Prevalence of Listeria spp. in ready to eat foods (RTE) from Algiers (Algeria)

The aim of this study was to establish the occurrence of Listeria spp., especially Listeria monocytogenes in ready to eat RTE food marketed in Algiers (Algeria). A total of 227 samples were collected from different producers and retailers. All samples were analyzed using a conventional cultivation method AFNOR V08-055. Out of 227 samples tested, 21 (9.3%) tested positive for Listeria spp. among them, 6 (2.6%) tested positive for L. monocytogenes. L. innocua was the most common Listeria species found being detected in 11 samples (4.8%), although both Listeria ivanovii and Listeria welshimeri were detected in 3 (1.3%) and 1 (0.4%) food samples respectively. The study of the antimicrobial sensitivity of Listeria monocytogenes strains showed no resistance. The study has enabled us to detect these contaminants in a wide range of RTE foods, to suggest that contamination likely occurs after heat treatment, and to assess the danger represented by this category of food for populations at risk.