Infektionserreger in Rohwursterzeugnissen: Wirkung von Nitritpökelsalz auf grampositive Erreger in Rohwurst

Food borne infections are a health risk for the consumers of contaminated foods. The raw material (pork or beef) for sausage production can be contaminated with various pathogenic bacteria. Gramnegative enteric bacteria as well as gram positive bacteria can be found in the raw material. The addition of nitrite should result in a growth inhibition of pathogenic bacteria. However, well-founded scientific data concerning the mode of impact of nitrite on relevant food borne gram positive bacteria like L monocytogenes, C. perfringens and S. aureus are not yet available. The objectives of this study were 1. to investigate the actual impart of nitrite on various gram positive pathogens and 2. to analyze multifactorial aspects like a_w-value, pH, and temperature on the effertiveness of nitrite against L. monocytogenes EGDe. The impact of nitrite (0, 50,100 or 150 mg sodium nitrite/kg) on the survival of the respective pathogen was investigated in short-, rapid-, long- and mouldripened raw sausage using challenge tests. The results indicate a variation in effects concerning the different bacterial species and the different produrts. Nevertheless, general recommendations can be given: For microbiological stabilisation the addition of at least 100 mg/kg sodium nitrite for raw sausage is suggested. Only the fermentation of rapid-ripened raw sausages could be done without addition of nitrite. Furthermore, the impact of nitrite on growth of L monocytogenes EGDe was analysed in combination with parameters relevant for raw sausage fermentation hke pH-value, NaCl-concentration, oxygen availability and temperature in a high throughput approach. The strongest inhibitory effert of nitrite on the growth of L. monocytogenes could be observed in combination with a low pH.