Grape-seed extract, a byproduct of wine and grape juice production, is a popular dietary supplement taken by many Europeans for high cholesterol and hypertension. Research published in Applied and Environmental Microbiology suggests grape-seed extract also has natural disinfectant properties that may help to prevent outbreaks of severe gastroenteritis from highly infectious noroviruses, the cause of 60% of food-related illnesses in the U.S.
U.S. and Belgian scientists tested grape-seed extract on cultured cells, vegetable rinse water, and food-preparation surfaces infected with a surrogate mouse strain of norovirus.
Grape-seed extract contained 13% catechin and 19% epicatechin, nontoxic plant-based compounds known as flavonoids, which have been shown to have many antioxidant and antimicrobial effects on human health.
Grape-seed extract treatment neutralized the virus's infectious properties to undetectable levels in cell cultures, though a higher dose was needed when a small amount of dried milk was added to the culture, indicating proteins may interfere with grape-seed extract, researchers said.
The extract also reduced the virus's potency in norovirus-contaminated water used to wash lettuce, but had no significant effect on contaminated stainless-steel surfaces. After treatment, norovirus particles clumped together and appeared deformed; the virus's outer protein shell was also damaged.
The findings may be important to the food industry as fresh produce is often implicated in norovirus outbreaks, researchers said.
Caveat: As human noroviruses aren't easily cultured, the experiments used a surrogate strain of the virus that shares the biological features of human norovirus.
A version of this article appeared October 23, 2012, on page D2 in the U.S. edition of The Wall Street Journal, with the headline: Possible Fighters of Food-Borne Ills: Grape Seeds.