Occurrence of Listeria Monocytogenes in Irrigation Water and Vegetables at Jos, Plateau State, Nigeria

Abstract

In this study, thirty water samples obtained from rivers, streams and ponds used for irrigation of vegetables at thirty different sites in Jos, Plateau state, Nigeria were analyzed for the presence Listeria monocytogenes and other Listeria species using the two-step enrichment method. Ten samples each spinach, lettuce and cabbage, which are common vegetables grown in Jos were analyzed for the presence of Listeria monocytogenes. The results obtained showed that out of the 30 water samples screened 10(33.3%) were positive for Listeria monocytogenes. Ponds accounted for 50% of the positive samples, followed by streams (33.3%) and rivers (27.2%). Of the ten samples of vegetables analyzed, only two spinach samples were positive for Listeria monocytogenes. Other bacteria species isolated from the water samples include L. onnocua, L. ivanovii. L. grayi, Bacillus spp, Streptococcus spp, Aeromonas spp, Pseudomonas spp, Klebsiella spp, Escherichia coli and Staphylococcus aureus. Dry season farmers and vegetables handlers in the irrigated fields should be educated on measures aimed at minimizing or eliminating the hazard associated with Listeria monocytogenes.

Keywords: Farmers, vegetables, irrigation waters, bacteria, Listeria monocytogenes