Effect Of Microbial Contanmination Conditions Of Slaughtering And Splitting Process On Microbioal Diversity Of Chilled Vacuum-packaged Beef Duirng Storage、，\-./J>

The level of contaminated microorganism in three big beef slaughter plants and differentslaughter process were investigated, including all the critical control points. Also loins fromdifferent plants were sampled, and stored at2℃under vacuum-packaging. A combination ofculture-dependent and culture-independent methods (PCR-DGGE fingerprinting technology)were carried out to investigate the similarity between environment samples and meat samples.The aim was to provide a basic theory and technique for the inspection of quality and safetyduring the slaughter, transportation and preservation of chilled beef. The results were asfollows:1、The level of contaminated microorganism in three big beef slaughter plants and differentslaughter process were investigated. The result showed that the level of contaminatedmicroorganism had the difference in different slaughter plants and different process. And TPC(total plate counts) of some surfaces exceeded104CFU/g, which were unacceptable accordingto the international standards, which would influence the initial microbial load and shorten theshelf-life.2、The microbial similarity and diversity of different slaughter and split steps wereinvestigated. The results showed that the microbial similarity between each plant and eachstep was significantly different. The number of the microorganism on the surface of beefcarcasses between the steps had significant correlation. The eviscerating step and workers’hands during splitting process and trimming steps during splitting process had significantcorrelation with the microbial diversity during the final storage, which could be considered asthe main contamination resources of the dominant spoilage bacteria.3、During chilled storage, the load of lactic acid bateria had quickly became the dominantcommunity, reaching108CFU/g, which greatly suppressed the growth of Pseudomonas,Brochothrix and Enerobacteriacea.4、The microbial diversity of meat samples from different plants became lower with thestorage prolonged, while the similarity increased.5、The dominant strains which do the main contribution to the spoilage of chilledvacuum-packaged beef detected by DGGE fingerprinting technology included: Lactobacillussp., Carnobacterium sp., Psychrobacter sp., Brochothrix thermosphacta, Leuconostoc gasicomitatum. And Lactobacillus sakei was the main dominant bateria.