Abstract: Abstract: In order to explore the mechanism of lactobacillus starter inhibiting the formation of N-nitrosamines, a lactobacillus starter PRO-MIX5 (Staphylococcus xylosus + Lactobacillus brevis + Lactobacillus plantarum) was screened by preliminary experiments, which was cultured in Chyme medium and MRS medium respectively. Through different treatments and experiments in vitro simulation system, the effects of degradation of nitrite to inhibition of N-nitrosamine formation were screened step by step. The effects of metabolites, intracellular enzymes and bacteria were excluded, and the mechanism of inhibition of N-nitrosamine formation by lactic acid bacteria was obtained. The culture of lactic acid bacteria was further screened. The effects of nutrient methods and the amount of effective substances on the inhibition of N-nitrosamines were studied. Finally, the effective substances were applied to the production of sausage and bacon in the proportion of 0.05%, 0.25% and 0.5% wet weight respectively to verify their inhibition on the formation of N-nitrosamines in products. The results showed that PRO-MIX5 inhibited the formation of N-nitrosamines mainly by its bacterial debris. The inhibition effect of PRO-MIX5 on the formation of N-nitrosamines was better by using MRS broth medium containing 9 N-nitrosamines with 0.04 μg/mL concentration. It was applied in the three proportions of sausage and bacon. The inhibition rates of 9 N-nitrosamines were 41.05% and 13.83% respectively, and the application effect was good.

Key words: Keywords: Lactic acid bacteria, N-nitrosamine, nitrite, N-dimethylnitrosamine, sausage, Bacon