MICROBIAL LOAD IN LOCAL AND IMPORTED RAW MILK

Abstract

There was a complaint on supplying low quality milk to residents of Samdrup Jongkhar. This study was carried out in winter to evaluate and compare the milk quality from two main sources. The emphasis was given more on assessing the microbial load in raw milk for both local and imported milk. Samples from individual cans (N=35) and bulk tank (N=7) were collected for imported and local milk. A volume of 50 ml milk sample was collected aseptically in a 50 ml vial. The sample was transported to laboratory at 2- 8⁰C, packed in cool box with ice packs. The microbial load in milk was estimated using Pour Plate Technique at 30±2⁰C at 72 hours. The microbial load was calculated in cfu ml-1 . All microbial counts were converted to the base 10 logarithm of the number of colony forming units per ml of milk samples (log cfu ml-1 ). T-test was conducted to compare the microbial loads between imported and local milk. The microbial load was significantly higher in imported milk (M=8.54±0.06) when compared with local milk (M=8.39±0.03). The mean values of microbial load for imported (N=35) and local milk (N=35) were 8.54 log10 cfu ml-1 and 8.39 log10 cfu ml-1 , respectively. The mean microbial load for both imported and local milk exceeded the EU and US standard. The mean microbial load for bulk tank samples was higher, compared with individual can samples from both sources. Timely monitoring of milk at producer’s level, milkman and sales counter are necessary to minimize contamination of milk.