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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Food Microbiology
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1404795
This article is part of the Research Topic Impact of Dairy Farming on the Safety of Raw Milk and Milk Products View all 5 articles

Tracking the Microbial Communities from the Farm to the Processing Facility of a Washed-Rind Cheese Operation

Provisionally accepted
Tara Wilson Tara Wilson 1,2Yueqi Xi Yueqi Xi 1,2Myra Siddiqi Myra Siddiqi 1,2Gisele LaPointe Gisele LaPointe 3*
  • 1 Department of Food Science, University of Guelph, Guelph, Ontario, Canada
  • 2 Dairy at Guelph, Guelph, Ontario, Canada
  • 3 Department of Food Science and Nutrition, University of Guelph, Guelph, Québec, Canada

The final, formatted version of the article will be published soon.

    Milk residue and the accompanying biofilm accumulation in milking systems can compromise the microbial quality of milk and the downstream processes of cheese production. Over a six-month study, the microbial ecosystems of milk (n=24), tap water (n=24) and environmental swabs (n=384) were cultured by plating decimal dilutions to obtain viable counts of total aerobic mesophilic lactoseutilizing bacteria (lactose-M17), lactic acid bacteria (MRS), yeasts and molds (Yeast, Glucose, Chloramphenicol (YGC) medium). Viable aerobic lactose-M17 plate counts of milk remained well below 4.7 log CFU/ml over five of the months, except for one week in November where milk at the facility exceeded 5 log CFU/ml. Swab samples of the farm milking equipment showed consistent viable counts after sanitation, while the bulk tank swabs contained the lowest counts. Viable counts from swabs of the facility were generally below the detection limit in the majority of samples with occasional residual contamination on some food contact surfaces. Extracted DNA was amplified using primers targeting the V3-V4 region of the 16S rRNA gene, and the amplicons were sequenced by MiSeq to determine the shared microbiota between the farm and the processing facility (8 genera).Culture independent analysis of bacterial taxa in milk, water and residual contamination after sanitation with swab samples revealed the shared and distinct microbiota between the sample types of both facilities. Amplicon sequence variants (ASVs) of the V3-V4 region of the 16S rRNA gene revealed that the microbiota of milk samples had lower diversity than water or environmental swabs (279 ASVs compared to 3,444 in water and 8,747 in environmental swabs). Brevibacterium and Yaniella (both ActinobacteriaActinomycetota) were observed in all sampling types. Further studies will include whole genome sequencing of Brevibacterium spp. isolates to determine their functionality and diversity within the system.

    Keywords: Milk quality, Cheese, amplicon sequence variants, microbial ecology, Sanitation, Tap water

    Received: 21 Mar 2024; Accepted: 08 Aug 2024.

    Copyright: © 2024 Wilson, Xi, Siddiqi and LaPointe. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Gisele LaPointe, Department of Food Science and Nutrition, University of Guelph, Guelph, G1V 0A6, Québec, Canada

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.