Microbiological Assessment of Commercial Yogurt Sold in Ota Metropolis, Ogun State, Nigeria.

Abstract

Ten authorized Yogurt products purchased within Ota metropolis, Ogun State of Nigeria were subjected to pH, Total Bacterial Count (TBC) and Total Fungal Count (TFC) analysis. pH values were in the range of 4.05 to 5.50, the TBC and TFC values ranged between 1.0 × 10 3 - 5.0 × 10 5 cfu/ml and 1.0 × 10 3 - 5.0 × 10 5 cfu/ml respectively. Eleven bacterial isolates were detected in the yogurt samples. Lactobacillus spp. and Bacillus spp. constituted 16% of the total microbial load, Corynebacterium spp., Klebsiela spp., Staphylococcus spp., and Pseudomonas spp. constituted 8% while Proteus spp., Micrococcus spp., Shigella spp., Listeria spp., and Streptococcus spp. constituted 4%. Fungal isolates obtained were Mucor spp. (22%), Geotrichum spp. (17%), Montospora spp. (11%), while Aspergillus spp., Rhizopus spp., and Fusanrium spp. constituted 6%.The antimicrobial susceptibility test showed that the isolates exhibited susceptible to Ciprofloxacin and Ofloxacin and resisted Nitrofurantoin, Augumentin, Cefixime, Ceufuroxime, Gentamicin and Ceftazidime. The isolates were plasmid encoded, with size range of 20,000-40,000 Kilo base pairs. Result show no significant difference within the bacteria isolates (P> 0.05), while the fungi isolates showed significant difference (P<0.05). Significant difference also occurred between the bacteria and the fungi isolate (P< 0.05).