Effects of NaCl, sucrose, and water content on the survival of Salmonella typhimurium on irradiated pork and chicken

We investigated the effects of water content, activity, sodium chloride (NaCl) and sucrose contents on the survival of Salmonella typhimurium ATCC 14028 in irradiated mechanically deboned chicken meat (MDCM) and ground pork loin. The effects of NaCl and sucrose concentration were investigated by adding various amounts to MDCM or ground pork loin, or by rehydrating freeze-dried ground pork loin with NaCl solutions with various degrees of saturation. The effects of water content were investigated by rehydrating freeze-dried ground pork loin with different quantities of water. Inoculated samples were irradiated at 5 degrees C in vacuo to various doses up to 6.0 kGy. Highly significant effects (p < 0.01) of water content, water activity (aw) and NaCl content, but not of sucrose content, on the survival of S. typhimurium were identified. The failure of sucrose to provide the same protection for S. typhimurium in meat against radiation argues against reduced water activity being a primary mechanism of protection. The results indicate that the survival of foodborne pathogens on irradiated meats with reduced water content or increased NaCl levels may be greater than expected.