Ultraviolet C (UVC) light can be used to prohibit foodborne pathogens from contaminating fresh fruits, according to a new study.
Scientists at Washington State University said that the findings will be welcomed by organic fruit processors who seek alternatives to chemical sanitizers and must also comply with the U.S. Food Safety Modernization Act to help prevent foodborne illnesses.
The research, published in the International Journal of Food Microbiology, reveals that UVC light is effective against foodborne pathogens on the surface of certain fruits.
“UVC radiation is present in sunlight; however, it is completely absorbed by the ozone layer and Earth’s atmosphere,” explained Washington State University food safety specialist Shyam Sablani. “It has germicidal properties and can be effective against bacteria, mold and viruses.”
UVC light has been used for several years to sanitize food contact surfaces as well as drinking water and contaminated air. Although it cannot penetrate opaque, solid objects, it can be effective in sanitizing surfaces.
Sablani and colleagues investigated the effectiveness of UVC light for inactivating strains of E. coli and listeria on the surface of organic apples, pears, strawberries, red raspberries and cantaloupes.
They found that the light can kill up to 99.9 percent of pathogens on apples and pears. Listeria was more UVC resistant than E. coli, and the technology worked best on fruit with smooth surfaces. That’s because the rough surfaces of fruits like strawberries, raspberries and cantaloupes offer places where pathogens can hide, reducing the effects of the UVC light.
On fruit with rougher skin, UVC light inactivated 90 percent of pathogens present. Research is already underway to increase the effectiveness of UVC light on fruits with rough surfaces, Sablani said.
The technology could be implemented on a fruit packing line by installing UVC lamps enclosed behind protective barriers in a tunnel that exposes fruit to the light as it passes on a conveyor belt.
