Prevalence and Antimicrobial Resistance of Salmonella Enterica in Cow Milk and Cottage Cheese in Major Milk Shades of Oromia Region Ethiopia

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Addis Ababa University


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. There has been a median of 6% in raw milk and dairy products but most prior works in this area have focused on biochemical confirmation from dairy isolates. Almost all report of the prevalence of Salmonella spp. in dairy products as well as raw milk was highly varied. To address the limitations of earlier research, molecular methods and the country's milk and dairy value chain were tested. Risk factors related to pathogen prevalence, antibiotic resistance testing, and PCR-based pathogen serotyping were performed. A cross-sectional study was conducted on milk and cottage cheese in major milk shades of the Oromia region of Ethiopia from December to March 2020 to determine the prevalence and of S. enterica. A total of 480 samples (384 milk and 96 cottage cheese) 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. Selective plating reveals a higher prevalence of S. enterica among 480 samples, with 67.5% (324/480) for Hektoen enteric agar and 40% (192/480) for Xylose lysine desoxycholate agar while 14.8% (71/480) molecularly by detecting the presence of a highly conserved region of the invA gene. Raw milk accounted for 21.3% (41/192) of the overall prevalence, whereas pasteurized milk accounted for 12.5% (24/192), and cottage cheese accounted for 6.25% (6/96). The collector value chain received 20.8% (20/96), whereas Bishoftu received 23.3% (28/120). Salmonella infection was found to have a statistically significant relationship with access to training and the water temperature with which udder was washed in producers; gender and milk filtration in collectors; sieving in milk processors; and production system in cottage cheese retailer value chain respectively The greatest serotype was S. Heidelberg (59.1%), and clindamycin showed full resistance among 10 antimicrobials, whereas ceftriaxone showed 81.7% susceptibility. The results of this investigation show that there were problems relating to the safety of milk and cottage cheese in the area. 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.



Cottage Cheese, Pcr, Prevalence, Salmonella Enterica, Serotyping