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Microbiological Safety of Fresh Tilapia ( Oreochromis niloticus) from Kenyan Fresh Water Fish Value Chains.
Journal article

Microbiological Safety of Fresh Tilapia ( Oreochromis niloticus) from Kenyan Fresh Water Fish Value Chains.

  • Onjong HA 1 Department of Food Science and Technology, Technical University of Kenya, P.O. Box 52428, 00200, Nairobi, Kenya.
  • Ngayo MO 2 Centre for Microbiology Research, Kenya Medical Research Institute, P.O. Box 54840, 00200, Nairobi, Kenya.
  • Mwaniki M 1 Department of Food Science and Technology, Technical University of Kenya, P.O. Box 52428, 00200, Nairobi, Kenya.
  • Wambui J 3 Institute for Food Safety and Hygiene, University of Zurich, Winterthurerstrasse 272, 8057 Zurich, Switzerland (ORCID: http://orcid.org/0000-0002-6071-5505 ).
  • Njage PMK 4 Division for Epidemiology and Microbial Genomics, National Food Institute, Technical University of Denmark, 2800 Kongens, Lyngby, Denmark.
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  • 2018-11-21
Published in:
  • Journal of food protection. - 2018
Microbiological safety
Nile tilapia fish
Pathogens
Animals
Cichlids
Colony Count, Microbial
Food Microbiology
Fresh Water
Gram-Negative Bacteria
Gram-Positive Bacteria
Kenya
Tilapia
Water Microbiology
English This study evaluated the microbiological safety of fresh Nile tilapia ( Oreochromis niloticus) from Kenyan fresh water fish value chains. One hundred seventy-six fish samples were analyzed. The microbial counts of hygiene indicators, total viable aerobic count (TVC), total coliforms, and fecal coliforms isolated by using culture techniques were enumerated, and microbial pathogens present in the fish samples were identified and characterized by using molecular methods. The diversity of bacterial isolates was determined by using the Shannon-Weaver diversity index. The mean of TVC in the samples was 4.44 log CFU/g. A comparison with the European Commission and International Commission on Microbiological Specifications for Foods standards showed two fish samples had counts above the 5.00 log CFU/g limit for TVC, and all the fish samples had total coliform and fecal coliform counts above 2.00 and 1.00 log CFU/g, respectively. Pathogenic strains, including Shiga toxin-producing and enteropathogenic Escherichia coli, Listeria monocytogenes, Yersinia enterocolitica, Klebsiella pneumoniae, and Salmonella enterica, were identified in the fish samples. The diversity of 1,608 bacterial isolates was higher in semiregulated chains than unregulated chains. The diversity was also high at the retail stage of the fish value chain. In conclusion, fresh Nile tilapia samples were above some of the set food safety standards and may be a source of foodborne pathogens. Further microbial risk assessment for detected pathogens is recommended to further support public health protection, taking into account growth, inactivation through cooking, processing, survival, and consumption.
Language
  • English
Open access status
closed
Identifiers
Persistent URL
https://sonar.rero.ch/global/documents/298611
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