P-47 Bacterial Analysis of Raw Cow’s Milk Sold in Region 5, Guyana

Methods: This observational study investigated 20 samples of raw cow’s milk. The samples were investigated using the standard plate count method to ascertain the total viable count on nutrient agar using serial dilutions. The identification of specific bacteria was determined using the spread plate and streak plate methods on various selective media such as Mac Conkey (MAC) agar, Salmonella and Shigella (SS) agar,Xylose Lysine Deoxycholate (XLD) agar, Eosin Methylene Blue (EMB) Agar and CHROMagarTM Salmonella. Salmonella spp. was also identified using biochemical media such as Triple sugar iron agar (TSA), Sulfide indole motility (SIM), urease, and citrate. The data were presented as average cfu/ml and numbers (%) of positive samples.

Results: The average bacterial load was found to be 1.1 x 106 cfu/ml. The highest count was noted for Sample 2 (3.6 x 106 cfu/ml) and the least was noted for Sample 18 (1.5 x 104 cfu/ml). Thirteen samples (65%) had a bacterial load above the regulatory standard for raw cow’s milk (1 x 105 cfu/ml). The occurrence of Salmonella spp., E. coli, and other coliforms was 20%, 25%, and 65%, respectively. Fourteen samples (70%) tested positive for at least one type of bacteria.

Conclusion: This study revealed bacterial contamination above the regulatory standard for raw cow’s milk, and the presence of E. coli and other Coliforms, and Salmonella spp., in many of the raw cow’s milk sold by farmers in Region 5, Guyana. We recommend strict education and training protocols for farmers and consumers about milking hygiene and sanitation practices. Screening for mastitis in dairy cows should be made mandatory