ABSTRACT
The ability of Yersinia enterocolitica 0:3 to grow and survive during the manufacture of fermented sausages made with 0, 50, 80, 100, and 120 mg/kg added sodium nitrite and three different commercial starter cultures was determined. The sausage mass was inoculated to contain 1.7 × 105 of Y. enterocolitica per g. Yersinia was not detected after 28 d in sausages made with 80, 100, or 120 mg/kg of sodium nitrite. All sausages manufactured without or with 50 mg/kg sodium nitrite harbored Yersinia during the test period of 35 d. The highest level of Yersinia (5.9 log10 CFU/g) was detected in sausages made with no sodium nitrite and with Pediococcus acidilactici ©. In sausages made with Lactobacillus pentosus (A), the level of Yersinia was less than 2.0 log10 CFU/g. In sausages made with Lactobacillus plantarum (B) and 50 mg/kg sodium nitrite, the level of Yersinia was 2.9 log10 CFU/g. The pH values made with starters A, B, and C reached the pH values of 4.9, 5.2, and 5.4, respectively.
ABSTRACT
The fate of L. monocytogenes during the fermentation of Finnish fermented sausage was examined. L. monocytogenes was able to survive during a 21 d fermentation of sausage with levels of nitrite and salt commonly used in the meat industry today (120 ppm NaNO2 and 3.0% NaCl). Initial numbers of Listeria (103 CFU/g and 105 CFU/g) decreased approximately 1 log 10 CFU/g during the manufacture. Increasing the levels of nitrite/nitrate to those used 30 years ago in meat products had a marked effect on the elimination of Listeria . The numbers of survivors in the sausages was reduced 2.0 log 10 CFU/g during the fermentation of 3 weeks with a combination of 200 ppm NaNO2 and 300 ppm KNO3. With 1000 ppm KNO3, the decrease was 3.3 log 10 CFU/g. L. monocytogenes could not be totally eliminated from highly contaminated sausage by increasing only the levels of nitrite and nitrate. Levels of these additives with best bacteriostatic effect on Listeria are no longer permitted in food.
