Prevalence of Listeria monocytogenes in Fresh and Raw Fish, Chicken and Beef

Abstract

There has been recent outbreaks of food poisoning associated with Listeria monocytogenes. Most of the outbreaks were attributed to fresh meat and dairy products, and processed foods. This study was therefore carried out to examine the prevalence of Listeria monocytogenes in fish, beef & chicken sold in area markets in Calabar. A total of two hundred and fifty five (255) samples; fresh raw fish, chicken and beef were obtained from six different markets and were analyzed for possible contamination with Listeria monocytogenes using compact Dry LS plate. Out of the two hundred and fifty five (255) samples analysed, the results obtained showed one hundred and sixty two (63.5%) were positive. Beef showed a prevalence rate of 88% while chicken and fish showed prevalence rates of 64.7% and 37.7% respectively. The highest bacterial count was recorded in beef (7.2x103 cfu/g) and lowest in fish (1.08 x 102 cfu/g). The market locations also played a role as the Akim market beef showed the highest load followed by Goldie market and Mayne avenue market.        The frequency of occurrence of L. monocytogenes was highest for Watt market with 73.8% followed by Uwanse market with 71.4%. The least occurrence was Marian market. The L. monocytogenes counts (cfu/g) according to locations for beef, chicken and fish showed significance (p < 0.05). However, comparison of the counts beef with chicken, beef with fish, and chicken with fish did not show any significance (p > 0.05). The occurrence and safety challenge of this organism in foods as well as the high mortality rate associated with listeriosis have made the pathogen a serious public health concern. For the fact that L. monocytogenes was isolated from these meat products is of serious concern to the health of consumers of these meats. Documentation of food borne disease outbreaks and the causative agents is therefore necessary.