Effect of milking time and handling techniques on microbial quality and exposure assessment of cow’s fresh milk consumption in Lilongwe, Malawi

Abstract

Fresh cow milk is both a source of food nutrients and income to humans. However, if improperly handled at milking stage, it can be a source of bacterial pathogens which threaten health of human beings. This study investigated the effect of milking time and handling techniques on microbial quality and exposure assessment of consumption, using 52 fresh cow milk and corresponding water samples at the LUANAR-NRC dairy farm. Total bacterial count (TBC) was used as an indicator of the microbial quality of the milk, normalized by log-transformation and expressed in coliform plate counts (CFU/ml) as means ± standard deviations. One-way ANOVA was used to identify and assess the possible predictors of TBC. A cross-sectional survey of consumers around the farm was conducted to assess exposure effect at raw consumption. The major bacterial isolates from the milk samples were Staphylococcus Spp. (38%) and E. coli (34%). Consistent with records of below standard pH values (6.072 ± .0285), morning milk samples registered higher mean bacterial counts (6.0867±1.9334 log CFU/ml) than the afternoon (2.2001±2.8732 log CFU/ml) batch. Furthermore, milking time and handling techniques, combined, significantly (p < 0.05) contributed to the presence of bacteria. Unlike milk handling (p > 0.05), milking time alone significantly contributed (p < 0.01) to the high proportions of bacterial counts. The significant effect of both milking time and handling on raw cow’s milk microbial quality calls for immediate actions along the dairy value chain to prevent the spread of foodborne diseases caused by bacterial hazards.