Process environment sampling can help to reduce the occurrence of Listeria monocytogenes in food processing facilities

Abstract

The occurrence and persistence of Listeria monocytogenes strains in food processing environments pose a risk of cross-contamination to food. The control of these strains is thus essential to ensure food safety. In the present study, 205 samples were collected from a food processing facility between May 2012 to February 2013 and analysed for the presence of L. monocytogenes by the ISO11290 standard method. L. monocytogenes isolates were differentiated using pulsed field gel electrophoresis. Up to 55% of the samples were positive for L. monocytogenes until October 2012. Advice was given on the implementation of corrective actions regarding cleaning and disinfection procedures and workflows. This resulted in a decrease in the number of positive samples, reflecting the reduction of L. monocytogenes in the processing environment. Eight pulsotypes were found in the food processing facility environment, mainly on non-food contact surfaces. One type was identified as persistent as it was isolated on each sampling occasion and constituted more than 71% of the isolates collected. It was the only type found in the processing environment after the implementation of corrective actions. This work demonstrates that processing environment sampling plans are effective to assess hygiene and implement corrective actions. This contributes to prevention of contamination events and consequently to assuring the safety of the food product.