CONTROL OF LISTERIA-MONOCYTOGENES IN THE DELICATESSEN INDUSTRIES - THE LESSONS OF A LISTERIOSIS OUTBREAK IN FRANCE

During a recent outbreak of foodborne listeriosis which occurred in Fr ance in 1992, investigations were carried out in order to identify the plants associated with the production of contaminated products. These investigations were made in six 'suspect' delicatessen plants followi ng the first epidemiological investigations, and in one 'control plant '. The first visits were made during working operations. Two hundred a nd seventy samples were taken ('environmental' swabs, air samples, pro ducts), with 68% of the swabs being positive for Listeria monocytogene s in raw product areas, and 33% positives in the finished product area . The epidemic phagovar was identified in a single plant preparing por k tongues in aspic.The major causes of contamination identified were c ontact of cooked products with soiled surfaces, cross-contamination be tween 'raw' and 'cooked' channels and the inadequacy of cleaning and d isinfection procedures. A second visit was also made to five plants to provide validation of their cleaning and disinfection procedures. Amo ng 112 swabs collected, 17% of the samples from raw product surfaces a nd 7% from finished product surfaces were found to be positive. These results suggest that cleaning and disinfection procedures were unable to eliminate sources of L. monocytogenes when not correctly applied.