Prevalence of Listeria spp. on the Hands of Food Workers

The prevalence of carriage of Listeria spp. on the hands of food workers was investigated using a whole-hand impression plate technique. Ninety-nine workers engaged in food production and retailing were studied, with 75 clerical workers acting as control. Twelve (12%) of food workers carried Listeria spp., and 7 (7%) carried Listeria monocytogenes . None of the control group was positive for Listeria spp. Where the level of carriage was low (<20 CFU) hand washing eliminated the organisms, but hand washing was not successful if larger numbers of bacteria were present. In two instances hand washing appeared to have caused contamination of subjects' hands. Food workers are significantly more likely to carry Listeria spp. than clerical workers (P < 0.015 Fisher's exact test) and frequent hand washing represents an important element of hygiene which may interrupt transmission of these organisms.