Researchers at the University of Missouri-Columbia conducted studies in which they examined the effects of reseveratrol — the compound responsible for wine's red colouring — as well as ethanol and pH levels on common food pathogens such as E. coli, Salmonella typhimurium, Listeria monocytogenes and H. pylori.
They discovered that in addition to ethanol, reseveratrol and pH may inhibit the pathogens.
In the study, Cabernet, Zinfandel and Merlot wines were found to be particularly effective in defending against food-borne pathogens and had high anti-microbial properties.
Yet the wines didn't have a negative effect on probiotic bacteria, which fight harmful bacteria in the intestines.
"This study showed that the four probiotics tested weren't inhibited by red wines; the pathogens were," said Azlin Mustapha, associate professor of food science at the University of Missouri-Columbia.
Numerous white wines also were tested, but yielded no positive results, the researchers said.
"It's not just ethanol in the red wine that is inhibitory toward food-borne pathogens, but other factors which include the pH of the wine — because wines are a little acidic, and possibly the phytochemicals may have an effect," said Mustapha, noting that grape juice produces similar results.
"We hypothesize that these phytochemicals, reseveratrol being the main one, also play a role not just as antioxidants but also may have some inhibitions against food-borne pathogens."