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Foodborne pathogens in unpasteurized milk in Sweden

Artursson, Karin; Schelin, Jenny LU ; Thisted Lambertz, Susanne ; Hansson, Ingrid and Olsson Engvall, Eva (2018) In International Journal of Food Microbiology 284. p.120-127
Abstract
Raw milk may be a risk for public health if it is contaminated with zoonotic pathogens. To study the prevalence
in unpasteurized milk from Swedish farms, bovine and small ruminant dairy farms were sampled. Since the
sampling method and transport conditions may influence the outcome of analyses, efforts were made to optimize
the methodology. Culturing of bacteria was done from in-line milk filters collected from the milk pipe at the
point where it enters the milk bulk tank at the farms and this way of sampling was compared to sampling bulk
tank milk (BTM) directly. Analysing milk filters were found to be superior to analysing BTM directly. Conditions
for transport of milk filter samples were further improved by the... (More)
Raw milk may be a risk for public health if it is contaminated with zoonotic pathogens. To study the prevalence
in unpasteurized milk from Swedish farms, bovine and small ruminant dairy farms were sampled. Since the
sampling method and transport conditions may influence the outcome of analyses, efforts were made to optimize
the methodology. Culturing of bacteria was done from in-line milk filters collected from the milk pipe at the
point where it enters the milk bulk tank at the farms and this way of sampling was compared to sampling bulk
tank milk (BTM) directly. Analysing milk filters were found to be superior to analysing BTM directly. Conditions
for transport of milk filter samples were further improved by the addition of Cary Blair transport medium, which
significantly increased the number of positive samples for pathogenic bacteria. The isolation of several foodborne
pathogens from milk filters was demonstrated. The prevalence of samples with Staphylococcus aureus was
71% and 64%, and Listeria spp. 21% and 29% from dairy cow and goat/sheep farms, respectively. Campylobacter
jejuni, Yersinia enterocolitica and verotoxigenic Escherichia coli (VTEC) O157 were detected in 9%, 2% and 2% of
samples from bovine milk, respectively.
We conclude that the choice of sampling method and sample handling influence the results of bacterial
culturing. From the results of this study, we strongly recommend to sample in-line milk filters instead of BTM
directly and to use Cary Blair medium during transport, especially if the samples are to be analysed for
Campylobacter spp. and/or Listeria spp. The findings also show that unpasteurized milk from Swedish farms
occasionally contain bacteria with zoonotic potential. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
International Journal of Food Microbiology
volume
284
pages
120 - 127
publisher
Elsevier
external identifiers
  • scopus:85048122529
ISSN
0168-1605
DOI
10.1016/j.ijfoodmicro.2018.05.015
language
English
LU publication?
yes
id
dca9cef0-25ab-42c4-8148-8de7c13fe391
date added to LUP
2018-06-11 15:49:12
date last changed
2019-03-19 03:56:01
@article{dca9cef0-25ab-42c4-8148-8de7c13fe391,
  abstract     = {Raw milk may be a risk for public health if it is contaminated with zoonotic pathogens. To study the prevalence<br/>in unpasteurized milk from Swedish farms, bovine and small ruminant dairy farms were sampled. Since the<br/>sampling method and transport conditions may influence the outcome of analyses, efforts were made to optimize<br/>the methodology. Culturing of bacteria was done from in-line milk filters collected from the milk pipe at the<br/>point where it enters the milk bulk tank at the farms and this way of sampling was compared to sampling bulk<br/>tank milk (BTM) directly. Analysing milk filters were found to be superior to analysing BTM directly. Conditions<br/>for transport of milk filter samples were further improved by the addition of Cary Blair transport medium, which<br/>significantly increased the number of positive samples for pathogenic bacteria. The isolation of several foodborne<br/>pathogens from milk filters was demonstrated. The prevalence of samples with Staphylococcus aureus was<br/>71% and 64%, and Listeria spp. 21% and 29% from dairy cow and goat/sheep farms, respectively. Campylobacter<br/>jejuni, Yersinia enterocolitica and verotoxigenic Escherichia coli (VTEC) O157 were detected in 9%, 2% and 2% of<br/>samples from bovine milk, respectively.<br/>We conclude that the choice of sampling method and sample handling influence the results of bacterial<br/>culturing. From the results of this study, we strongly recommend to sample in-line milk filters instead of BTM<br/>directly and to use Cary Blair medium during transport, especially if the samples are to be analysed for<br/>Campylobacter spp. and/or Listeria spp. The findings also show that unpasteurized milk from Swedish farms<br/>occasionally contain bacteria with zoonotic potential.},
  author       = {Artursson, Karin and Schelin, Jenny and Thisted Lambertz, Susanne  and Hansson, Ingrid  and Olsson Engvall, Eva },
  issn         = {0168-1605},
  language     = {eng},
  month        = {05},
  pages        = {120--127},
  publisher    = {Elsevier},
  series       = {International Journal of Food Microbiology},
  title        = {Foodborne pathogens in unpasteurized milk in Sweden},
  url          = {http://dx.doi.org/10.1016/j.ijfoodmicro.2018.05.015},
  volume       = {284},
  year         = {2018},
}