Investigation And Analysis Of Microorganisms In Dairy Processing Environment

In recent years, dairy safety events are often caused by microorganisms. Currently, many reports focus on spoilage bacteria in raw milk and dairy products, and are mainly limited to microbiological hazards analysis and detection on the number of microorganisms, but lack of analysis of microorganisms in the dairy processing environment. This paper studied the distribution of microorganisms in yogurt and pasteurized milk processing environment,which gave a general understanding of the microorganisms in the dairy processing environment, and proposed appropriate control measures to reduce the secondary pollution of the dairy processing environment.A dairy yogurt workshop and a low-temperature pasteurized milk workshop were tested with microbial sampling inspection.The microbial species and the distribution of the microorganisms were analyzed by molecular biology and biochemical methods. The study results are as follow:(1)The number of microorganisms in yogurt processing environment and low-temperature pasteurized milk processing environment are accordance the requirements of the Dairy Products Good Manufacturing Practice.(2) The dominant bacteria in yogurt processing environment are Staphylococcus sp, Bacillus sp, Micrococcus sp, Acinetobacter sp, psychrophilic bacteria (Pseudomonas sp, psyctrophic Bacillus), Macrococcus sp, Rhodotorula sp, Penicillium sp, which are widely present in the natural environment, and can resist to adverse environmental, so this kind bacteria are more easyily polluted.(3)Through traceability analysis of the Bacillus sp in yogurt workshop, there was cross contamination between filling and packaging buffer room, mixing room and pretreatment room, secondary packaging and products holding room. Also the corresponding cross-contamination control measures.(4) The dominant bacteria in the air of low-temperature pasteurized milk plant are Micrococcus sp, Bacillus sp, Corynebacterium sp, psychrotrophic sp, Acinetobacter sp. Results showed that the species and number of microorganisms detected in pasteurized milk workshop are both less than those done in the yogurt workshop,which because there are less low-temperature pasteurized milk processing technology, less personnel needed, and less environmental pollution.(5) The results show that the monitoring points of same processing environment contain the same dominant microorganisms, in different processes, the dominant bacteria in connected workshops are basically the same. That points out that there is cross pollution phenomena between the different segments.Finally, the distribution of microbial contamination in the processing environment,was given, from people, machines, materials, environment four aspect, different control measures were come up.