Microbiological and Physichochemical Analysis of Milk Under Solar Powered Cooling System in Siaya County, Kenya

This study aimed to determine the effect of solar powered milk cooling on the microbiological and physicochemical properties of milk. So far, information on impact of solar milk cooling on the microbiological and physicochemical properties of milk remains limited. Samples of uncooled (144) and milk cooled (144) using SPMCS were analyzed for changes in physicochemical and bacterial counts. Clot on boiling, alcohol test and pH were determined as physical components of milk. Chemical composition such as butter fat content, lactose, protein and density were also determined using a lactoscan. Bacterial counts were determined and expressed as colony forming units (cfu). All cooled milk samples were negative for both COB and alcohol test while 12.5 % and 22.2 % of the uncooled milk samples were positive for COB and alcohol test respectively. The pH of cooled (6.63) and uncooled milk (6.4) was significantly different. Similarly, cfu for cooled (5.8 log10 cfu/ml) and uncooled milk (6.4 log10 cfu/ml) samples were significantly different. Negative clot on boiling and alcohol test for cooled milk indicates the effectiveness of SPMCS in preserving milk quality. Slightly higher pH and low bacterial counts of cooled milk was as a result of reduced microbial activity due to low temperatures provided by SPMCS. The system was effective in preserving milk quality on transit thereby lowering losses incurred by farmers.