Total aerobic and Coliform counts from <I>Oreochromis niloticus</I> obtained from selected farms in Ibadan

Abstract

The environment where fishes are caught often determines their microbial flora, many of which are potential spoilers and not necessarily pathogenic to fishes but are implicated as cause(s) of serious foodborne illnesses and toxin-infections in humans, hence, their presence above permissible levels portends food-safety threats. This study showed the microbial load in Oreochromis niloticus obtained from selected farms in Ibadan, Nigeria. A total of 156 samples consisting of gills, intestines and skins were collected from 52 O. niloticus obtained from Egbeda-(A), Ido-(B), Ibadan-north east-(C) and Ibadan north-west-(D) Local Government Areas of Ibadan for Microbial Load {Total Aerobic Count-(TAC) and Total Coliform Count-(TCC)} enumeration. TAC and TCC were performed using standard methods, and  calculated in mean Log Colony Forming Unit ± Standard Deviation (logCFu ± SD). Data were analysed with ANOVA. Overall mean logCFu ± SD TAC and TCC from gills, intestine and skin for the 156 samples were 8.65 ± 0.28 and 6.82 ± 0.20, respectively. Mean TAC 8.64 ± 0.28, 8.69 ± 0.28and 8.62 ± 0.3 and mean TCC 8.69 ± 0.22, 8.66 ± 0.23 and 8.73 ± 0.22 were obtained for gills, intestine and, skin respectively, with p>0.05. Means TAC 8.63 ± 0.36, 8.70 ± 0.20, 8.68 ± 0.33 and 8.56 ± 0.14 and TCC 8.56 ± 0.25, 8.86±0.16, 8.65 ± 0.18and 8.69 ± 0.16 were observed for locations A, B, C, and D respectively with p<0.05 for TAC and p˂0.05. Mean microbial load counts obtained in this study was higher than permissible count of 7 logCFu/mL by International Commission on Microbiological Specification for Foods (ICMSF) for fresh fish, thus, portending public health threats.

Keywords: Oreochromis niloticus, Aerobic bacteria, Enterobacteriacea and Coliforms