CHARACTERIZATION OF Escherichia coli STRAINS ISOLATED FROM SOME LOCALLY BREWED BEERS IN JOS METROPOLIS

Abstract

This study investigated the microbiological quality of some traditionally brewed and sold beers in Jos, Nigeria. A total of 72 samples, 24 each of mash, wort and beer were collected from six localities namely: Angwan-Rukuba, Gada-Biyu, Tudun-Wada, Ojukwu Street, Kugiya-Bukuru and Jenta Adamu. The different kinds of local beer brands collected from the areas where Moskas, Redcorn, Pito and 9inches. The physico-chemical properties of tap and well waters from the six areas were analysed. The pH and the total titratable acidity of the samples of mash, wort and beer were determined. Samples of raw materials and final products were cultured on various selected media to determine the total bacterial, fungal and faecal coliform. Isolated faecal coliforms were plated on Eosin-Methylene Blue Agar for E.coli identification. Isolates of Escherichia coli were further subjected to rabbit ileal loop assay for enterotoxin production. The result of the physico-chemical parameters of the tap and well waters from these six localities showed only turbidity to exceed acceptable limits, with the highest average value from Jenta Adamu with 10.76 ± 0.21. The pH value of the samples was lowest in the beer samples from Moskas with 4.18 ± 0.15, while the total acidity was highest in Moskas with 0.078 ± 0.0098 mg/L. The average values of bacterial plate counts in all the locations and brands recorded the highest in the mash of the Redcorn with 9.5 x 107. Cfu/ml of Fungi was highest in all beers brands when compared to their mash and wort samples with the highest fungi plate count in the final product of 9inches with 23.3 x 107 cfu/ml. Out of the 36 Escherichia coli assayed for enterotoxin producing attributes only 13 (36.11 %) exhibited fluid inducible capability in animal model. Effective education of food production safety and hygienic handling methods should be encouraged among the local brewers.