Salazar Joelle K, Gonsalves Lauren J, Fay Megan, Ramachandran Padmini, Schill Kristin M, Tortorello Mary Lou
Division of Food Processing Science and Technology, Office of Food Safety, U. S. Food and Drug Administration, Bedford Park, IL, United States.
Division of Microbiology, Office of Food Safety, U. S. Food and Drug Administration, College Park, MD, United States.
Front Microbiol. 2021 Mar 12;12:642789. doi: 10.3389/fmicb.2021.642789. eCollection 2021.
Unpasteurized milk is used to produce aged artisanal cheeses, which presents a safety concern due to possible contamination with foodborne pathogens, especially . The objective of this study was to examine the composition of the bacterial community in unpasteurized milk used to prepare Gouda cheese artificially contaminated with (~1 log CFU/ml) and assess the community dynamics and their potential interaction with during a 90-day ripening period using targeted 16S rRNA sequencing. The diversity of bacterial taxa in three batches of unpasteurized milk was not significantly different, and the microbiomes were dominated by species of , , , and . The highest relative abundances were observed for (31.84-78.80%) and unidentified operational taxonomic units (OTUs) of (7.56-45.27%). After manufacture, both with and without -contaminated unpasteurized milk, Gouda cheese was dominated by starter culture bacteria (including subsp. , , bv. diacetylactis, and ), in addition to unassigned members in the taxa and . During ripening there was an overall decrease in abundance and an increase in the number of taxa with relative abundances >0.1%. After 90-day ripening, a total of 82 and 81 taxa were identified in the Gouda cheese with and without , respectively. Of the identified taxa after ripening, 31 (Gouda cheese with ) and 56 (Gouda cheese without ) taxa had relative abundances >0.1%; 31 were shared between the two types of Gouda cheese, and 25 were unique to the Gouda cheese without added . No unique taxa were identified in the Gouda cheese with the added . This study provides information on the dynamics of the bacterial community in Gouda cheese during ripening, both with and without the addition of .
未杀菌的牛奶用于生产陈年手工奶酪，由于可能被食源性病原体污染，这存在安全隐患，尤其是……本研究的目的是检测用于制备人工污染了……（约1 log CFU/ml）的高达干酪的未杀菌牛奶中细菌群落的组成，并使用靶向16S rRNA测序评估在90天的成熟期间群落动态及其与……的潜在相互作用。三批未杀菌牛奶中细菌分类群的多样性没有显著差异，微生物群落以……、……、……和……的物种为主。观察到……（31.84 - 78.80%）和未鉴定的……操作分类单元（OTU）（7.56 - 45.27%）的相对丰度最高。制作后，无论是否使用污染的未杀菌牛奶，高达干酪均以发酵剂培养细菌为主（包括……亚种、……、……双乙酰乳酸亚种和……），此外还有……分类群中未分类的成员。在成熟过程中，……丰度总体下降，相对丰度>0.1%的分类群数量增加。经过90天的成熟，在添加和未添加……的高达干酪中分别鉴定出总共82个和81个分类群。成熟后鉴定出的分类群中，31个（添加……的高达干酪）和56个（未添加……的高达干酪）分类群的相对丰度>0.1%；两种类型的高达干酪共有31个分类群，25个分类群是未添加……的高达干酪所特有的。在添加……的高达干酪中未鉴定出独特的分类群。本研究提供了有关高达干酪在成熟过程中细菌群落动态的信息，无论是否添加……。
