We’re now in the second year of the pandemic, and it is still unclear how likely SARS-CoV-2 can be transmitted through the clothes we wear. Let’s review what we know so far and how laundry industry professionals should handle and wash soiled clothes properly as we continue to combat the virus.
How long can Sars-CoV-2 survive on surfaces?
We know that the best way for COVID-19 to be transmitted is through aerosols which we can potentially inhale. Large droplets stay from seconds to minutes, while small droplets can get suspended for minutes up to hours, according to the U.S. Centers for Disease Control and Prevention.
In a review of 14 kinds of materials, this research on the Egyptian Journal of Basic & Applied Sciences identified paper as having the lowest duration of persistence for the virus (30 minutes) and complete decay (3 hours). The virus can persist on cardboard, banknotes, and wood for a day; glass, 2 days; stainless steel and plastic, 3-4 days; fecal matter, 3 days; surgical mask, 4 days; and smooth surfaces for 7 days.
How about for fabrics? Like paper, the virus’ duration of persistence is 1 day and will completely decay in 2 days, according to this research from The University of Hong Kong’s School of Public Health. (The 24-hour survival rate is consistent with an earlier research on The New England Journal of Medicine.)
Another study suggests that the coronavirus can lurk for a long time in some types of fabric. Scientists from De Montfort University Leicester found that the coronavirus can survive in polyester for up to 3 days. In pure cotton, the said virus survives for 24 hours, while in polycotton, it is only 6 hours. I should note that the scientists did not use Sars-CoV-2, instead they sampled HCoV-OC43, which has similar characteristics and patterns with Sars-CoV-2.
What factors affect Sars-CoV-2 survival?
Why do influenza-type viruses survive less in clothes versus other materials? Science suggests it has to do with porosity. Glass, stainless steel, and plastic are impermeable materials, whereas cardboard (which we use in our deliveries), paper, and fabric are porous. In impermeable materials, a thin liquid film remains after a droplet evaporates – one that can explain longer virus survival, according to researchers from the Indian Institute of Technology Bombay, published on the Physics of Liquids. Materials that accelerate evaporation is less favorable for the virus.
How can you protect your laundry customers?
Although many things are still unclear, the commercial laundry industry has an important role to play in decreasing the risk of contamination and transmission. Those catering to institutions such as hospitals, hotels, F&B, pharmaceuticals, semi-conductor, food processing, and manufacturing, in particular, follow best practices.
Key to ensuring our laundry customers get the best form of COVID-safe service is to understand the difference between cleaning, sanitizing, and disinfection.
The Centers for Disease Control and Prevention describe the difference this way:
- Cleaning – Removal of germs, dirt and impurities from objects
- Sanitizing – Reduction of germs to a safe level
- Disinfecting – Killing germs, enabling a lower risk of spreading infection
If you have attended any of my past webinars on the science of laundry, remember the wash process and try to imagine applying these modifications to the standard commercial practice:
- In the pick-up process, the laundry team must wear proper protective equipment, especially when catering high-risk facilities. Disinfectant must be pre-sprayed and packing must be done quickly.
- Sorting should be done in places with good air flow, with the sorter dressed in protective equipment.
- During weighing, you can underload depending on the fabric. Polyester requires more mechanical action (remember the Sinner Circle), therefore I recommend to underload and just use 66% of the washer’s capacity.
- In the soaking process, sinks should be loaded with both water detergent and disinfectants. Soak all stained items to reduce manual stain removals.
- Use hot wash so detergents can work better and to kill the virus. (De Montfort University Leicester research shows that the virus is stable at 60 degrees Celsius, but inactivated at 67 degrees Celsius.)
- You must apply both fabric conditioner / fabric softener and disinfectant on the last rinse.
- Don’t forget to test for excess alkalinity. Apply fabric conditioner and disinfectant again if the result is not favorable.
- Ensure disinfection on equipment such as flatwork ironing, spotting, pre-drying, drying, folding, and packaging.
- Avoid the formation of moisture after packaging. This will lead to mildew on newly laundered garments. (Learn here how to prevent molds and mildew.)
The key to good wash and disinfection that addresses the COVID-19 challenge is a wash process with a good rinse. While Sars-Cov-2 can be deactivated with a good wash process (hot water and detergent), it is prudent to apply pro-active measures such as using quaternary disinfectants to make sure that the succeeding process (rinsing) and its ingredients (new water) will not contaminate and compromise the laundered products.
Applying the principle of cleaning, sanitizing, and disinfecting will ensure that products of the laundry process are safe and virus-free, therefore winning back the confidence from worried customers.
If you want to learn more about the laundry business in the time of COVID-19, sign up in my upcoming virtual masterclass: Unlocking the Science of Cleaning & Sanitation: Principles, Business Application & Adapting in a COVID-19 World on October 9 and October 23, both Saturdays at 2-5 pm GMT+8. Sign up here
Helpful links about COVID-19
World Health Organization: Cleaning & disinfecting environmental surfaces in the context of COVID-19: here
World Health Organization: Water, sanitation, hygiene, and waste management for Sars-CoV-2: here
Department of Health (Philippines): Guidelines on cleaning and disinfection: here
Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1. The New England Journal of Medicine 2020; 382:1564-1567. DOI: 10.1056/NEJMc2004973
Centers for Disease Control and Prevention. (6 May 2021). How To Clean and Disinfect Schools To Help Slow the Spread of Flu. https://www.cdc.gov/flu/school/cleaning.htm
Centers for Disease Control and Prevention. (7 May 2021). Scientific Brief: SARS-CoV-2 Transmission. https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/sars-cov-2-transmission.html
Chin, Alex & Chu, Julie & Perera, Ranawaka A.P.M & Hui, Kenrie & Yen, Hui-Ling & Chan, Michael & Peiris, Joseph S & Poon, Leo. (2020). Stability of SARS-CoV-2 in different environmental conditions. 10.1101/2020.03.15.20036673.
Owen L, Shivkumar M, Laird K. 2021. The stability of model human coronaviruses on textiles in the environment and during health care laundering. mSphere 6:e00316-21. https://doi.org/10.1128/mSphere.00316-21.
Ranjan K. Mohapatra, Pradeep Kumar Das, Lucia Pintilie & Kuldeep Dhama (2021) Infection capability of SARS-CoV-2 on different surfaces, Egyptian Journal of Basic and Applied Sciences, 8:1, 75-80, DOI: 10.1080/2314808X.2021.1907915
Sanghamitro Chatterjee, Janani Srree Murallidharan, Amit Agrawal, and Rajneesh Bhardwaj (2021). Why coronavirus survives longer on impermeable than porous surfaces. Physics of Fluids 33, 021701 (2021) https://doi.org/10.1063/5.0037924