Characterization and quantification of bacterial pathogens and indicator organisms in household kitchens with and without the use of a disinfectant cleaner

This two year study evaluated the prevalence of indicator bacteria and specific pathogens in 10 'normal' kitchens in the United States. In Phase I, none of the kitchens was cleaned with an antimicrobial cleaner or disinfectant. Eight locations within the kitchens were monitored for: total heterotrophs, staphylococci, Pseudomonas, total coliforms and faecal coliforms. Almost all locations at all households exhibited contamination, with the sink and sponge samples exhibiting large bacterial concentrations. The faecal coliform concentrations in sink and sponge samples were very high, with 63 and 67% of all samples being positive, respectively. Escherichia coli was detected in 16.7% of all sink surfaces and 33.3% of all sponges. Salmonella was detected once and Campylobacter, on two occasions. In a second phase, households were provided with an antimicrobial disinfectant cleaner which families were encouraged to use but not forced to do so; in some cases, the product was used infrequently or not at all. This regimen did not demonstrate any consistent reduction in the incidence of bacterial contamination. By contrast, in the final phase of the study where disinfectant use was targeted for surfaces soon after contamination with foods or hands, the incidence of contamination decreased dramatically. These data show that normal kitchens can easily be contaminated with a variety of bacterial contaminants including faecal coliforms, E. coli, Salmonella and Campylobacter. Irregular use, or not using antimicrobial agents, is unlikely to reduce the risk of these infectious agents. By contrast, targeted use is likely to reduce the incidence of bacterial contaminants.