Study On The Microbial Control Technology Of Raw Milk

As the basic material of milk manufacture, the quality control of raw milk is a committed step. However, these nutrients are sufficiently hospitable for microbe’s growth and reproduction; therefore, the study on microbe in raw milk is meaningful both in theory and practical aspect and may be helpful to control the milk quality. In this paper, the distribution and source of microbial contaminants in raw milk were studied, and control measures to reduce the number of microorganisms in milk also be proposed.For the study of microbial contaminants source of raw milk, microbiology pollution of the raw milk, surface of cow body, milking equipments, water resource, soil environment and feed, etc. were analyzed and investigated. The samples were collected from three different scales of farms in Beijing and its surrounding areas between2011and2012. Aerobic bacterial count, Psychrophiles count and Bacillus count etc. in raw milk were detected as main parameters. And the target bacteria from raw milk samples were determined.The results are as follow:(1) Results of the three different scales of farms showed that the number of microorganisms of different sampling points varies a lot from dairy farm to dairy cooperatives.(2) According to morphology characteristics, phenotypic analysis and the text of carbohydrate fermentation,36species strains were identified, among which12matches Staphylococcus spp,14matches Psychrohpile,10matches Bacillus spp, Staphylococcus aureus was the main pathogenic bacteria of the raw milk and Psychrophilic, Bacillus spp were closely to the quality of milk products.(3) Analyzed gene of these three bacteria from the raw milk samples and other source samples by using16S rRNA of molecular methods for building phylogenetic tree, moreover, ascertain the main source of these bacteria in raw milk.(4) Through microbial source tracking, it was found that the harmful microorganism was mostly from production environment. For example, lactiferous pipeline、measuring bottle、milk-storage tank, milk vehicle and other links closely contacted the milk have big effect on the total aerobic bacterial count.Finally, according to HACCP principle and the result of phylogenetic tree,5CCPs should be controlled in raw milk production, which include raise of dairy cows, cleaning of breast, milk storage and transport, and cleaning equipment.