Prevalence of Salmonella Species in Milk and Dairy Products in Major Milk Shade of Oromia, Ethiopia

Abstract

Background: Foods of animal origin are major vehicles of Salmonella infections and a serious public health problem with increasing concern in the world, particularly for developing countries. More recently review studies on the prevalence of Salmonella spp. in dairy products demonstrate, it has been a median of 6% in raw milk and dairy products. However, almost all prior works in this area are limited to biochemical confirmation of suspected Salmonella spp. isolates from dairy a product that has high uncertainty to confirm. Due to this almost all report of the prevalence of Salmonella spp. in dairy products as well as raw milk was highly varied. Besides, almost all prior report in the prevalence of Salmonella spp. in dairy product in Ethiopia takes no consideration of the dairy value chain to identify major point of contamination of the product. To overcome the shortcomings of previous studies molecular techniques as well as milk and dairy value chain in the country were used to confirm the prevalence of Salmonella spp. in each value chain. Methods: A cross-sectional study was conducted on milk and dairy products in Welmera, Bishoftu, Asella, and Fiche milk shades of the Oromia region of Ethiopia from December to March 2020 to determine the prevalence and of Salmonella spp. A total of 480 samples of dairy products (192 raw milk from producers and collector, 192 pasteurized milk from processer and retailer, and 96 cottage cheese from producer and retailer value chain) were collected using simple random techniques from producers, collectors, processors, and retailer value chains. The samples were tested for Salmonella using Iso 6579-1: 2008 methods. The risk factor for contamination of these dairy products across the dairy value-chain was done using pre-tested questionnaires.Results: Among 480 samples 71 samples were confirmed for Salmonella spp. using latex agglutination test and molecularly by confirming the presence highly conserved region of the invA gene. The overall prevalence of 14.79% (71/480) 21.35% raw milk, 12.5% pasteurized milk, and 6.5% cottage cheeses were recorded from the total tested samples. Among dairy products in the study area; raw milk was the highest Salmonella prevalence followed by Pasteurized milk. In the dairy value chain, the highest prevalence of 62.5% was observed in raw milk from Bishoftu fo1lowed by 54.17% of pasteurized milk in Fiche. The prevalence of Salmonella among the study area was 9.6% (8/120), in Welmera, 33.6% (28/120), in Bishoftu, 16.8% (14/120) in Asella, and 25.2% (21/120) in Fiche.Conclusions: The result of this study indicates the safety of milk and other dairy product in the region were substandard of East African standard. Therefore, strict hygienic approaches and quality control measures should be applied to improve the safety of the products. Awareness creation should be required for producers, retailers, processors, and consumers regarding the quality and safety of milk and other dairy products.

Keywords: Prevalence, Salmonella spp, Dairy product

DOI: 10.7176/JNSR/13-1-01

Publication date: January 31^st 2022