Research Unit of Food Safety, Chinese Academy of Medical Science (2019RU014), NHC Key Laborarory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing 100022, China.
Int J Environ Res Public Health. 2023 Jan 19;20(3):1825. doi: 10.3390/ijerph20031825.
Microbial contamination in raw milk and dairy products can detrimentally affect product quality and human health. In this study, the aerobic plate count, aerobic abundance, thermophilic aerobic 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 in raw milk, pasteurized milk, and sterilized milk were 54.02%, 14.41%, and 1.30%, respectively. The proportions of thermophilic aerobic 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 abundance, and the alkaline phosphatase activity, and there was a positive correlation between the aerobic abundance, the thermophilic aerobic count, and the alkaline phosphatase activity. For pasteurized milk, there was a positive correlation between the aerobic plate count, the aerobic abundance, and the thermophilic aerobic count; however, the alkaline phosphatase activity had a negative correlation with the aerobic plate count, the aerobic abundance, and the thermophilic aerobic abundance. These results facilitate the awareness of public health safety issues and the involvement of dairy product regulatory agencies in China.
生乳及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。本研究对中国 13 个省（直辖市）采集的 435 份生乳、451 份巴氏杀菌乳和 617 份灭菌乳样品进行了需氧平板计数、需氧菌数、嗜温需氧菌数和碱性磷酸酶活性的测定。生乳和巴氏杀菌乳样品中，分别有 9.89%和 2.22%的样品超过需氧平板计数的阈值。生乳、巴氏杀菌乳和灭菌乳中的需氧菌比例分别为 54.02%、14.41%和 1.30%。生乳和巴氏杀菌乳中嗜温需氧菌的比例分别为 7.36%和 4.88%，而灭菌乳中未检出细菌。生乳样品中，约有 36.18%的样品碱性磷酸酶活性>500000 mU/L，而巴氏杀菌乳样品中，约有 9.71%的样品碱性磷酸酶活性>350 mU/L。生乳中，需氧平板计数、需氧菌数和碱性磷酸酶活性之间呈正相关，需氧菌数、嗜温需氧菌计数和碱性磷酸酶活性之间呈正相关。巴氏杀菌乳中，需氧平板计数、需氧菌数和嗜温需氧菌计数之间呈正相关；但碱性磷酸酶活性与需氧平板计数、需氧菌数和嗜温需氧菌数呈负相关。这些结果有助于提高公众对健康安全问题的认识，并促使中国乳制品监管机构参与其中。
