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 Senftenberg, Salmonella Typhimurium, Salmonella Heidelberg, Salmonella Mission, Salmonella Montevideo, Salmonella California, and Listeria innocua. The initial inoculation of bacteria was approximately 10(7) log10 CFU/g. The inoculated patties were processed in a pilot-scale air convection oven at an air temperature of 177 degrees C, an air velocity of 9.9 m3/min, and a low (a wet bulb temperature of 48 degrees C) or high (a wet bulb temperature of 93 degrees C) humidity condition. The patties were processed to a final center temperature of 65 to 75 degrees C. 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 CO2 at refrigerated (4 degrees C) or thermally abused (8 to 15 degrees C) temperatures. Storage temperature, time, and gas environment affected the bacteria growth. Higher storage temperature and longer storage time correlated to an increased growth of bacteria in the cooked chicken patties. Less Salmonella (2 logs) and Listeria (0.5 to 1 log) cells were obtained in the patties stored under vacuum than in air. Storing the patties in 30% CO2 reduced the growth of Salmonella more than 2 log10 CFU/g. At a CO2 level of 15%, 1 log10 CFU/g of reduction was obtained for Listeria in cooked chicken patties.
Murphy
R Y
RY
Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville 72701, USA. rymurph@comp.uark.edu
Johnson
E R
ER
Marcy
J A
JA
Johnson
M G
MG
D000332:Aerobiosis; D000818:Animals; D002245:Carbon Dioxide; D002645:Chickens; D015169:Colony Count, Microbial; D005511:Food Handling; D006813:Humidity; D008087:Listeria / Q000254:growth & development*; D008460:Meat / Q000382:microbiology*; D012475:Salmonella / Q000254:growth & development*; D013696:Temperature; D013997:Time Factors; D014618:Vacuum
D002245:Carbon Dioxide