Can Your Washing Machine Kill Norovirus?

Norovirus, sometimes called the “stomach flu,” causes nearly 21 million cases of acute gastroenteritis each year in the United States. This highly contagious virus spreads easily from person to person and through contamination of food or surfaces.

Fortunately, norovirus doesn’t live very long outside the body, and basic household cleaners can kill it. But what about using the heat and detergent from a washing machine cycle? Here’s what you need to know about doing laundry when norovirus is around.

How Is Norovirus Transmitted?

Norovirus spreads through contact with contaminated feces or vomit from someone with the infection. Tiny viral particles can end up on an infected person’s hands as well as on surfaces, objects, food, or water. If you touch those contaminated items and then touch your mouth, you may become infected too.

Norovirus is extremely contagious. It only takes a small number of viral particles to make someone sick.

Is Norovirus Heat Resistant?

No, norovirus doesn’t tolerate heat well. Heating foods or liquids above 140°F can kill the virus quickly, sometimes in under one minute. That makes thorough cooking an important way to prevent norovirus from spreading at the dinner table.

Likewise, using very hot water is one of the best ways to kill norovirus on surfaces or fabric items.

How Hot Does a Washing Machine Get?

Washing machines can heat water to the following temperatures:

• Cold wash – under 85°F
• Warm wash – anywhere from 75°F to 110°F
• Hot wash – 120°F to 140°F max for most machines

So you can see that even the hot water setting may not get hot enough to instantly sanitize laundry. However, there are a couple factors that boost a washing machine’s effectiveness against norovirus:

Factors That Help a Washing Machine Kill Norovirus

1. Agitation from Laundry Detergent

The agitation cycle and laundry detergent work together to lift dirt, debris, and microbes away from the fabric. Continuous agitation frees viral particles so they can be rinsed down the drain.

2. Extended Wash Time

A full wash cycle may be 20 minutes or longer. That means norovirus in the wash water is exposed to 120°F to 140°F heat for an extended time.

While quick exposure to 140°F water is best, prolonged exposure to slightly cooler 120°F water can still dramatically cut down on infectious norovirus over time.

So put together, the effects of hot water, detergent formulas, friction, and time inactivate a significant portion of norovirus in contaminated laundry.

How Effective Is a Washing Machine Against Norovirus?

Researchers tested the ability of household laundry procedures to remove norovirus particles that had been sprayed onto seven different types of fabric. After washing, they found:

• A standard warm or hot wash cycle removed over 99% of detectable norovirus from the fabrics.
• Adding bleach or another laundry disinfectant to the wash cycle eliminated 100% of detectable norovirus.
• Dryer heat also helped eliminate more of the virus. Fabrics dried on hot had a 3 log reduction in norovirus compared to fabrics line-dried at room temperature.

So while the wash cycle alone reduces a significant portion of norovirus, the dryer heat helps remove even more.

Best Practices for Laundry and Norovirus

To limit the spread of norovirus through laundry, follow these guidelines:

Handle soiled items carefully: Don’t shake clothing, sheets, or towels that may be contaminated. This can dislodge viral particles into the air. Bag items separately if possible. Disposable gloves are also a good idea.

Wash with detergent on the hottest setting items can stand: For washable fabrics, choose the highest heat setting appropriate for the items. Standard laundry detergent is fine – no need for special disinfectant laundry additives.

Dry thoroughly on high heat: The clothes dryer can provide an additional viral kill step.

Sanitize hampers and washing machines: Use a disinfectant registered to kill norovirus to wipe down hampers and high touch surfaces of the washer. Run the washer through a high heat self-clean or tub sanitize cycle after washing contaminated items.

Keep your distance: Avoid having your face right next to the washer or dryer when handling potentially contaminated laundry. Viral particles could be dislodged into the air.

The Bottom Line

Can a washing machine kill norovirus? Yes – to a significant extent.

Although the wash water may not get hot enough according to strict food safety standards, the cumulative effect of sustained heat exposure, laundry detergent formulas lifting viral particles from fabric, and mechanical agitation can eliminate over 99% of norovirus in contaminated laundry.

Adding the high heat of the clothes dryer removes even more. So running laundry through a complete machine wash and dry cycle is an effective way to sanitize fabric items.

Practice proper handling procedures, move laundry directly from washer to dryer, and wipe down hampers and machines regularly. Following these guidelines will help protect you and prevent norovirus transmission through clean clothes.

References

[1] Center for Disease Control and Prevention. Norovirus Worldwide. Accessed January 2023 at https://www.cdc.gov/norovirus/worldwide.html

[2] Office of Ground Water and Drinking Water. Drinking Water FAQ: Getting the Right Temperature. Accessed January 2023 at https://www.health.state.mn.us/communities/environment/water/factsheet/temp.html

[3] Journal of Applied Microbiology. 2007. Volume 102, Issue 3: Evaluation of a Norovirus Detection Methodology for Soft Fruits and Vegetables. Accessed January 2023 at https://sfamjournals.onlinelibrary.wiley.com/doi/10.1111/j.1365-2672.2006.03155.x

[4] Applied and Environmental Microbiology Journal. 2022. Volume 88 Issue 24: Inactivation of Human Norovirus and Tulane Virus in Laundry. Accessed January 2023 at https://journals.asm.org/doi/10.1128/aem.01649-22