Purpose: This study compared the survival rates of Salmonella in raw chicken juice on kitchen surfaces and food packages at room temperature and refrigerated conditions.
Methods: Cultures of Salmonella Typhimurium were inoculated in raw meat juice and spread on the surfaces of kitchen countertops, refrigerator shelves, cereal box, potato chip bag, bread bag, and milk carton that were kept at room or refrigerated temperature. The numbers of viable Salmonella were continuously monitored by enumeration on XLT-4 selective agar. The experiments were repeated and all samples were replicated.
Results: The results showed a steady decline in viable rates of Salmonella at both conditions, although slower in refrigerator. Regression analyses were used to predict the decline rate in each of the conditions. On the surfaces of countertop, chip bag and cereal box at room temperature, numbers of Salmonella reduced to one hundredth of the initial levels in 16.6, 2.8 and 2.0 hours, respectively. On the surface of hands, it only took 10.1 minutes to decease to that level. In contrast, the rates of decline were much slower on the surfaces of refrigerator shelves, bread bag and milk carton in the refrigerator where it took 222.7, 43.5 and 23.7 hours, respectively, to achieve the same level of reduction.
Significance: Because Salmonella can survive days in refrigerated conditions, risk of cross-contamination to other foods is higher in the refrigerator than at the room temperature. Precautions are needed to prevent cross contamination when handling and storing raw poultry products in the refrigerator.