Department of Food Science, Cornell University, Ithaca, NY 14853.
Department of Food Science, Cornell University, Ithaca, NY 14853.
J Dairy Sci. 2017 Dec;100(12):9933-9951. doi: 10.3168/jds.2017-12969.
Microbes that may be present in milk can include pathogens, spoilage organisms, organisms that may be conditionally beneficial (e.g., lactic acid bacteria), and those that have not been linked to either beneficial or detrimental effects on product quality or human health. Although milk can contain a full range of organisms classified as microbes (i.e., bacteria, viruses, fungi, and protozoans), with few exceptions (e.g., phages that affect fermentations, fungal spoilage organisms, and, to a lesser extent, the protozoan pathogens Cryptosporidium and Giardia) dairy microbiology to date has focused predominantly on bacteria. Between 1917 and 2017, our understanding of the microbes present in milk and the tools available for studying those microbes have changed dramatically. Improved microbiological tools have enabled enhanced detection of known microbes in milk and dairy products and have facilitated better identification of pathogens and spoilage organisms that were not known or well recognized in the early 20th century. Starting before 1917, gradual introduction and refinement of pasteurization methods throughout the United States and many other parts of the world have improved the safety and quality of milk and dairy products. In parallel to pasteurization, others strategies for reducing microbial contamination throughout the dairy chain (e.g., improved dairy herd health, raw milk tests, clean-in-place technologies) also played an important role in improving microbial milk quality and safety. Despite tremendous advances in reducing microbial food safety hazards and spoilage issues, the dairy industry still faces important challenges, including but not limited to the need for improved science-based strategies for safety of raw milk cheeses, control of postprocessing contamination, and control of sporeforming pathogens and spoilage organisms.
牛奶中可能存在的微生物包括病原体、腐败菌、条件有益菌（如乳酸菌）以及与产品质量或人类健康的有益或有害影响无关的菌。虽然牛奶可以包含被归类为微生物的各种生物体（即细菌、病毒、真菌和原生动物），但除了少数例外（例如影响发酵的噬菌体、真菌腐败菌，以及在较小程度上的原生动物病原体 Cryptosporidium 和 Giardia），迄今为止，乳品微生物学主要集中在细菌上。从 1917 年到 2017 年，我们对牛奶中存在的微生物以及研究这些微生物的工具的理解发生了巨大变化。改进的微生物学工具使我们能够更有效地检测牛奶和乳制品中的已知微生物，并更准确地识别在 20 世纪初未知或未被充分认识的病原体和腐败菌。早在 1917 年之前，巴氏杀菌方法在美国和世界许多其他地区的逐渐引入和改进就提高了牛奶和乳制品的安全性和质量。与巴氏杀菌并行的是，通过在整个乳品链中减少微生物污染的其他策略（例如，改善奶牛健康、原奶检测、原位清洁技术）也在提高微生物牛奶质量和安全性方面发挥了重要作用。尽管在减少微生物食品安全危害和腐败问题方面取得了巨大进展，但乳品行业仍面临着重要挑战，包括但不限于需要改进基于科学的策略来确保生乳奶酪的安全性、控制后加工污染以及控制芽孢形成病原体和腐败菌。
