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Examination of the microbial status of selected indigenous fermented foods in Nigeria

Olasupo, N.A., Smith, S.I., Akinsinde, K.A.
Journal of food safety 2002 v.22 no.2 pp. 85-93
fermented foods, grain products, food safety, food contamination, microbial contamination, Staphylococcus aureus, Klebsiella, Escherichia coli, Salmonella, Bacillus subtilis, Enterococcus faecalis, plate count, antimicrobial agents, multiple drug resistance, biological resistance, fermented milk, Nigeria
Four Nigerian traditionally fermented foods (wara, nono, ogi and kunun-zaki) were evaluated for the presence of some microorganisms of public health concern. Among the dairy foods, Staphylococcus aureus and Klebsiella sp. were isolated from wara while Escherichia coli, Salmonella sp. and Klebsiella sp. were isolated from nono. The cereal-based fermented foods (ogi and kunu-zaki) contained Bacillus subtilis, E. coli, S. aureus, Klebsiella sp. and Enterococcus faecalis. The mesophilic aerobic counts were: 5 x 10(5) for wara; nono, 1.53 x 10(7); ogi, 3.6 x 10(6) and kunu-zaki, 2.6 x 10(6) cfu/mL. The enterobacteriaceae counts on nono, wara, ogi and kunu-zaki were 1.79 x 10(7), 4.5 x 10(5), 4.0 x 10(5) and 1.2 x 10(6) cfu/mL, respectively. No Vibrio count (detection limit: < 10 cfu/mL) was recorded in all the food samples considered. The yeast and mold counts ranged from 1.0 x 10(5)-3.31 x 10(7) among the food products. The antimicrobial susceptibility patterns of the organisms isolated from dairy products (nono and wara) revealed that they were resistant to ampicillin (100%) and sensitive to gentamicin (100%) and nalidixic acid (100%). Most isolates from cereal based products (ogi and kunu-zaki) were 100% resistant to penicillin, ampicillin and chloramphenicol. This work highlights the need to maintain hygienic standards in the preparation of our locally fermented cereal and dairy foods.