Tulare County

Storing fresh herbs, chilies or garlic in oil at room temperature can be dangerous. Vegetables are low-acid foods and can support the growth and toxin produced by the bacteria Clostridium botulinum (which cause botulism) when given the right conditions. These conditions include the improper preparation and storage of fresh herb and garlic-in-oil mixtures. Moisture, room temperature, lack of oxygen, and low-acid conditions all favor the growth of Clostridium botulinum.

Linda J. Harris, Food Safety and Applied Microbiology Specialist in the Department of Food Science and Technology at UC Davis has recently reviewed and revised our recommendations. As with all research, research on food preservation is ongoing and recommendations may change.

Following are our current recommendations:

Flavored Oils: Oils containing fresh, low-acid ingredients such as fresh herbs or fresh chilies must be refrigerated and no longer than three weeks. Be sure to date. Do not store at room temperature.

Pesto Sauce: This is a puree of fresh basil, fresh garlic, pine nuts, olive oil, and Parmesan cheese. The mixture can be safely refrigerated for a maximum of three weeks or frozen until quality suffers. Be sure to date. Do not store at room temperature.

Dried Tomatoes Packed in Oil: As long as no fresh herbs or fresh cloves of garlic (or other fresh vegetables) are packed in with the oil and tomatoes, they can be safely stored at room temperature until the oil turns rancid.

Storing Garlic in Oil: Peeled garlic cloves may be submerged in oil and stored in the freezer for several months. They may be stored in the refrigerator for up to three weeks maximum. Be sure to date. Do not store garlic in oil at room temperature. The same hazard exists for roasted garlic stored in oil. As an alternative, properly prepared dried garlic cloves may be safely added to flavored oils.

Sun-Dried Tomatoes: Place tomatoes in a bowl and sprinkle quickly with distilled white vinegar. Toss the pieces rapidly with your hands, just to moisten lightly. Quickly empty the bowl onto a double layer of paper towels and pat dry.

Pack tomatoes lightly into clean pint or half-pint jars. Add dried rosemary, sweet basil or oregano, if desired. Cover with olive oil to ½ inch from jar rim.

Store in refrigerator or process half-pints for 15 minutes, 20 minutes for pints at 170-190° F. Let cool and store in a cool, dark, dry place.

Hot Oriental Stir Fry Oil Charles Fernandez, Master Food Preserver

Place ingredients in a pan and heat over medium heat until you begin to see a few tiny bubbles starting to drift up from the bottom of the pan. Reduce the heat to low for two hours. Don't let the oil come anywhere near a simmer. Remove pan from burner and cool for 30 minutes. Pour oil through a fine-meshed sieve that has been lined with multiple layers of cheesecloth, into a clean jar or bottle. Cap. May be stored at room temperature or in the refrigerator.

Instructions for Gift Giving: If you are planning to give homemade flavored oil, pesto sauce or dried tomatoes packed in oil as a gift, be sure to label the gift to include the following handling instructions: