Study Of The Different Packaging Methods On The Quality And Spoilage Bacteria Of Chilled Beef

Bacteria can easily grow because of the nutrition and the structure of the beef.Though the growth of most bacteria in chilled meat tends to be inhibited in lower temperature,some psychrotrophic bacteria still grow well even under the chilling conditions,leading to spoilage of the chilled meat.Especially the cold chain system of China is not perfect,the spoilage due to the growth of the bacteria became the main factor to effect the shelf-life.The composition of the bacterial flora in chilled meat and the development of the spoilage flora during storage have been extensively studied.However many studies were conducted by traditional cultivation methods,which failed to reveal the true micoflora.Recently,the molecular methods based on the 16 S rDNA gene have been applied increasingly to study bacterial communities in food samples.The authors respectively discussed from the effect of modified atmosphere packaging technology on the quality of beef and microorganism problems,and the effect factors of different beef fresh-keeping,then discuss the feasibility of Denaturing gradient gel electrophoresis(Denaturing gradient gel electrophoresis,DGGE)technique for bacterial refrigerated during phase.1.The meat was stored at 4 ? for 20 days,and analyzed for the color,microbial Counts,total volatile basic nitrogen(TVB-N)and drip loss of the meat every once in a while.Using HiOx-MAP(80% O2+ 20% CO2),vacuum packing(VP)and CO-MAP(0.4% CO + 30%CO2+ 69.6% N2)can effectively inhibit the growth of microorganisms in meat,relative to the pallet packaging(CK)were able to get a better meat color,VP also represented a good performance for inhibition of the bacterial growth,but it had a lower score for drip loss,and was in a lower level of L*and a*value than those of two MAPs.HiOx-MAP Could inhibit the aerobic bacteria,and kept meat look fresh in early storage period,but drove meat darker in later days.CO-MAP could not only inhibit bacteria but also keep the L*and a*value at a high level,which indicated that CO-MAP was the best way and ideal packaging method for chilled beef.2.Samples of different processing to extract the DNA of the bacteria in the meat,PCR was carried out on the 16 S rDNA gene V3 area a DGGE analysis,combined with tapping sequencing and analysis map to get the following results: under the storage conditions of 4 ?,the belt type and belts and bright degree in map will over time and obvious changes.Pallet packaging(CK)in the process of storage,Pseudomonas grew most rapidly,and in the late storage,Brochothrix,Pseudomonas will become the main advantage of cooling beef spoilage organisms.Vacuum packaging after processing results show that the storage at the end of lactic acid bacteria are: Carnobacterium,Lactobacillus sakei,Lactobacillus became the dominant bacteria,beef vacuum packing cooling storage Lactobacillus bacteria increase gradually,in the process of storage at the end of most wine Lactobacillus;High oxygen packaging(HiOx-MAP)results show that the dominant bacteria were Carnobacterium and Brochothrix and Pseudomonas;After processing results CO-MAP show that the processing conditions of low oxygen storage late aerobic bacteria is restrained,the anaerobic bacteria mainly wine Lactobacillus,psychrophilic bacteria genera become the advantage bacterium group.Overall,use normal pallet packaging(CK)in the process of storage of samples abundance than using vacuum packaging(VP)and packaging(MAP)treatment group.Ten kinds of spoilage bacteria were found by cloning and sequencing: Bacillus?Lactococus?Carnobacterium?Acinetobacter?Brochothrix?Psychrobacter?Pseudomonas?Serratia marcescens?Lactobacillus?Listeria.