Bacteriological Quality of Commercially Sold Yoghurt in Calabar Municipality , Cross River State , Nigeria

Background: Yoghurt production involves the fermentation of the lactose content of milk to yield lactic acid, CO2, acetic acid, diacetyl, acetaldehyde, amongst others, using Streptococcus thermophilus and Lactobacillus bulgaricus. Fermenting organisms produce lactase, which hydrolyzes lactose to simple sugars, glucose and galactose, making it more accessible to lactose-intolerant patients.The increased awareness of the benefits of constant yoghurt consumption has increased the rate of yoghurt consumption in Calabar and Nigeria as a whole, leading to the establishment of many small-scale factories for yoghurt production. Many unqualified people whose products lack certification by the appropriate agencies have also moved in for the sole purpose of making money. The purpose of this study was to assess the bacteriological quality of yoghurt sold in Calabar Municipality,to determine whether or not they are free from harmful bacteria, to identify the pathogens and determine the microbial load therein. Method:Ten different brands of sachet packaged yoghurt were obtained fromvarious sales outlets in Calabar Municipality. Two samples of each brand were used and properly labeled giving a total of 20 yoghurt samples. Representative portions of the yoghurt samples were placed into sterile universal containers.Serial dilution was done and samples were cultured using the spread plate method on Cysteine Lactose Electrolyte Deficient, Chocolate and Blood Agar platesfor colony counts. Standard bacteriological and biochemical tests were used to identify isolates. Results:The pH values of the yoghurt samples ranged between 2.35 and 3.26. One out of the 10 brands had no visible bacterial growth while the other brands had growth. The bacteria isolated from the yoghurt included Klebsiella sp., Streptococcus sp., Bacillus sp., Escherichia coli and Staphylococcus aureus. S. aureus had the highest frequency of 70% followed byKlebsiella sp. with a frequency of 60%, Bacillus sp. 50%, Escherichia coli 40% and Streptococci 20%. Conclusion: Considering the frequencies of occurrence above, it is evident that these products are potential health hazards. Hence, the agencies responsible for ensuring food safety should put in more effort in ensuring that good manufacturing practices (GMP) are employed and ininspecting commercially sold yoghurt before they get to the consumers.