Study On Preservation Of Fresh Prepared Meat In High Oxygen Modified Atmosphere Packaging And Chandes In The Bacterial Communities

Prepared meat was popular among consumers because of its convenience, nutrition and safety.But prepared meat still occupied a small proportion of meat products in China as its short shelf life. Meat corruption caused mainly due to microbial contamination,the meat products’shelf life depended on the number and type of contaminating microorganisms.So understanding the diversity of microbial contamination in meat products to determine the dominant spoilage microorganisms was important to select the correct packaging preservation measures and improve the safety of the meat.This paper studied the effect of conditioning ingredients on the prepared meat of modified atmosphere packaging, revealed advantage corruption species of chilled prepared meat in the storage process by PCR-DGGE technique and explored the variation of main spoilage bacteria in further. The detailed contents comprised the following three aspects:1. Study on the preservation of fresh prepared meat in high oxygen modified atmosphere packagingWith fresh pork as raw materials, taking salt, the composite spices, cooking wine content as the orthogonal experiment factors to explore the quality and sanitation index change of marinated meat of modified atmosphere packaging at4℃. Results indicated that pH value and bacteria count significantly decreased(p<0.05) compared with fresh meat, the two indexes gradually increased in the storage process. After5days it reached to the second-grade standard of the fresh pork. Red value gradually decreased, shear force value showed an upward trend,but they were still acceptable in the shelf period. There was significant interaction among salt content, compound spices and wine content on the bacteria count(P<0.01), According to comprehensive regression analysis of pH value,shear force value and bacteria count and optimizing orthogonal, the best combination was:salt 1.8%, spicesl.5%, wine7%.2. Rapid identification of molecular of the predominate spoilage bacteria on fresh prepared meat in high oxygen modified atmosphere packaging during storage periodThe predominate spoilage bacteria of the fresh prepared meat in modified atmosphere packaging during storage period was identified by PCR amplification and denaturing gradient gel electrophorsis based on16S rDNA.The products was samplied at different time during storaged at4℃. The total DNA was extracted and the V6-V8region of16S rDNA was amplified by using a universal primer. The microbial flor structure was analyzed by denaturing gradient gel electrophoresis. Sequences were aligned to16S rDNA gene fragments available from NCBI to find the closest known relatives to this partial16SrDNA sequences.The DGGE pattern revealed that initial microorgan-isms with a large number of contaminants were not necessarily dominant spoilage bacteria; however, the microorganisnms that could adapt to the low-temperature developed to dominant spoilage bacteria.The results of sequencing showed that the dominant spoilage bacteria of the fresh prepared meat of modified atmosphere packaging during storage period were Pseudomonas, Brochothrix thermosphacta, Enterobacteriaceae.3. Analysis of the change of major microbia flora on fresh prepared meat in high oxygen modified atmosphere packaging during storage periodBacteria count,Enterobacteriaceae,Pseudomonas, Staphylococcus and Brochoth-rix thermosphacta were analyzed to study dynamic change of microbia flora of fresh prepared meat in modified atmosphere packaging stored at4℃,10℃and25℃. The results show that:the storage temperature had no effect on bacteria constitute, but affected microbial growth of fresh prepared meat significantly, lower temperature can inhibit the growth of microorganisms. See changes by microorganisms, bacteria count achieved106CFU/g when meat corruption appeared stored at4℃. Determining the product’s shelf life is5d from the previous indicators. The dominant microbe of fresh prepared meat was Pseudomonas, followed by Brochothrix thermosphacta. Staphylo-coccus and Enterobacteriaceae occupied a large number of bacteria count in the initial storage,but changed gently during storage period.