Salmonella survival after exposure to heat in a model meat juice system

The effect of heat against eleven Salmonella strains in model meat juices was examined. Juices from beef, lamb and goat were made from either the fatty layer (FL), muscle (M) or a mixture of both (FLM). The pH of each FLM sample was altered to match the pH of PBS and vice versa to determine the pH effect on the survival of Salmonella against the effect of heat. Salmonella were exposed to either gradual heating to 70 degrees C in FLM, M and FL or heat shock at 70 degrees C for 5 min in FLM. Fat, fatty acid profile and iron content of the juices were determined. Gradual heat treatment significantly (p < 0.05) reduced Salmonella as compared to the untreated controls (similar to 1.92-7.61 log CFU ml(-1)) while heat shock significantly (p <= 0.05) reduced Salmonella as compared to the untreated controls (similar to 5.80-7.36 log CFU ml(-1)). Survival of Salmonella was higher in lamb juices than other juices. The fat content in lamb FL (3.25%) was significantly higher (p <= 0.05) than beef (1.30%) and goat FL (1.42%). Iron content in lamb FLM (similar to 127 mg kg(-1)) was significantly (p <= 0.05) lower than beef (similar to 233 mg kg(-1)) and goat FLM (similar to 210 mg kg(-1)). The omega 6 and linoleic acid content in goat FLM (similar to 36.0% and similar to 34.4%) was significantly higher (p <= 0.05) than beef (similar to 29.1% and similar to 27.1%). Fat, fatty acids and iron may differentially protect Salmonella against the effect of heat in these juices.