ALBUQUERQUE, N.M. (KRQE) –Researchers at the University of New Mexico have determined that exposing masks to dry heat is not an effective way to eliminate the SARS-CoV-2 virus from them. UNM reports that scientists D.J. Perkins, Steven Bradfute, and their colleagues in the Center for Global Health have published a paper in the journal Experimental Biology and Medicine 2021 that found that exposing N95 masks to dry heat temperatures at about 167 degrees Fahrenheit is not an effective way of killing the virus.
According to a press release from the university, Perkins explained that the process would be very beneficial as it’s inexpensive and many hospitals have dry heat ovens. The study comes as many facilities struggled with a shortage of personal protective equipment early in the pandemic and caused many to turn towards disinfection methods as a way to preserve equipment.
To test this method of disinfection, the team of researchers tried several techniques like cutting up masks into small pieces and treating them with a solution that contained various dosages of coronavirus. The masks were then placed on parchment paper or in the wells of plastic tissue culture plates and were then exposed to heat.
UNM reports that the virus was not eliminated in the samples placed on parchment paper however, the dry heat was effective on the mask pieces on the tissue culture plates. According to the researchers, the results suggest that transfer of heat through the material where the N95 samples were placed had a significant impact on the ability to inactivate the virus.
Trying to duplicate an actual decontamination procedure, the researchers suspended intact N95 masks in a heat chamber however, the team reported that after an hour at high temperature, there were still detectable levels of the virus. In another attempt, the team tried to store N95 samples at room temperature for five days and again found that coronavirus remained in some of the samples.
However, the team states that because the virus was eliminated in some of the samples, “it is possible that a longer incubation period (for example 7-10 days) could result in complete inactivation,” said the researchers in the press release.
According to Bradfute, heating masks in a liquid solution is a proven method for disinfection and speculates that the way the viruses disperses within the fibers of a mask may enable some viruses to survive the dry heat treatment. Though the team says the results of the experiment were disappointing, Perkins explains that even reporting the negative results is worthwhile since it contributes to knowledge of the virus.