| Chilled goose is a new product based on the technology of chilled meat, which is favored by consumers because of its rich nutrition, health and processing adaptability. At present, the chilled goose industrialization production has just been started, some problems seriously restricted the development of chilled goose, for example:backward production technology, pollution of microorganism, short shelf life and so on. Therefore, it’s necessary that we regulate the production criterion of the products, draft the standard of hygienic quality, improve the controlled system of the quality safety and extend the shelf life of chilled goose.This thesis focused on the dynamic changes of micro flora of chilled goose during processing and refrigerated storage(4±1℃), and on this basis, a new and effective preservation technology which extended the shelf life of chilled goose was developed. The research provided reliable theory basis on the scale of production, improved the economic efficiency of enterprises and the processing quality.1、Analysis of bacterial contamination during the processing and refrigerated storage of chilled gooseThe effect of commercial processing on natural micro flora of chilled geese was studied. The common spoilage bacteria and pathogens microbial were taken from the surface of workers’hands, chopping boards, tools, and geese carcass in processing as well as the air and immersion chiller water as samples, and the traditional culturing and counting were operated on these samples; Meanwhile, the changes of aerobic plate count during refrigerated storage was studied. Findings indicated that the air, the immersion chiller water as well as every contact surface in processing were all potential sources of contamination and contaminated the carcasses in different extents. However, in general, the total processing decreased the level of carcass contamination, the number of bacteria recovered from processed carcasses was significantly less than that recovered from processing carcasses. Evisceration was the processing which was most contaminated, but spray rinsing and pre-chilling were effective ways of decontamination. The second immersion water and package were the main reasons of carcasses re-contaminations and directly resulted in spoilage of products after7or9days refrigerated storage.2、Study on micro floral Changes of Vacuum-packaged chilled goose during refrigerated storageThe micro floral changes in vacuum-packaged chilled goose during4℃storage was explored by PCR-denaturing gradient gel eletrophoresis (PCR-DGGE). Results indicated that Microbacterium, Acinetobacter and Aeromonas were the main initial contaminating bacteria, and always existed in the storage process; With the extension of storage time, some bacteria gradually disappeared, some bacteria such as Enterobacter, Brevibacterium and Lactococcus lactis were appeared, and Lactococcus lactis were to become the dominant bacteria of the storage end; Aeromonas were the dominant bacteria during the storage processing.3、Effects of modified atmosphere packaging with different air components on the shelf life of chilled goose under refrigerated storage(4±1℃)The effect of different modified atmosphere conditions of O2, CO2and N2on shelf life extension of chilled goose breast meat stored at4±1℃was studied. The parameters monitored were:microbiological (TVC, Pseudomonas spp. and lactic acid bacteria (LAB)) and physico-chemical (pH, TVB-N, weight loss and color). The results showed that the MAP inhibited the growth of LAB effectively, however, Pseudomonas grew rapidly and became the dominant spoilage bacteria gradually because of the presence of oxygen, the anaerobic packaging controlled the growth of microorganisms validly, delayed the process of corruption; physic-chemical indicated that the anaerobic group always maintained a fresh range throughout the refrigeration storage, the weight loss was low, the changes of color was small. Thus, we can see that anaerobic modified atmosphere packaging (70%CO2:30%N2) can significantly prolong the shelf life of chilled geese and maintain a good quality. |
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