Hygiene measures considering actual distributions of microorganisms in Japanese households

Aims: Effective household hygiene measures require that sources of bacterial contamination and the places to which contamination spreads be carefully identified. Therefore, a study was performed to examine the distribution of microorganisms throughout ordinary households in Japan, which has its own unique customs of daily life and food preparation. Methods and Results: Using the stamping method, samples were taken from 100 different places and items in each of 86 households. This study found kitchens/dining rooms to have the greatest level of microbial contamination and bathrooms, the next highest level. Toilets (water closets) were found to have an unexpectedly low level of bacterial contamination. The largest bacterial counts were found on items such as drain traps, dish-washing sponges, counter towels, sinks, dish-washing tubs, and bathroom sponges. Conclusions: It is necessary to carefully identify both the items that can become instruments for spreading bacterial contamination and the places that easily become subject to secondary contamination, and then to take timely and effective disinfection/sanitizing measures. Significance and Impact of the Study: The data gathered in this study will be very valuable for anticipating the pathways over which bacteria are transported and prioritizing disinfection targets, to make effective disinfection possible.