Veterinarska stanica, Vol. 51 No. 5, 2020.
Original scientific paper
https://doi.org/10.46419/vs.51.5.9
Detection of pathogenic bacteria in raw milk and dairy products with special regard to Yersinia enterocolitica
Vesna Jaki Tkalec
orcid.org/0000-0001-5944-7227
; Croatian Veterinary Institute, Veterinary Department Križevci, Križevci, Croatia
Sanja Furmeg
; Croatian Veterinary Institute, Veterinary Department Križevci, Križevci, Croatia
Maja Kiš
; Croatian Veterinary Institute, Veterinary Department Križevci, Križevci, Croatia
Jadranka Sokolović
; Croatian Veterinary Institute, Veterinary Department Križevci, Križevci, Croatia
Miroslav Benić
orcid.org/0000-0001-7594-520X
; Croatian Veterinary Institute, Zagreb, Croatia
Luka Cvetnić
; Croatian Veterinary Institute, Zagreb, Croatia
Željko Pavlinec
; Croatian Veterinary Institute, Veterinary Department Križevci, Križevci, Croatia
Silvio Špičić
orcid.org/0000-0001-8317-5831
; Croatian Veterinary Institute, Zagreb, Croatia
Željko Cvetnić
; Croatian Veterinary Institute, Veterinary Department Križevci, Križevci, Croatia
Abstract
In northwestern Croatia, soft fresh cheese is produced using traditional, unwritten recipes of raw cow milk. Milk is an ideal substrate for the growth and reproduction of numerous microorganisms, many zoonotic
agents and the species Y. enterocolitica. In this study, 159 samples were tested: 109 samples of raw cow milk and 50 samples of fresh cow cheese and cream. Y. enterocolitica was detected in 2 (1.8%) samples of raw milk. E. coli was detected in 16 (32%) of 50 samples of dairy products (cheese and cream). S. aureus was detected in 12 (24%)
samples and L. innocua in 1 (2%) sample. Additionally, 15 (13.8%) samples of raw milk and 24 (48%) samples of fresh cheese and cream also harboured enterobacteria, identified biochemically as: S. marcescens, S. liquefaciens, M. morganii, C. freundii and C. braakii. Salmonella and L. monocytogenes were detected in any of the samples. After the biochemical identification, two strains identified as Y. enterocolitica were examined at the molecular level, and the molecular
test confirmed the result in only one sample, which is comparable to the results of other studies. Due to the demanding identification of the bacterial species Y. enterocolitica, the combined application of breeding and molecular methods produces more reliable and faster identification results. Raw milk and crude milk cream are a source of pathogenic microorganisms (E. coli and S. aureus) and other enterobacteria, while
this study also found the presence of the pathogenic bacterial species Y. enterocolitica, presenting a potential consumer health risk in the Republic of Croatia. Y. enterocolitica is considerably resistant to food production processes (disinfection, low pH, salinity, survival in cold conditions) and deserves greater attention and supervision in food
production in the future.
Keywords
Y. enterocolitica; bacteria; raw milk; cheese and cream
Hrčak ID:
241535
URI
Publication date:
1.7.2020.
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