Browsing by Author "Yalew Tefera"

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    Study on Prevalence of Salmonella in Cottage Cheese and Cheese Made from Pasteurized Milk and Its Public Health Importance in Debre Zeit, Ethiopia
    (Addis Ababa University, 2011-06-01) Yalew Tefera; Akafite Teklu
    This study was undertaken to determine the prevalence of Salmonella spp . in cottage cheese and cheese made from pasteurized milk in Debre Zeit and to assess the effect of storage time on isolation rate of Salmonella from cottage cheese. Samples for analysis were collected from Debre Zeit open market, Adada Dairy Processing Association and Genesis farms from September 2010 to April 2011. All together 384 cheeses (192 cottage and 192 cheese made from pasteurized milk) were collected and analyzed for the prevalence of Salmonella. Isolation and identification was performed according Global Salm-Surv (2003) and ISO 6579 (2002) standard methods. A total of 6 Salmonella species were recovered from 384 of the samples analyzed (1.6%). All the isolated Salmonella species were from cottage cheese (3.13%) and no Salmonella species were isolated form samples brought from Adaa Dairy Processing Association and Genesis farms. There was statistically significant (P = 0.004) difference in the prevalence of Salmonella between cottage cheese and cheese made from pasteurized milk. Statistically significant (P = 0.027) variation was also observed in the isolation rate of Salmonella in the storage time of cottage cheese in which higher prevalence was observed in cottage cheese stored for only one day. The results of the present study indicated that the temperature used for making cottage cheese in the study area is not sufficient to destroy Salmonella totally or contaminated after making the cheese. Therefore, it poses public health risk to the consumer. The pasteurization temperature in pasteurized milk used for cheese making in the milk processing pl ants is sufficient to kill Salmonella. This study also revealed that the fresh cottage cheese have higher Salmonella isolation rate than the stored cheese