The question of whether a household dishwasher can neutralize SARS-CoV-2, the virus that causes COVID-19, is common as people seek to ensure home cleanliness. This concern stems from the possibility of viral transmission through contaminated dishware and utensils. SARS-CoV-2 is an enveloped virus, meaning it is surrounded by a fatty outer layer that makes it highly susceptible to common cleaning agents and heat. The dishwasher uses a dual-action process combining thermal and chemical effects, making it a reliable tool for inactivating the virus on surfaces like plates and silverware.
The Mechanism of Disinfection: Heat and Detergent
The dishwasher relies on the combined power of detergent chemistry and high temperatures to break down and inactivate viruses. Detergents contain surfactants, compounds that lower the surface tension of liquids. These surfactants disrupt the delicate structure of the virus’s outer lipid envelope. By dissolving this fatty outer layer, the detergent causes the virus structure to collapse, rendering it unable to infect cells.
This chemical breakdown is paired with the destructive effect of heat on viral proteins. Viruses are composed of proteins that must maintain a specific shape to function and facilitate infection. High temperatures cause these proteins to rapidly denature, or lose their three-dimensional structure. This process permanently disables the virus, much like how cooking an egg alters its proteins. Exposing the virus to temperatures at or above 65°C (149°F) for several minutes can lead to near-complete inactivation.
Standard vs. Sanitize Settings
While the combination of heat and detergent is effective, specific settings determine the consistency and speed of inactivation. A standard wash cycle typically heats water to temperatures ranging from 54°C to 63°C (130°F to 145°F). This temperature range, combined with detergent, is often sufficient to inactivate a large amount of virus. However, it may not consistently reach the threshold for rapid thermal destruction. The National Sanitation Foundation (NSF) standards for residential dishwashers provide a clear benchmark for guaranteed sanitation.
The “Sanitize” setting is the most reliable option because it is specifically engineered to meet these rigorous standards. To achieve NSF-certified sanitization, the dishwasher must deliver a final rinse that reaches a minimum of 66°C (150°F). Many modern appliances heat water up to 71°C (160°F) or higher during this final stage, holding that temperature for a specified duration. This sustained, higher-temperature exposure provides the necessary conditions for rapid thermal inactivation of SARS-CoV-2. Users should consult their appliance manual to confirm the specific temperature reached and look for an indicator light signaling successful completion.
Beyond the Dishwasher: Handling and Storage Safety
The effectiveness of the dishwasher addresses the risk of surface transmission from the dishware, but risks can still exist during the handling process. If a person in the household is ill, careful management of dirty dishes before the cleaning cycle is prudent. Minimizing direct contact with soiled surfaces and immediately placing items in the appliance helps reduce the chance of spreading viral particles.
Maintaining proper hand hygiene is important before and after loading and unloading the dishwasher. Washing hands with soap and water after handling dirty items ensures any viral residue transferred to the hands is removed. Once the cleaning cycle is complete and the dishes are dry, the risk of transmission from the clean surfaces is considered very low.