Study Of The Bioprotective Cultures On Meat Quality And Spoilage Bacteria On Vacuum Packaged Sliced Beef

The chilled beef have been the main consumed form. But the bacteria can easily growbecause of the nutrition and the structure of the beef. Especially the cold chain system is notperfect, the spoilage due to the growth of the bacteria became the main factor to effect theshelf-life. It was essential to inhibit the spoilage bacteria based on promise of the beef qualityand to extend the shelf life. Nowadays, the study based on the control of the bacteria andcomprehensive preserving technique was hot in the world. The purpose of the study was tostudy the main spoilage bacteria and its rule of the dynamic growth using the modernbiotechnology in combination of the traditional culture methods. This study evaluated theLactobacillus sakei B-2and Lactobacillus curvatus B-LC-48as the bioprotective cultures toensure the effect on beef quality and the extension shelf life stored at different temperature. Inthe present study, the Longissimus dorsi was brought directly from the factory, then vacuumpackaged, examined the pH value, color, water holding capacity, total volatile basic nitrogen(TVBN) and the microbiology such as total viable counts (TVC), lactic acid bacteria (LAB),Enterbacteriaceae, the Pseudomonas spp. Brochthrix thermosphacta at the internal of0、7、14、21、28、38days at4℃and0、4、8、12、16、21days. Besides, the PCR-DGGE technologywas researched to describe the dynamic change and the interaction between the bioprotectivecultures and the spoilage bacteria.The main results were as follows:1.The inoculation of the Lactobacillus sakei B-2was7.48log10cfu/g, the inoculation of theLactobacillus curvatus B-LC-48was7.31log10cfu/g at4℃. The shelf life of the controlsamples28days based on the TVBN value while the two treatment samples was at least38days. The two culture samples extend the shelf life at least10days.2.The inoculation of the Lactobacillus sakei B-2was7.71log10cfu/g, the inoculation of theLactobacillus curvatus B-LC-48was7.05log10cfu/g at8℃. The shelf life of the controlsamples16days based on the TVBN value while the two treatment samples was at least21days. The two culture samples extend the shelf life at least5days.3. The effect of meat quality on the control and treatment samples presented the same trend:the two treatments decreased the pH value, improved L*value while no effect on a*. Andeffect of the water holding capacity was little. Besides, the same effect on the TVBN value about the two treatments. It can be concluded that the two bioprotective cultures have noeffect at different temperature.4. The inhibition of the spoilage bacteria was different at different temperatures. Through thetraditional cultural methods, we can concluded that the inhibition of Lactobacillus sakei B-2to the Enterbacteriaceae, the Pseudomonas spp. Brochthrix thermosphacta was stronger thanthe Lactobacillus curvatus B-LC-48which had a few inhibition to the same bacteria. However,the suppression was weaker when stored at4℃. It can be concluded that the temperature canaffect the capacity of the suppression of the spoilage bacteria and different bioprotectivecultures had different action. On the whole, the role of the Lactobacillus sakei B-2had aadvantage on the Lactobacillus curvatus B-LC-48.5. We can get the dynamic change of the microbiology at different temperature using thePCR-DGGE technology. From the DGGE profile of4℃, the inhibition of the two cultureswas almost same, both inhibit the growth of Enterbacteraceae, Pseudomonas fragi,Brochothrix thermosphacta, Pseudomonas putida, uncultured bacteria, but had little effect onthe Lactobacillus graminis, Leuconostoc mesenteroides, uncultured Lactobacillus,Lactobacillus fuchuensis, Leuconostoc carnosum.6. There was eleven bands at8℃which was fewer than the number of4℃DGGEprofiles(total16bands). The application of the bioprotection can decrease the microbiologicaldiversity. At the same time, the two cultures inhibited the Pseudomonas fraqi, Brochothrixthermosphacta, Uncultured bacteria, Carnobacterium sp., Enterbacteria bacterium、Lister sp.