Raw cattle milk quality from smallholder dairy farms with respect to E. coli and Salmonella quality indicators

The study examined the quality of raw cattle milk produced by smallholder farmers from selected districts in central Uganda. Two major “quality indicators”, i.e., presence of Salmonella spp. and Escherichia coli were considered. The colony forming units for Salmonella spp. and E. coli were established following the standard plate count method. Absolute certainty was achieved by subjecting sample isolates to Gram staining. Milk samples were purposively collected at the respective milking times and tested in a laboratory using serial dilutions of 10,000 and 100,000 mls for E. coli and Salmonella spp., respectively. Analysis was done using the pour plate method on McConkey and dulcitol selenite agar media for E. coli and Salmonella spp., respectively. Plates were incubated at 35oC and data collected after 48 hours. There was a strong positive correlation (r = 0.9) between experimental data and national standards for both Salmonella and E. coli. The t-test results (P=0.05) for Salmonella (P=0.301) and E. coli (P=0.1206) were not significantly different for different raw milk handling levels. Therefore, Salmonella and E. coli exist in smallholder farmers’ raw milk in variable quantities, though not significant to affect the quality of milk. Routine milker training and assigning responsibilities for all areas of prevention of contamination on smallholder farms is a recommended practice. Periodic milk examination to provide microbiological count records on the prevalence of E. coli and Salmonella spp. at different milk handling chains is a practice that is recommended to all milk handlers.