The Change Of Microorganism And Physicochemical Characteristics In Chilled Rabbit Meat During Storage And Their Relationships

Rabbit meat is a kind of healthy meat that has high nutrition, so it is welcomed by more and more consumers. Chilled rabbit meat, as a high-quality product, is fresh, delicious, nutritional and safe, which is bound to be the future development trend of rabbit meat and its products. At present, there are few researches about chilled rabbit meat, and the development of chilled rabbit meat market is relatively slow. The key factor is the short shelf life that leads to unfavorable sales. Therefore, this study aimed to freshly slaughtered rabbit, selected several domestic and international packaging methods including tray packaging, vacuum packaging and modified atmosphere packaging, and set three temperature gradients. The objective of the experiment is to study the effect of different packaging methods and different temperatures to the shelf life and the quality of chilled rabbit meat, and then analyze the relationship between microorganism and physicochemical characteristics in chilled rabbit meat during storage, explore the relationship between the color and quality characteristics, and grasp the variation pattern of chilled rabbit meat during storage. Then provide database for further study about mechanism of a variety of physiological and chemical changes in rabbit meat, and guide industrial production technically. The experimental conclusions are as follows:1. Total plate count, TVB-N value and TBARS value of chilled rabbit in tray packaging, vacuum packaging and modified atmosphere packaging were proportional to the storage time. With the increase of storage time, microorganisms in the surface of rabbit meat increased, protein degraded, lipid oxidized and the quality declined.2. The difference of color was mainly affected by different packaging methods; small temperature differences had little effect on color. With the increase of storage time, the color of the chilled rabbit meat changed. The color change of the chilled rabbit meat in vacuum packaging was significantly greater than the other two kinds of packaging. L* and a* of the chilled rabbit meat in tray packaging and modified atmosphere packaging declined, b* slightly decreased; the color of the chilled rabbit meat in vacuum packaging changed, especially a* declined significantly, and negative value appeared after a week, it seriously affected the sensory quality of meat.3. Different packaging methods had significant effect on the shelf life of rabbit meat. In the same temperature condition, the shelf lifes of rabbit meat were:modified atmosphere packaging> vacuum packaging> tray packaging.4. Different temperatures had significant effect on the shelf life of rabbit meat. According to TVB-N and microbial indicators, low temperature was very important to extend the shelf life of chilled rabbit meat.5. During the shelf life of chilled rabbit meat, there were significant correlations among different indexes, indicating that lipid oxidation, protein degradation, proliferation of bacteria and color change were interrelated.6. The pathogen, including Staphylococcus aureus, Salmonella, Shigella and Listeria monocytogenes, in chilled rabbit meat in tray packaging, vacuum packaging and modified atmosphere packaging could not be detected during their shelf life,.Tray packaging, as an aerobic packaging method, is widely used because of its low price, convenience and practicality; however, the experiment proved that the rabbit meat in tray packaging could not maintain flesh in the late storage period and corrupted rapidly. Therefore, it could only be used in short-term sales (less than a week).Vacuum packaging inhibited the growth of aerobic spoilage bacteria due to the lack of oxygen, but could not inhibit the growth of Lactobacillus, which soon became the dominant strain in chilled rabbit meat during storage. Lactobacillus broke down sugar to produce lactic acid, decomposed protein slowly and did not produce toxins, so the corruption caused by Lactobacillus was slow and mild. However, the negative pressure in the vacuum-packed bags caused severe dehydration in chilled rabbit meat and the lack of oxygen made the flesh meat have a bad color, all of them bring certain restrictions to the application of vacuum packaging.Modified atmosphere packaging effectively inhibited the metabolism and microbial activity of chilled rabbit meat. To a certain extent, it maintained the color of the rabbit. The total plate count, TVB-N and TBARS of chilled rabbit meat in modified atmosphere packaging were relatively slow during storage. It is one of the best ways to extend the shelf life of rabbit meat. However, the split rabbit meat could not be fixed in MAP bag and the juice stick bags, affecting the appearance of the product.Comprehensive comparison:the shelf life of rabbit meat in different packaging methods and different temperatures were as follows:Modified atmosphere packaging(-1～0℃)> Modified atmosphere packaging(3～4℃)> Modified atmosphere packaging(6～7℃)> Vacuum packaging (-1～0℃)> Vacuum packaging (3～4℃)> Vacuum packaging (6～7℃)=≈Tray packaging(-1～0℃)≥Tray packaging(3～4℃)≥Tray packaging(6～7℃).