Noroviruses are a group of viruses that are the most common cause of gastroenteritis (stomach bugs). They are very contagious and can spread easily from person to person. People exposed to the virus usually develop symptoms of illness within 24 to 48 hours, but symptoms can occur as early as 12 hours after exposure.
Common-sense based disinfection guidelines to control norovirus contamination have been developed, but now, for the first time, a Dutch team has come up with science-based guidelines.
In the study the researchers first determined how low the concentration of virions needed to go for transmission to become unlikely. They then tested different methods of cleaning hard surfaces, by using water, soap, or chlorine bleach solutions to determine the best method, or combination of methods for achieving a sufficiently low concentration to prevent virus transmission from hard surfaces, such as your kitchen counters.
The researchers prescribe a two-step process: wipe with a wet cloth, and then disinfect with chlorine. Their prescription is directed at hospitals, schools, restaurants, and other food-handling establishments. In most cases, a 250 ppm solution of chlorine is sufficient, but for high levels of contamination, they recommend 1,000 ppm. To achieve 1,000 ppm, one Suma Tab D4 tablet must be dissolved in 1.5 liters of water (about a quart and a half).
Norovirus is no more resistant to cleaning and disinfection than other pathogens. The virus’ efficiency in causing outbreaks “is more likely due to their extremely low infectious dose,” resulting in the requirement of a very low level of residual contamination in order to prevent further transmission. Fortunately, reducing the level of residual contamination to that low level is not that difficult and can be achieved without extreme measures.
FoodWorld 