Monitoring of contamination sources of Listeria monocytogenes in a poultry slaughterhouse

- L. monocytogenes is an actual problem in poultry slaughter plants.
- The automated cutting process is a major contamination sources.
- The operational cleaning with hot water is not efficient.

This study evaluated the incidence and identify the Listeria monocytogenes potential contamination in a poultry slaughter plant and assessed the effectiveness of the sanitation process used by the company. A total of 920 breast and 774 thigh samples were analyzed, and L. monocytogenes was found in 8.64 and 44.19% of the samples, respectively. The thigh samples presented more contamination than the breast, throughout the study. The third work shift showed the highest thigh contamination (51%). The contamination percentage was lowest in summer and greater in winter. L. monocytogenes contamination in whole carcasses was absent in samples collected before the chilling process, while 5% of the samples were contaminated after this process. After the automated cutting process, the L. monocytogenes contamination percentage increased linearly, reaching 25 and 70% after 5 h for breast and thighs, respectively. The percentage of contamination on the equipment and utensils used on thigh samples was high during the processing (86.67%) and after the cleaning operation (66.87%). After pre-operational sanitation of equipment and utensils a lower incidence of L. monocytogenes in the production line was observed.