Prevalence of Salmonella organisms in fresh and smoke-dried fish within parts of Kaduna metropolis, Kaduna State, Nigeria

Abstract

Aquatic environments are the major reservoirs of Salmonella and fishery products have been recognized as major carrier of food-borne pathogens. To determine the prevalence of Salmonella in fish, 112 fresh and smoke-dried fish samples were pre-enriched and enriched with buffered peptone water and selenite broth respectively, before plating on Desoxycholate Citrate Agar. Of the 112 samples, 75% (84/112) were contaminated with non-lactose fermenters. Upon subjecting them to biochemical tests, 13.1% (11/84) of the Salmonella suspects showed reactions consistent with that of Salmonella species, Proteus 65.5% (55/84) and Citrobacter 21.4% (18/84) species. The total prevalence of Salmonella out of the 112 fish sampled was 9.8% (11/112). Salmonella species was slightly higher in the fiber tank farm 12.9% (95% CI: 5.134-28.852) than in the earthen pond 12.1% (95% CI: 4.816-27.326) but this association was not significant (Fishers exact test=1.0). Prevalence was higher in fresh fish 12.5% (95% CI: 6.472-22.775) compared to smoke-dried fish 6.25% (95% CI: 2.148-16.835), though this association was not statistically significant (Fishers exact test= 0.347). Among the dried fish, the prevalence was higher 9.5% (95% CI: 0.017-0.289) in the weight range 30-49.9g compared to the smallest weight range of 10-29.9g with prevalence of 4.0% (95% CI: 0.002-0.195). For the fresh fish, the prevalence was higher 14.04% (95% CI: 7.287-25.324) in shorter length fish of 20-39cm than the lengthier ones of 40-49cm with 0.0% (95% CI: 0.000-35.433) prevalence. This study has demonstrated the presence of Salmonella species in fresh and smoke-dried fish in parts of Kaduna metropolis, Kaduna State, Nigeria. This is of public health significance and poses a potential risk especially among immunocompromised consumers.

Keywords: Biochemical test, Earthen pond, Fresh fish, Fiber tank, Prevalence, Salmonella, Smoke-dried fish