The Core and Seasonal Microbiota of Raw Bovine Milk in Tanker Trucks and the Impact of Transfer to a Milk Processing Facility.
The Core and Seasonal Microbiota of Raw Bovine Milk in Tanker Trucks and the Impact of Transfer to a Milk Processing Facility.
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DOI：
10.1128/mbio.00836-16
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发表时间：
2016-08-23
期刊：
影响因子：
6.4
通讯作者：
Marco ML
中科院分区：
文献类型：
--
作者：
Kable ME;Srisengfa Y;Laird M;Zaragoza J;McLeod J;Heidenreich J;Marco ML
目前，对油罐车中原料奶的细菌组成以及在商业加工设施中转移和储存该奶的结果还没有很好的了解。我们着手鉴定用于大规模乳制品生产的原料奶中的细菌。采用群落16 S rRNA基因测序方法，对来自加州圣华金河谷两个乳品加工厂的899辆罐车的原料牛乳样品进行了分析。该分析揭示了高度多样的细菌种群，表现出季节性差异。在春季采集的生牛奶中含有最多样化的细菌群落，放线菌的细胞总数和比例最高。即使有这种复杂性，也存在核心微生物群，由29个分类组和高比例的链球菌和葡萄球菌以及未鉴定的梭菌目成员组成。牛奶样品也收集了5个大容量筒仓和13至25油罐车，其内容物卸载到他们每个人在2天的夏天。将牛奶转移到储存筒仓导致两种社区类型。一组筒仓含有高比例的链球菌属。在这方面与装满它们的油轮相似。在另一组筒仓中发现的群落是独特的，并以不动杆菌属为主。总体而言，尽管高度多样化的油轮牛奶社区结构，不同的牛奶细菌群落中选择的加工设施的环境。这些知识可以为开发新的卫生程序和过程控制提供信息，以确保在全球范围内持续生产安全和高质量的乳制品。原料奶含有多种细菌，这些细菌是液体奶和（发酵）乳制品质量和安全的关键决定因素。这些细菌在运输、储存和加工过程中进入农场牛奶。虽然巴氏杀菌法可以消灭病原体，但并不是所有的细菌及其相关的酶都能被消灭。我们对原料奶在到达主要乳制品加工厂后不久和储存后不久的细菌组成进行了全面分析，结果表明，牛奶微生物群的群落高度多样化。即使存在这些差异，核心微生物群也表现出明显的季节性趋势。值得注意的是，加工设施的影响超过了原料奶微生物组的影响，并且在转移后的短时间内，微生物组成在一些但不是所有筒仓内发生了明显变化。这些知识可用于告知清洁和卫生程序，以及预测原料奶中的微生物群落，从而产生高质量或有缺陷的产品。
Currently, the bacterial composition of raw milk in tanker trucks and the outcomes of transfer and storage of that milk at commercial processing facilities are not well understood. We set out to identify the bacteria in raw milk collected for large-scale dairy product manufacturing. Raw bovine milk samples from 899 tanker trucks arriving at two dairy processors in San Joaquin Valley of California during three seasons (spring, summer, and fall) were analyzed by community 16S rRNA gene sequencing. This analysis revealed highly diverse bacterial populations, which exhibited seasonal differences. Raw milk collected in the spring contained the most diverse bacterial communities, with the highest total cell numbers and highest proportions being those of Actinobacteria. Even with this complexity, a core microbiota was present, consisting of 29 taxonomic groups and high proportions of Streptococcus and Staphylococcus and unidentified members of Clostridiales. Milk samples were also collected from five large-volume silos and from 13 to 25 tankers whose contents were unloaded into each of them during 2 days in the summer. Transfer of the milk to storage silos resulted in two community types. One group of silos contained a high proportion of Streptococcus spp. and was similar in that respect to the tankers that filled them. The community found in the other group of silos was distinct and dominated by Acinetobacter. Overall, despite highly diverse tanker milk community structures, distinct milk bacterial communities were selected within the processing facility environment. This knowledge can inform the development of new sanitation procedures and process controls to ensure the consistent production of safe and high-quality dairy products on a global scale. Raw milk harbors diverse bacteria that are crucial determinants of the quality and safety of fluid milk and (fermented) dairy products. These bacteria enter farm milk during transport, storage, and processing. Although pathogens are destroyed by pasteurization, not all bacteria and their associated enzymes are eliminated. Our comprehensive analyses of the bacterial composition of raw milk upon arrival and shortly after storage at major dairy processors showed that the communities of milk microbiota are highly diverse. Even with these differences, there was a core microbiota that exhibited distinct seasonal trends. Remarkably, the effects of the processing facility outweighed those of the raw milk microbiome and the microbial composition changed distinctly within some but not all silos within a short time after transfer. This knowledge can be used to inform cleaning and sanitation procedures as well as to enable predictions of the microbial communities in raw milk that result in either high-quality or defective products.