By Laura French
CHAMPAIGN, Ill. – A recent study found that electric cookers for households can be used to safely sanitize N95 masks in less than an hour.
Researchers from the University of Illinois, Urbana-Champaign found that 50 minutes of dry heat in an electric cooker, like a rice cooker like Instant Pot, decontaminated N95 respirators inside and out while keeping them filtering and fit, according to a press release from the university.
Researchers found that one 50-minute, 212 F cooking cycle in a dry electric multicooker decontaminates an N95 respirator without compromising filtering or fit. (Photo / Chamteut Oh, University of Illinois, Urbana-Champaign)
Under the leadership of civil and environmental engineering professors Thanh “Helen” Nguyen and Vishal Verma, the researchers published their findings in the journal Environmental Science and Technology Letters.
“There are many different ways to sterilize something, but most will destroy the filtration or fit of an N95 respirator,” Verma said in a statement. “Any sanitation method should decontaminate all surfaces of the respirator, but it is equally important to maintain the filter effectiveness and fit of the respirator on the wearer’s face. Otherwise it will not provide the proper protection. ”
The researchers hypothesized that dry heat could be a method to meet all three criteria – decontamination, filtration, and fit – without requiring special preparation or leaving a chemical residue. They also wanted to find a method that would be widely accessible to people at home. They decided to test an electric cooker, a type of appliance that many people have in their pantries.
They verify that one cycle boils on the preset of the model for rice, which maintains the contents of the cooker for 50 minutes at 212 Fahrenheit, decontaminating the inside and outside masks of four different classes of virus, including a coronavirus – and did so more effectively than ultraviolet light. Then they test the filtration and pass.
“We have built a room in my laboratory for aerosol testing to specifically look at the filtration of the N95 respirators, and measure particles that are passing through,” Verma explained. “The respirators maintain their filter capacity of more than 95% and keep them fit, still well on the wearer’s face, even after 20 cycles of contamination in the electric cooker.”
The researchers made a video demonstrating the method. They note that the heat should be dry hot, with no water added to the cooker, the temperature should be kept at 212 Fahrenheit – or 100 degrees Celsius – for 50 minutes and a small towel should cover the bottom of the cooker around each part of the respirator comes into direct contact with the heating element. However, multiple masks can be stacked to fit in the cooker.
The researchers see potential for the method for electric cakes to be useful for health care workers and first responders, especially those in smaller clinics or hospitals that do not have access to large-scale heat sanitation equipment.
The Environmental Protection Agency and the U.S. Department of Agriculture supported the investigation.
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