Background
and Objective: Due
to low quantity of pathogens in foods, designing a broth medium to enrich
simultaneously several pathogens through a suitable time to a detectable level
is one of point of interest of many microbiologists. This study aimed to enrich
simultaneously three food-borne pathogens (Listeria monocytogenes,
Staphylococcus aureus and Enterohaemorrhagic Escherichia coli)
transferred by milk products.
Materials and Methods: This experimental
study was carried out in Kerman in 2013. First, a mixture of five enrichment
media, including TSB, TB, TSBYE, SEB and TSB (NaCl 1.5%) was provided. These
mediums were evaluated to enrich of L.monocytogenes, S.aureus and
Enterohaemorrhagic E. coli using culture method. Then sterilized and
pasteurized milk samples were artificially contaminated with these bacteria,
separately and in a mixture. The enrichment ability of these five broth media
was evaluated in three times (8, 18 and 24 hours).
Results: All five media were
able to enrich the pathogens in both single and triple contaminated tubes. The
bacteria in the contaminated milk were enriched through 8 hours, probably due
to use of the nutrients in the milk. However, growth of Listeria
monocytogenes and Staphylococcus aureus were inhibited in the
mentioned condition due to the inhibitory components of milk.
Conclusion: Based on results of
this study, incubation of the bacteria in SEB broth for 18 hours showed the
highest simultaneous enriching ability. Furthermore, it is the first report in
which Tryptose Broth was able to show a simultaneous enriching ability for
these pathogens.
Key words: Simultaneous, Listeria
monocytogenes, Staphylococcus aureus, Enterohaemorrhagic
Escherichia coli
Funding: This research was funded by
personal costs.
Conflict of interest: None declared.
Ethical
approval: The
Ethics Committee of Kerman University approved the study.
How
to cite this article: Abbaslou R, Kargar M,
Najafi A. Efficiency Assessment of Simultaneous Media to
Enrich Listeria Monocytogenes, Staphylococcus Aureus
and Enterohaemorrhagic Escherichia Coli.
J RafsanjanUniv Med Sci 2015 13(12): 1105-14.
[Farsi]
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