The prevalence of Listeria spp. food contamination in Iran: A systematic review and meta-analysis

Listeria monocytogenes can cause circling disease, encephalitis, meningitis, septicemia, and mastitis in dairy cattle. Contamination from the environment can contaminate foods with Listeria spp. Consumption of foods containing L. monocytogenes can lead to listeriosis in susceptible people (adults with a compromised immune system), pregnant women, and infants. The objective of this study was to determine the prevalence of Listeria spp. and L. monocytogenes in various foods in Iran. We searched PubMed, Science direct, Scopus, Google scholar, and Iranian local databases including Iranian scientific information database and Magiran for relevant studies up to May 2015 using related keywords. In our preliminary search, we retrieved 1344 articles. After removing duplicates and reviewing titles/abstracts, 117 articles were considered, out of which, 75 articles had sufficient quality for inclusion in this meta-analysis. The prevalence of Listeria spp. contamination was about 18.3% in poultry, 8.5% in raw meat, 14.6% in ready-to-eat (RTE) foods, 10% in sea foods, 7.3% in traditional dairy, 3.2% in commercial dairy, and 0.1% in eggs. The findings showed that L. monocytogenes was most prevalent in ready to eat (9.2%), seafood (5.1%), poultry (5%), traditional dairy (4%), raw meat (2.6%), commercial dairy (1.4%), and egg (0.2%), respectively. Furthermore, the presence of L. monocytogenes particularly in RTE foods (that are consumed without further heat processing) and under-cooked products could be a potential risk for public health. So, contamination should be controlled at all levels of the food chain.