Research on pollution sources of spoilage bacteria in pasteurized milk by PCR-DGGE

PCR-DGGE technology was applied to analyze the differences and dynamic changes of microbial community of pasteurized milk from key control points of raw milk to pasteurization and filling process. The results showed that the points proned to be contaminated were milk making, processing pipeline after pasteurization and packaging. Lactococcus lactis subsp. and Lactobacillus sp. were easy carried by raw milk.Streptococcus agalactiae was polluted at milk making. Brochothrix thermosphacta,Enterococcus casseliflavus,Lactobacillus helveticus and 2 strains of uncultured Pseudomonas sp. might be polluted at processing pipeline after pasteurization. Carnobacterium sp. and Carnobacterium maltaromaticum may be polluted at milk making,processing pipeline after pasteurization and packaging.