Department of Health Science, Kitasato University School of Allied Health Sciences.
Department of Environmental and Occupational Health, School of Medicine, Toho University.
Biocontrol Sci. 2022;27(3):153-162. doi: 10.4265/bio.27.153.
Bidet-toilets are widely used in households and public spaces in Japan. The effect of nozzle cleanliness on spray water quality of warm-water bidet toilet seats is unknown. We conducted a long-term experimental model-based study (2015-2016) and two survey-based studies (A: 2018-2019 and B: 2020-2021) at a university campus. Survey A measured the effect of nozzle cleansing on total viable count (TVC) and heterotrophic plate counts (HPCs) in spray water. Survey B measured the total organic carbon, residual chlorine concentration, TVC, and HPC of different fractions of sprayed water. We found no upstream migration of microbes from the nozzle to water tanks. While daily cleaning of the nozzle surface could reduce bacterial count in spray water, continuous discharge of water washed away bacterial contamination. Fecal indicator bacteria were in traces in spray water, indicating proper maintenance of these toilet seats.
在日本，家庭和公共场所广泛使用坐浴盆。喷嘴清洁度对温水坐浴座便器喷水水质的影响尚不清楚。我们在大学校园进行了一项基于长期实验模型的研究（2015-2016 年）和两项基于调查的研究（A：2018-2019 年和 B：2020-2021 年）。调查 A 测量了喷嘴清洁度对喷雾水中总活菌数（TVC）和异养平板计数（HPC）的影响。调查 B 测量了不同喷雾水部分的总有机碳、余氯浓度、TVC 和 HPC。我们没有发现微生物从喷嘴向上游迁移到水箱。虽然每天清洁喷嘴表面可以减少喷雾水中的细菌数量，但连续排放的水会冲走细菌污染。喷雾水中痕量存在粪便指示菌，表明这些马桶座圈得到了适当的维护。
