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The goal of good toilet hygiene is minimizing the potential for pathogen transmission. Control of odours is also socially important and believed to be a societal measure of cleanliness. Understanding the need for good cleaning and disinfecting is even more important today considering the potential spread of emerging pathogens such as SARS-CoV-2 virus. While the flush toilet was a major advancement in achieving these objectives, exposure to pathogens can occur from failure to clean and disinfect areas within a restroom, as well as poor hand hygiene. The build-up of biofilm within a toilet bowl/urinal including sink can result in the persistence of pathogens and odours. During flushing, pathogens can be ejected from the toilet bowl/urinal/sink and be transmitted by inhalation and contaminated fomites. Use of automatic toilet bowl cleaners can reduce the number of microorganisms ejected during a flush. Salmonella bacteria can colonize the underside of the rim of toilets and persist up to 50 days. Pathogenic enteric bacteria appear in greater numbers in the biofilm found in toilets than in the water. Source tracking of bacteria in homes has demonstrated that during cleaning enteric bacteria are transferred from the toilet to the bathroom sinks and that these same bacteria colonize cleaning tools used in the restroom. Quantitative microbial risk assessment has shown that significant risks exist from both aerosols and fomites in restrooms. Cleaning with soaps and detergents without the use of disinfectants in public restrooms may spread bacteria and viruses throughout the restroom. Odours in restrooms are largely controlled by ventilation and flushing volume in toilet/ urinals. However, this results in increased energy and water usage. Contamination of both the air and surfaces in restrooms is well documented. Better quantification of the risks of infection are needed as this will help determine what interventions will minimize these risks.

Laundering of textiles – clothing, linens, cleaning cloths - functionally removes dirt and bodily fluids which, prevent the transmission and re-exposure to pathogens as well as odor control. Thus, proper laundering is key to controlling microbes that cause illness and produce odors. The practice of laundering varies from region to region and is influenced by culture and resources. This review aims to define laundering as a series of steps that influence the exposure of the person processing the laundry to pathogens – with respect to the removal and control of pathogens and odor causing bacteria, while taking into consideration the types of textiles. Defining laundering in this manner will help better educate the consumer, highlight areas where more research is needed, and how to maximize products and resources. Control of microorganisms during laundering involves mechanical (agitation, soaking), chemical (detergent, bleach), and physical processes (detergent, temperature). Temperature plays the most important role in terms of pathogen control, requiring temperatures exceeding 40°C to 60°C for proper inactivation. While detergents play a role in reducing the microbial load of laundering through release of microbes attached to fabrics and inactivation of microbes sensitive to detergents (e.g. enveloped viruses). The use of additives (enzymes) and bleach (chlorine, activated oxygen) become essential in washes with temperatures below 20°C, especially for certain enteric viruses and bacteria. A structured approach is needed which identifies all the steps in the laundering process and attempts to identify each step relative to its importance to infection risk and odor production.

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Aims:The aim of this study was to determine how the transfer efficiency of MS-2 coliphage from the toilet seat to hands and fingertip to lip differs according to the suspension of the inoculum. Methods and Results:Hands were sampled after lifting a toilet seat which was inoculated with MS-2 on the underneath side. MS-2 was suspended in a spectrum of proteinaceous and non-proteinaceous solutions. Transfer efficiencies were greatest with the ASTM tripartite soil load (3.02% ± 4.03) and lowest with phosphate-buffered saline (PBS)(1.10% ± 0.81) for hand-to-toilet seat contacts. Finger-to-lip transfer rates were significantly different (p < 0.05) depending on suspension matrix, with PBS yielding the highest transfer (52.53% ± 4.48%) and tryptose soy broth (TSB) the lowest (23.15% ± 24.27%).Quantitative microbial risk assessment was used to estimate the probability of infection from adenovirus and norovirus from finger contact with a toilet seat. Conclusions:The greatest transfer as well as the largest variation of transfer were measured for finger-to-lip contacts as opposed to toilet seat-to-finger contacts. These factors influence the estimation of the probability of infection from micro-activity, that is, toilet seat adjustment.

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Wastewater treatment plants (WWTPs) have rapidly increased in India during the last decade. Nonetheless, there are only a few labs in India that can perform culture-based screening for microbial quality.

K.A. Reynolds was funded through an interagency personnel agreement with NIOSH. The findings and conclusions in this document are those of the authors and do not necessarily represent the official position of NIOSH.