Isolation, Identification and Antibacterial Susceptibility Pattern of Salmonella Spp. from Soya Milk Sold in Kaduna State University (main Campus)

ABSTRACT This study focuses on the isolation, identification, and antimicrobial susceptibility profile of Salmonella spp. from soymilk sold at Kaduna State University (KASU)(Main Campus). Soymilk, a popular beverage with high nutritional value, poses potential public health risks when contaminated by pathogenic microorganisms such as Salmonella, which is a major cause of foodborne illnesses globally. Samples were aseptically collected from various vendors at KASU and transported to the laboratory for microbiological analysis. The study involved the use of standardized procedures for sterilization, media preparation, serial dilution, and isolation of Salmonella spp. The bacterial isolates were subjected to Gram staining, a series of biochemical tests (catalase, oxidase, methyl red, indole, Voges-Proskauer, citrate utilization), and antibiotic susceptibility testing using the Kirby-Bauer disc diffusion method. The results revealed that Salmonella isolates exhibited characteristic morphological and biochemical properties typical of the species. Specifically, isolates were Gram-negative, rod-shaped, and motile. The colonies were colorless with black centers on Salmonella Shigella Agar due to hydrogen sulfide production. Biochemical tests confirmed the presence of catalase and methyl red-positive reactions across all samples, while oxidase, indole, and Voges-Proskauer tests were negative. The antibiotic susceptibility profiles demonstrated high susceptibility to multiple antibiotics, including Ciprofloxacin, Streptomycin, and Chloramphenicol, with varying degrees of effectiveness. The findings underscore the importance of regular monitoring and implementing strict hygienic practices during the production and sale of soymilk to ensure consumer safety. The high susceptibility of Salmonella isolates to a range of antibiotics suggests potential for effective treatment of infections.