Survival and growth of Salmonella and Listeria in the chicken breast patties subjected to time and temperature abuse under varying conditions

Chicken breast patties were inoculated with a mixture of Salmonella Senften berg, Salmonella Typhimurium, Salmonella Heidelberg, Salmonella Mission, Sa lmonella Montevideo, Salmonella California, and Listeria innocua. The initi al inoculation of bacteria was approximately 10(7) log(10) CFU/g. The inocu lated patties were processed in a pilot-scale air convection oven at an air temperature of 177 degreesC, an air velocity of 9.9 m(3)/min, and a low (a wet bulb temperature of 48 degreesC) or high (a wet bulb temperature of 93 degreesC) humidity condition. The patties were processed to a final center temperature of 65 to 75 degreesC. The survivors of Salmonella and Listeria in the processed patties were evaluated. Processing humidity affected the survivors of bacteria. More survivors of Salmonella and Listeria (>2 logs) were obtained for the patties cooked at low humidity than at high humidity. After thermal processing, the patties were stored under air, vacuum, or CO 2 at refrigerated (4 degreesC) or thermally abused (8 to 15 degreesC) tempe ratures. Storage temperature, time, and gas environment affected the bacter ia growth. Higher storage temperature and longer storage time correlated to an increased growth of bacteria in the cooked chicken patties. Less Salmon ella (2 logs) and Listeria (0.5 to 1 log) cells were obtained in the pattie s stored under vacuum than in air. Storing the patties in 30% CO2 reduced t he growth of Salmonella more than 2 log(10) CFU/g. At a CO2 level of 15%, 1 log(10) CFU/g of reduction was obtained for Listeria in cooked chicken pat ties.