Homemade flavored oils make dangerous gifts (Released: 12/1/95)
by Renu Sehgal, Office of University Communications.
STORRS, Conn. -- Homemade flavored oils may seem like wonderful holiday presents, but instead of good cheer they could give your friends and family botulism, according to University of Connecticut food safety experts.
Flavored oils and garlic in oil products began appearing on the market a few years ago. But some commercial garlic oil mixtures were found to be toxic as a result of botulism poisoning, said Diane Wright Hirsch, a food and nutrition educator with UConn's Cooperative Extension System. Commercial products must now contain a preservative to prevent bacterial growth.
The culprit in these cases is Clostridium botulinum, a bacteria present in soil. The bacteria causes foodborne disease by producing a deadly toxin when allowed to survive in an oxygen free, low acid environment, she said. The toxin is destroyed by boiling liquid for 10 minutes and thick food for 20 minutes, but flavored oils are used often on salads and other uncooked food.
Vegetable oils, which are thick and squeeze out all air from around food, can protect the toxin from heat destruction to some degree, Hirsch said. Garlic and onion products are particularly risky for the bacteria because they are grown underground.
Home concoctions such as garlic in oil, herbs in oil, tomatoes in oil or eggplant in oil could all be risky, she said. If they are made, they must be refrigerated and used within 24 hours. Any vegetables used should be chopped into small pieces, she said.
A safer gourmet treat is flavored vinegar. Vinegar is so high in acid that bacteria do not grow, Hirsch said.
As for cruets of flavored oils in restaurants, Hirsch recommends asking questions before sampling. Find out how and when the oil was prepared and stored. The oils should not have been left at room temperature for more than two to four hours.
For more information on food safety or home food preservation, contact Hirsch at (203) 789-7865 or Kenneth Hall, a Cooperative Extension Service food safety specialist and a professor in the Department of Nutritional Sciences, at (860) 486-1763.