88D-17 |
Optimizing combinations of chemical and biological microbial inhibitors in inhibiting psychrotrophic spoilage organisms in raw chicken meat |
E. Y. PALANG, Food Science, University of Georgia, 1020 Food Science Building, Athens, GA 30605 and R. T. Toledo. Although organic acids have been used to extend shelf-life of raw poultry, their effectiveness levels are at a point where altered product flavor is detectable by consumers. Action of these acids is also selective and under certain conditions, total aerobic plate counts are not altered over untreated controls. Buffered acids in conjunction with other agents have potential to be more practical to use due to synergy thereby, reducing effective levels of use. We investigated capability of sodium lactate, sodium citrate, sodium diacetate and two commercial bacteriocin containing dairy derived preparations alone or in combination at different levels on growth inhibition of psychrotrophic and mesophilic bacteria extracted from raw poultry meat. Plate count agar containing the inhibitors at 0, 1.5, and 3% were prepared and pH adjusted to 4.5, 5.0, and 5.5 using citric acid. Experimental design was a 3x3x4 factorial replicated 3 times. Inocula from a raw chicken leg quarter stomached with 100 mL 0.1% peptone buffer and 10% Tween-80. Drop plate method was used and counted the adequately developed CFU. The plates were incubated at 7°C for psychrophiles and at 37°C for mesophiles. Psychrotrophic bacteria were found to be more resistant than mesophilic bacteria to the inhibitors used. Sodium diacetate effectively inhibited microbial growth at all pH levels and concentrations. Log reduction in count of psychrotrophic microorganisms was up to 4 log cycles less than the controls. The other inhibitors reduced cfu's by 2 to 3 log compared to controls but only at the 3% concentration and at pH 4.5 to 5. At 1.5% concentration, log reductions were observed only when the pH was 4.5. Tests run with marinated poultry indicated a shelf-life extension with combinations of sodium citrate (pH 5.0) at 0.5% and sodium diacetate at 0.05% level.
Session 88D, Food Microbiology: General
|