Veterinary and Animal Sciences
Turkish Journal of Veterinary and Animal SciencesInvestigation on the Viability Span of Listeria monocytogenes During the Ripening of Brined Şavak Cheese
Fırat Üniversitesi, Veteriner Fakültesi,Besin Hijyeni ve Teknolojisi Anabilim Dalı, Elazığ- TÜRKİYE
Aba Müslüm GÜVEN
Kafkas Üniversitesi, Veteriner Fakültesi, Besin Hijyeni ve Teknolojisi Anabilim Dalı, Kars - TÜRKİYE
Abstract: The purpose of this study was to determine the viability span of listeria monocytogenes during the ripening of brined şavak white cheese which is produced by and has a significant role in the nutrition of people living in Elazığ, Tunceli, Bingöl and Erzincan. Ewes milk was inoculated with various strains (4b, 1/2c and 1/2a) of listeria monocytogenes at the rate of 1.00x103 - 1.35x106 cells/ml and then şavak cheese was produced from the milk. The cheese samples were analysed after 0, 15, 30, 60, 90 and 120 days of ripening for the numbers of listeria monocytogenes with the direct plating method and enrichment methods (at 30ºC for 48 hours or 7 days). The numbers of listeria monocytogenes were 3.70x105 - 6.88x105 cfu/g in the curd, which fell to 0.50x10-7.08x10 cfu/g in the cheese after 120 days of ripening and the trends were almost identical. The numbers of listeria monocytogenes determined with the enrichment methods, followed different paths during the ripening. The pH of the cheese until day 60, in all series of the samples. Later in the experiment (days 90 and 120) the values increased. It was conluded that it might be possible to isolate listeria monocytogenes from şavak cheese made from raw ewes milk containing a minimum of 1.00x103 cells/ml; using direct isolation rate in enrichment at 30ºC for 48 hours is higher than in enrichment at 30ºC for 7 days. In addition, it was evident that listeria monocytogenes survive until the end of the ripening process and pose a danger to public health.
Key Words: Listeria monocytogenes, white cheese, viability span, Inocülation
Turk. J. Vet. Anim. Sci. 1999; 23: 317-328.
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Other articles published in the same issue: Turk. J. Vet. Anim. Sci.,vol.23,iss.EK2.