原奶和乳制品中的微生物污染会对产品质量和人类健康产生不利影响。在这项研究中,有氧板计数,需氧芽孢杆菌丰度,嗜热需氧芽孢杆菌丰度,测定了435个原料乳中的碱性磷酸酶活性,451巴氏杀菌牛奶,和从中国13个省(市)收集的617份灭菌牛奶样品。大约9.89%和2.22%的生乳和巴氏杀菌乳样品超过了需氧平板计数的阈值,分别。原料奶中需氧芽孢杆菌的比例,巴氏杀菌牛奶,和灭菌牛奶为54.02%,14.41%,和1.30%,分别。原料乳中嗜热需氧芽孢杆菌的比例为7.36%,巴氏杀菌乳中的比例为4.88%,并且在灭菌牛奶中没有细菌计数。大约36.18%的原料奶样品含有>500,000mU/L的碱性磷酸酶活性,而9.71%的巴氏杀菌牛奶样品的含量>350mU/L。对于生牛奶,有氧平板计数之间存在正相关,需氧芽孢杆菌的丰度,和碱性磷酸酶活性,需氧芽孢杆菌丰度呈正相关,嗜热需氧芽孢杆菌计数,和碱性磷酸酶活性。对于巴氏灭菌的牛奶,有氧平板计数之间存在正相关,需氧芽孢杆菌的丰度,和嗜热需氧芽孢杆菌计数;然而,碱性磷酸酶活性与需氧平板计数呈负相关,需氧芽孢杆菌的丰度,和嗜热需氧芽孢杆菌丰富。这些结果促进了公众对公共卫生安全问题的认识和中国乳制品监管机构的参与。
Microbial contamination in raw milk and dairy products can detrimentally affect product quality and human health. In this study, the aerobic plate count, aerobic Bacillus abundance, thermophilic aerobic Bacillus abundance, and alkaline phosphatase activity were determined in 435 raw milk, 451 pasteurized milk, and 617 sterilized milk samples collected from 13 Chinese provinces (or municipalities). Approximately 9.89% and 2.22% of raw milk and pasteurized milk samples exceeded the threshold values for the aerobic plate count, respectively. The proportions of aerobic Bacillus in raw milk, pasteurized milk, and sterilized milk were 54.02%, 14.41%, and 1.30%, respectively. The proportions of thermophilic aerobic Bacillus species were 7.36% in raw milk and 4.88% in pasteurized milk samples, and no bacteria were counted in sterilized milk. Approximately 36.18% of raw milk samples contained >500,000 mU/L of alkaline phosphatase activity, while 9.71% of pasteurized milk samples contained >350 mU/L. For raw milk, there was a positive correlation between the aerobic plate count, the aerobic Bacillus abundance, and the alkaline phosphatase activity, and there was a positive correlation between the aerobic Bacillus abundance, the thermophilic aerobic Bacillus count, and the alkaline phosphatase activity. For pasteurized milk, there was a positive correlation between the aerobic plate count, the aerobic Bacillus abundance, and the thermophilic aerobic Bacillus count; however, the alkaline phosphatase activity had a negative correlation with the aerobic plate count, the aerobic Bacillus abundance, and the thermophilic aerobic Bacillus abundance. These results facilitate the awareness of public health safety issues and the involvement of dairy product regulatory agencies in
China.