Prevalence and Public Health Implications of Isolation of Listeria monocytogenes from Fresh Raw Milk Sold in Ilorin, Nigeria

Abstract

Introduction: Milk is a nutritious fluid secreted by female mammals to nourish their young. Milk-borne pathogens remain a major public health concern in Nigeria, where raw cow milk is widely consumed without pasteurization. This study was conducted to determine the prevalence of Listeria monocytogenes and other potential pathogens in raw cow milk sold in Ilorin, Kwara State, Nigeria.

Methods: A total of 240 raw milk samples were randomly collected from vendors across three major markets in Ilorin. The samples were analyzed using standard microbiological techniques involving culture on Listeria-specific selective medium and biochemical identification tests.

Results: Out of the 240 samples examined, 28 (11.7%) were positive for Listeria spp. presumptive L. monocytogenes. Other potential bacterial pathogens isolated were Staphylococcus aureus and Escherichia coli. The association between sample source and the presence of L. monocytogenes was not statistically significant (p = 0.851), suggesting that contamination was widespread across different milk sources rather than limited to specific locations. The health implications of these findings are considerable, as listeriosis can result in septicemia, meningitis, miscarriage, stillbirth, particularly in pregnant women, neonates and the elderly. These findings underscore critical gaps in milk hygiene, storage, and food safety surveillance in Nigeria.

Conclusion: The presence of Listeria spp. presumptive L. monocytogenes and other potential pathogens in raw cow milk sold in Ilorin highlight a possible serious health hazard to citizens consuming this product and a pressing public health concern that requires immediate attention.