Akintunde Dimeji Sharafa
University of Ibadan, Nigeria
Posters & Accepted Abstracts: J Veterinar Sci Techno
Listeria monocytogenes and Staphylococcus aureus are food pathogens that are of zoonotic and economic importance. These organisms are ubiquitous in nature, often found in animal products such as raw milk due to unhygenic practices during milking, handling and transportation of milk. In this study, the levels of microbial contamination (Listeria monocytogenes and Staphylococcus aureus) of fresh bulk milk were determined. A total of 290 and 165 fresh bulk milk samples were collected for the isolation of Listeria monocytogenes and Staphylococcus aureus respectively. Standard bacteriological methods were used to determine the bacterial load, isolate and characterise Listeria monocytogenes and Staphylococcus aureus in fresh bovine bulk milk from dairy herds in Oyo state antibiotics sensitivity of the isolates were determined using disc diffusion method. Bacteriological assay revealed high total mean bacterial counts of 1.5├?┬▒0.069-6.1├?┬▒23.19 log cfu/cm2 while total mean Listeria counts was 1.4├?┬▒0.24-1.9├?┬▒0.13 log cfu/cm2. The overall prevalence of contamination with Listeria species was 10%, upon biochemical characterization, 3.7% were identified as Listeria monocytogenes, 1.1% Listeria innocua and 5.2% Listeria ivanovii L. species isolates showed highest resistance to ceftrazidime (69.3%) and highest sensitivity to gentamicin (92.3%). Out of the 52 coagulase positive S. aureus detected, 13 were found to be methicillin (oxacillin) resistant which gave overall prevalence of 7.9%. Livestock associated methicillin resistant Stapylococcus aureus (MRSA), Staphylococcus aureus isolates showed very high resistance to cloxacillin and highest sensitivity to ofloxacin. The total mean bacterial counts are higher than 2 log cfu/cm2 stipulated by international standard food agencies. The findings in this study indicated that contamination by Listeria in the study area could be attributed to the unhygienic milking procedure. The high S. aureus prevalence of 33.1% signifies higher risk of mastitis in the dairy cow from the study area as well as contamination from the grazing environment, poor herd hygiene, contaminated water, unhygienic milking practices and improperly washed milking bowl. There is need to improve milk quality through proper animal management and health care, prudent use of antibiotics, milk hygiene practices and effective pasteurisation thereby developing sanitation strategies for enhancing the safety of food.
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