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The Evolving Role of Coliforms As Indicators of Unhygienic Processing Conditions in Dairy Foods
Testing for coliforms has a long history in the dairy industry and has helped to identify raw milk and dairy products that may have been exposed to unsanitary conditions. Coliform standards are included in a number of regulatory documents (e.g., the U.S. Food and Drug Administration’s Grade “A” Past...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Frontiers Media S.A.
2016
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5043024/ https://www.ncbi.nlm.nih.gov/pubmed/27746769 http://dx.doi.org/10.3389/fmicb.2016.01549 |
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author | Martin, Nicole H. Trmčić, Aljoša Hsieh, Tsung-Han Boor, Kathryn J. Wiedmann, Martin |
author_facet | Martin, Nicole H. Trmčić, Aljoša Hsieh, Tsung-Han Boor, Kathryn J. Wiedmann, Martin |
author_sort | Martin, Nicole H. |
collection | PubMed |
description | Testing for coliforms has a long history in the dairy industry and has helped to identify raw milk and dairy products that may have been exposed to unsanitary conditions. Coliform standards are included in a number of regulatory documents (e.g., the U.S. Food and Drug Administration’s Grade “A” Pasteurized Milk Ordinance). As a consequence, detection above a threshold of members of this method-defined, but diverse, group of bacteria can result in a wide range of regulatory outcomes. Coliforms are defined as aerobic or facultatively anaerobic, Gram negative, non-sporeforming rods capable of fermenting lactose to produce gas and acid within 48 h at 32–35°C; 19 genera currently include at least some strains that represent coliforms. Most bacterial genera that comprise the coliform group (e.g., Escherichia, Klebsiella, and Serratia) are within the family Enterobacteriaceae, while at least one genus with strains recognized as coliforms, Aeromonas, is in the family Aeromonadaceae. The presence of coliforms has long been thought to indicate fecal contamination, however, recent discoveries regarding this diverse group of bacteria indicates that only a fraction are fecal in origin, while the majority are environmental contaminants. In the US dairy industry in particular, testing for coliforms as indicators of unsanitary conditions and post-processing contamination is widespread. While coliforms are easily and rapidly detected, and are not found in pasteurized dairy products that have not been exposed to post-processing contamination, advances in knowledge of bacterial populations most commonly associated with post-processing contamination in dairy foods has led to questions regarding the utility of coliforms as indicators of unsanitary conditions for dairy products. For example, Pseudomonas spp. frequently contaminate dairy products after pasteurization, yet they are not detected by coliform tests. This review will address the role that coliforms play in raw and finished dairy products, their sources and the future of this diverse group as indicator organisms in dairy products. |
format | Online Article Text |
id | pubmed-5043024 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-50430242016-10-14 The Evolving Role of Coliforms As Indicators of Unhygienic Processing Conditions in Dairy Foods Martin, Nicole H. Trmčić, Aljoša Hsieh, Tsung-Han Boor, Kathryn J. Wiedmann, Martin Front Microbiol Microbiology Testing for coliforms has a long history in the dairy industry and has helped to identify raw milk and dairy products that may have been exposed to unsanitary conditions. Coliform standards are included in a number of regulatory documents (e.g., the U.S. Food and Drug Administration’s Grade “A” Pasteurized Milk Ordinance). As a consequence, detection above a threshold of members of this method-defined, but diverse, group of bacteria can result in a wide range of regulatory outcomes. Coliforms are defined as aerobic or facultatively anaerobic, Gram negative, non-sporeforming rods capable of fermenting lactose to produce gas and acid within 48 h at 32–35°C; 19 genera currently include at least some strains that represent coliforms. Most bacterial genera that comprise the coliform group (e.g., Escherichia, Klebsiella, and Serratia) are within the family Enterobacteriaceae, while at least one genus with strains recognized as coliforms, Aeromonas, is in the family Aeromonadaceae. The presence of coliforms has long been thought to indicate fecal contamination, however, recent discoveries regarding this diverse group of bacteria indicates that only a fraction are fecal in origin, while the majority are environmental contaminants. In the US dairy industry in particular, testing for coliforms as indicators of unsanitary conditions and post-processing contamination is widespread. While coliforms are easily and rapidly detected, and are not found in pasteurized dairy products that have not been exposed to post-processing contamination, advances in knowledge of bacterial populations most commonly associated with post-processing contamination in dairy foods has led to questions regarding the utility of coliforms as indicators of unsanitary conditions for dairy products. For example, Pseudomonas spp. frequently contaminate dairy products after pasteurization, yet they are not detected by coliform tests. This review will address the role that coliforms play in raw and finished dairy products, their sources and the future of this diverse group as indicator organisms in dairy products. Frontiers Media S.A. 2016-09-30 /pmc/articles/PMC5043024/ /pubmed/27746769 http://dx.doi.org/10.3389/fmicb.2016.01549 Text en Copyright © 2016 Martin, Trmčić, Hsieh, Boor and Wiedmann. http://creativecommons.org/licenses/by/4.0/ 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. |
spellingShingle | Microbiology Martin, Nicole H. Trmčić, Aljoša Hsieh, Tsung-Han Boor, Kathryn J. Wiedmann, Martin The Evolving Role of Coliforms As Indicators of Unhygienic Processing Conditions in Dairy Foods |
title | The Evolving Role of Coliforms As Indicators of Unhygienic Processing Conditions in Dairy Foods |
title_full | The Evolving Role of Coliforms As Indicators of Unhygienic Processing Conditions in Dairy Foods |
title_fullStr | The Evolving Role of Coliforms As Indicators of Unhygienic Processing Conditions in Dairy Foods |
title_full_unstemmed | The Evolving Role of Coliforms As Indicators of Unhygienic Processing Conditions in Dairy Foods |
title_short | The Evolving Role of Coliforms As Indicators of Unhygienic Processing Conditions in Dairy Foods |
title_sort | evolving role of coliforms as indicators of unhygienic processing conditions in dairy foods |
topic | Microbiology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5043024/ https://www.ncbi.nlm.nih.gov/pubmed/27746769 http://dx.doi.org/10.3389/fmicb.2016.01549 |
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