The microbiological quality of washing-up water and the environment in domestic and commercial kitchens.

Abstract

To determine the microbiological quality of washing-up water and the environment in domestic and commercial kitchens. Chicken meals were prepared by people without food safety training in their own kitchen (n = 52) or by trained staff in a commercial kitchen (n = 10). Study participants then washed-up, cleaned the kitchen and completed a food hygiene questionnaire. The temperature and microbiological quality of the washing-up water, and the presence of pathogens in dishcloths, tea towels and other kitchen samples was determined. Of the raw chickens used in meal preparation, 96 and 13% were naturally contaminated with Campylobacter or Salmonella spp., respectively. In domestic kitchens, two of 45 sponges, dishcloths or scourers and one of 32 hand- or tea towels were contaminated with Campylobacter after washing-up and cleaning but none of the tap or sink swabs yielded pathogens. The mean washing-up water temperature in the domestic kitchens was 40.7 degrees C, whereas in the commercial kitchen it was 44.7 degrees C (P = 0.04). Study participants who used hotter water (>/=40 degrees C) had lower levels of bacteria in their washing-up water. The aerobic plate counts of the washing-up water samples in domestic homes were usually between 105 and 106 CFU ml-1 but those associated with the commercial kitchen were consistently lower (P = 0.01). Despite this, Campylobacter was detected in one of 10 washing-up water samples from the commercial kitchen but in none of the samples from domestic kitchens. Pathogenic microorganisms can be recovered relatively frequently from the kitchen environment. By identifying factors that affect the number of microorganisms in washing-up water and the kitchen environment, evidence-based recommendations on implementing domestic food hygiene can be made.