at 4°C in a 227 g (8 oz) SimpleStep® tray sealed with Cryovac™ film (oxygen transmission rate of 10,000 cc/m2/24 h) was evaluated over a 12-day period. Aerobic plate counts were conducted on storage days 0, 4, 6, 8, 10 and 12. Anaerobic plate counts were conducted on storage days 0, 5 and 12. Aerobic plate counts of crab meat from the two containers did not differ (P > 0.05). Analysis of anaerobic microbial growth indicates that sampling days were significant (P < 0.05), but container type or style was not significant (P > 0.05). Oxygen and CO2 in the package headspace was significantly different between container types (P < 0.05). Gas concentration between sampling days was not significant (P > 0.05). Results of this study demonstrate that there were no significant differences in refrigerated shelf life of crab meat packaged in SimpleStep® trays with Cryovac™ film versus the traditional polyethylene snap-lid container packaging (P > 0.05).