Isolation of Listeria monocytogenes from Raw Vegetables and Meats Sold in Open Market in Onitsha Meropolis, Anambra State, Nigeria

Total number of 150 samples comprising of raw-vegetables and raw-meats were obtained from three different markets: Ose market, Ochanja market and Main-market all in Onitsha metropolis, Anambra State, Nigeria. These samples were analyzed bacteriologically for Listeria monocytogenes using a selective and differential media chromagar Listeria. Out of the total number of 150 samples studied, result shows that no Listeria monocytogenes was isolated. Escherichia coli and Staphylococcus aureus were isolated. The result obtained showed that out of 150 samples studied, 39 (26%) were E.coli while 16 (10%) were Staph. aureus. The study shows that Listeria monocytogenes is a very rare cause of endemic illness in the environment. E.coli and Staph. aureus were found to be contaminating vegetables and meats which may have been originated from the soil, water and most especially when food has been handled a great deal and is then left at temperature above refrigeration which allows the bacteria to multiply and produce toxins. This can be prevented by taking adequate measures in handling raw vegetables and meat to avoid any outbreak of diseases caused by E.coli and Staph. aureus as well as listeriosis cause by Listeria monocytogenes, since raw-vegetables and meats are possible contaminants.