Growth potential of exponential- and stationary-phase Salmonella Typhimurium during sausage fermentation

Raw meat for sausage production can be contaminated with Salmonella. For technical reasons, meat is often frozen prior to mincing but it is unknown how growth of Salmonella in meat prior to freezing affects its growth potential during sausage fermentation. We investigated survival of exponential- and stationary-phase Salmonella Typhimurium (DT12 and DTU292) during freezing at -18°C and their subsequent growth potential during 72h sausage fermentation at 25°C. After 0, 7 and >35d of frozen storage, sausage batters were prepared with NaCl (3%) and NaNO2 (0, 100ppm) and fermented with and without starter culture. With no starter culture, both strains grew in both growth phases. In general, a functional starter culture abolished S. Typhimurium growth independent of growth phase and we concluded that ensuring correct fermentation is important for sausage safety. However, despite efficient fermentation, sporadic growth of exponential-phase cells of S. Typhimurium was observed drawing attention to the handling and storage of sausage meat.