Coliform bacteria screening and evaluating chemical composition of raw milkfrom dairy farms of Sylhet Sadar, Bangladesh

Abstract

The study aims screening of coliform bacteria and evaluates chemical constituents of farm supplied raw milk at Sylhet sadar, Bangladesh. A total of 50 milk samples (5 samples from each farm) were collected from randomly selected 10 different farms. Samples were diluted (1:1000000) and bacteria cultures were done in EMB (Eosin methylene blue) agar. Further, Indole test, Methyl red test, Voges-Proskauer were done to differentiate environmental and fecal coliform (Escherichia coli). Chemical analysis of milk was done using automatic milk-analyzer. Total coliform count (TCC) was found to be ranged between 0.6 × 106 to 7.8 × 106 colony forming unit/ml (cfu/ml) and the biochemical tests showed negative results for Indole and Methyl red test and positive for Voges-Proskauer test, respectively confirming the absence of fecal coliform (Escherichia coli) and presence of environmental coliforms. Mean values of Chemical constituents were found to be fat% (4.48%), Solid-Not-Fat% (8.55%), Protein% (3.20%), Lactose% (4.66%) and Mineral% (0.68%). Adulteration with added water in milk was also found with a mean of 0.89%. This study will help to generate an idea about coliform contamination scenario and quality of farm milk found at the particular study area.