The viral load that causes COVID-19 can be inactivated indoors and outdoors at 56°C for 52 minutes, or at 65°C for 7 1/2 minutes. This is reflected in a study by the Institute of Agricultural Food Research and Technology, which proposes that thermal disinfection can replace chemical methods to disinfect vehicles and other transportation vehicles.
Scientist from Institute of Agricultural Food Research and Technology (Author) Researchers at the University of Catalonia analyzed the heat resistance of coronaviruses to understand the parameters that should be considered in a heat disinfection system that eliminates pathogens.
The results show that if the SARS-CoV-2 viral load in confined spaces and surfaces is exposed to a temperature of 56°C for 52 minutes, or the equivalent of 65°C, they will be inactivated by 99.99%. 7.5 minutes
To conduct this study, the researchers first reviewed existing work on the heat inactivation of different coronaviruses.Then they used the so-called Thermal activation kinetic parametersFor example, the time required to reduce the viral load (TD) by 90% and the thermal resistance constant (z) can quantify the pathogen’s sensitivity to increased treatment temperature.
He explained: “This is how we obtain the thermal lethal equivalent, that is, the combination of time and temperature can ensure a certain degree of elimination of the coronavirus.” Sara BoverThe head of the IRTA food safety research program and the research leader said: “Through this procedure, any pathogen can be heat treated, but so far, the kinetic parameters of the coronavirus have not been described.”
The conditions that affect the viability and survival time of the SARS-CoV-2 virus are not yet known, and scientific information on its thermal persistence is very scarce. Until now, the reference temperature used to inactivate this type of virus is the previous coronavirus, SARS Coronavirus 1, The temperature is inactivated at the temperature of 56 degrees Celsius for 15 minutes.
“Due to the uncertainty of the available information and the differences between different coronaviruses, the time required to inactivate 99.99% of the viral load (equivalent to 4 logarithmic units required for chemical biocides) is safer and more A conservative estimate would be: make the infected space and surface at least 56 degrees Celsius for 52 minutes, Or an equivalent combination,” Bover said.
“If the purpose of disinfection is to reduce SARS-CoV-2 by 99.99999% (ie 7 logarithmic units) in a polluted environment such as a hospital or hospital, it is necessary to apply the equivalent of treatment 56 degrees Celsius for 90 minutes“The scientist pointed out.
Thermal and chemical disinfection
The study concluded that thermal disinfection can be an alternative to chemical methods in spaces and surfaces with coronaviruses, because these places are kept dry and there are no residues. This method of disinfection with heat can be applied to urban and public environments, especially transportation such as buses, trains, taxis, and ambulances.
In fact, the commission for this research comes from the company Techtrans Systems (OPP group), The company has developed a system for thermal disinfection of trucks that transport animals. DrySist. With the new data, you can now make adjustments in the SARS-CoV-2 disinfection in public transportation.
The DrySist system is used to disinfect pig transportation vehicles to resist pathogens, such as Salmonella, Listeria And porcine reproductive and respiratory syndrome virus. At the time, IRTA also facilitated the verification of the system developed by one of its researchers, Cristina Castañé, and OPP Group technicians.