巴氏杀菌对原料羊乳卫生质量的影响

Influence of pasteurization in the goat milk sanitary quality

本文就巴氏杀菌条件对原料羊乳和贮存过程中巴氏杀菌羊乳的菌落总数和大肠菌群变化规律进行研究。不同污染程度的原料羊乳分别在63℃/30min、72℃/30s和85℃/15s下处理,乳样中菌落总数和大肠菌群变化差异极为显著(p<0.05)。随着巴氏杀菌强度的增大,污染程度相同乳样的巴氏杀菌效率依次增高,污染程度不同乳样的巴氏杀菌效率却依次降低。巴氏杀菌后轻度污染和中度污染的乳样在5℃贮存7d后,其菌落总数和大肠菌群变化不显著(p>0.05),均未超过巴氏杀菌乳国标GB19645-2010;重度污染的巴氏杀菌羊乳乳样在5℃贮存7d之后其菌落总数和大肠菌群已经显著超过巴氏杀菌乳国标GB19645-2010。因此原料羊乳在生产和贮存运输过程中要避免被微生物所污染,轻度和中度污染乳样的巴氏杀菌条件应选63℃/30min,贮存温度和时间应该控制在5℃/7d以内,以提高巴杀羊乳的品质和货架期。

In this paper,the effect of pasteurization conditions on variation of total plate count and coliforms with raw goat milk and during its storage process was studied. Raw goat milk with different pollution levels were treated in conditions of 63℃/30min,72℃/30s and 85℃/15s.The change of total plate count and coliforms in these goat milk samples was extremely different（p 〈 0.05）.With three groups of heat treatment conditions （63℃/30min,72%/30s and 85 ℃/15s）, efficiency of microbial disinfection with raw goat milk was increased and efficiency of pasteurization with different polluting milk samples was reduced. For slightly and moderately contaminated milk samples after pasteurization stored at 5℃/Td,their total plate count and coliforms did not change significantly（p 〉0.05）and did not exceed the pasteurized milk indicators in GB]9645-20]0, For heavily contaminated milk samples which was stored for 7d at 5℃ after pasteurization,its total plate count and coliforms had significantly exceeded pasteurized milk indicators in GB19645-2010.Therefore,contamination of raw goat milk by microorganisms should be avoided during the production, storage and transportation processes. In order to improve the quality and shelf life of pasteurized goat milk, pasteurization conditions should be chosen as 63℃/30min and storage temperature and time should be controlled with in 5℃/7d.