Assessment of coliform bacterial contaminations in raw cow milk from selected dairy farms in Morogoro Municipality, Tanzania

Abstract

Milk quality depends on many parameters including microbial status which mainly originate from the lactating animal itself. Secondary sources of microbial contaminations occur along the milk production chain. Unhygienic harvesting, handling and processing of raw cow milk affect its microbial quality. Microbial contaminations in milk cause spoilage and milk-borne diseases in humans. The current cross-sectional study was conducted to assess the levels of coliform bacterial contaminations in raw cow milk collected from different dairy farms in Morogoro Municipality. A total of 20 farms with lactating dairy cattle were visited and 20 raw cow milk samples were collected for coliform bacteria analysis using standard procedures. East African Standards for coliform count were used to ascertain for raw milk coliform contaminations. Before sampling, some basic information on milking, milk handling, storage and processing were gathered through a questionnaire. It was found that the mean cattle herd size from which the sample was taken was 48 ±8 with mean lactating cows in the herd being 15 ± 28. The general status of coliform bacteria in milk indicated that the contamination rate was 95%. The average total coliform count was 8.1 ± 8.2 (log TCC cfu/ml). The assessed farm activities including type of milking, containers used in milking and storage, occurrences of mastitis and milk storage conditions significantly contributed to coliform bacterial contamination in raw cow milk (p<0.05). It was concluded that almost all the raw cow milk assessed were heavily contaminated with coliform bacteria which implies that either the cows had bacterial infections or there was unhygienic practices in the process of milking, milk handling and storage. This calls for the need of education to the farmers on hygienic way of handling milk along the value chain so as to minimize unnecessary contaminations which can be of public health significance.

Keywords: Raw cow milk, coliforms, Morogoro