Microbial Assessment and Microbiological Quality of Some Commercially Prepared Yoghurt Retailed in Ibadan, Oyo State, Southwestern Nigeria

Yogurts are ready to drink foods commonly taken for energy production and for health in Nigeria but there is paucity of studies done to evaluate their food safety. Therefore this study was carried out to determine the microflora of some available yogurts sold in Ibadan. Twenty types of commercially prepared yogurt products were purchased, from Ibadan in Oyo State, Nigeria and its’ environs, transported, processed and analyzed using standard laboratory methods. A total of 25 different organisms were isolated from 20 yogurt samples with Lactobacillus bulgaricus, Streptococcus lactis and Saccharomyces cerevisiae each being the most frequently isolated with frequency of 16.0%. They were also tested to show if their pH production was lactosedependent. There were significant decline in pH in tryptone soy broth (t = -13.88, p<0.05), peptone with lactose (t = -16.61, p<0.05), and peptone containing milk and lactose (t = -10.41, p<0.05). This study has shown that most yogurts in Ibadan contain probiotics isolates including L. bulgaricus, S. lactis and S. cerevisiae, which are therefore, beneficial for human consumption.