Current Topics:Wine Kills Several Types of Foodborne Pathogens

Wine Kills Several Types of Foodborne Pathogens

Folk advice that wine with raw oysters wards off food poisoning may have merit. Mark Daeschel, a microbiologist and food scientist at Oregon State University in Corvallis, who plans to develop a marketable disinfectant based on the antibacterial properties of wine. He notes that wine already is widely praised for its heart-healthy antioxidants.

Former graduate student Jessica Just and Daeschel tested wines against bacterial pathogens such as Escherichia coli O157 or Salmonella enterica serovar Typhimurium in a model stomach system, which consists of a bag containing otherwise sterile synthetic gastric fluids and food materials. Within 60 minutes after adding either a chardonnay (white) or pinot noir (red) wine to the mix, E. coli was inactivated. Under similar conditions, Salmonella was inactivated within 10 to 30 minutes. Other experiments indicate that such wines also kill Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae. A report of this study is scheduled to appear in the Journal of Food Science later this year.

Several components in wine that are not present in grape juice appear essential for the antibacterial activity. For example, the same bacteria survived for up to 16 days in unfermented juice from the same chardonnay or pinot noir grapes. To further identify the active ingredients, the researchers distilled the wines into nonvolatile fractions containing acids and volatile fractions containing alcohol. The acid fractions kill bacteria faster and more efficiently than do the alcohol-containing fractions, and the chardonnay acid fraction kills bacteria better than does the pinot noir acid fraction.

These results suggest that the antimicrobial activity of wine depends more on its acids (mainly malic and tartaric) than alcohol content. In general, ``white wines are more acidic than red wines,'' says Daeschel. The findings also suggest that people who drink wine with meals may protect themselves from food poisoning.

Daeschel is seeking funds to harness wine's antimicrobial capabilities. He and undergraduate student Joy Waite formulated a wine-based spray disinfectant and tested it on pieces of Formica coated with the nonpathogenic test organism Pediococcus pentosaceus. Their experimental disinfectant kills these bacteria as well as does a commercial cleaner containing hydrogen peroxide. A wine-based disinfectant could offer consumers a biodegradable, natural alternative that is environmentally safe--so long as it is used as directed, not consumed. ``That appeals to people concerned about their exposure to chemical residues,'' says Daeschel.

He plans to produce the wine-based disinfectant from waste wine. Typically, wineries discard 1-3% of wine that they produce when it does not meet quality or flavor specifications. The environmental consequences of dumping waste wine are largely unknown, but probably tax the biological oxidation demands of the local environment. Although some waste wine is fermented to vinegar, the wine industry would welcome additional outlets for discarded batches.

Carol Potera
Carol Potera is a freelance writer in Great Falls, Mont.

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