Bacteriological quality of raw cow milk at a collection center in Iwo, Osun State, Nigeria

Abstract

Dairy milk provides essential nutrients for humans, but microbial contamination can occur from the point of milking to storage. There has been sparsity of data on quality of raw cow milk (RCM) at collection points in Nigeria. This study investigated the bacteriological quality of RCM from a bulk-tank in Iwo, Osun State, South-West Nigeria. Raw milk samples were collected from the storage tank during a six-week period and evaluated for aerobic plate count (APC), aerobic spore-formers count, Enterobacteriaceae count, salmonella and shigella count and Staphylococcus count. One-way analysis of variance (ANOVA) and Duncan’s multiple range test were used to compare differences in means among the various bacterial counts assessed, using the Statistical Package for Social Sciences (SSPS). The mean aerobic plate count (8.2±1.71 log CFU/ml) and Enterobacteriaceae count (5.8±1.12 log CFU/ml) obtained were significantly different (P≤0.05) and were higher than the acceptable threshold limits of 5.0 log CFU/ml and 3.0 log CFU/ml, respectively. The bacteriological profile found in the milk samples included Enterobacter spp., Salmonella spp., Shigella spp., Staphylococcus spp., and Pseudomonas spp. Enterobacter spp. and Staphylococcus aureus had the highest and least occurrence of 30 % and 2.5 %, respectively. Good sanitary practices are recommended at every stage of the milking process prior to storage in a bulk-tank so as to ensure safe dairy derivative products.