Bulletin #4385, Safe Homemade Flavored and Infused Oils

Food Safety Facts

Developed by Jason Bolton, Assistant Extension Professor and Food Safety Specialist, University of Maine Cooperative Extension. Reviewed by Alfred A. Bushway, Professor Emeritus Food Science and Human Nutrition, University of Maine, and updated by Beth Calder, Extension Professor and Food Science Specialist, Director of the Food Testing Services, University of Maine Cooperative Extension.

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Flavored or infused oils can add excitement and new flavors to your meals. They can be used in salads, marinades, sauces, and dips. However, infused oils are considered low acid foods and may pose food safety risks if not properly prepared.

The primary concern with infused oils is the extremely dangerous and sometimes deadly microorganism, Clostridium botulinum (C. bot), which can cause botulism. Fresh vegetables, herbs, and/or fruits used to flavor or infuse oils most likely contain C. bot spores. Fresh produce also has a high moisture content, which may allow bacteria such as C. bot to grow. C. bot thrives in an oxygen-free environment and why flavored and infused oils must be made and stored correctly to prevent botulism.

Note: The following instructions are NOT meant for retail products, ONLY home use.

Preparing Flavored and Infused Oils at Home

Start by washing, sanitizing, and thoroughly drying the container and lid of your choice. A glass container with a metal cap (and plastisol or rubber lined ring) is recommended. Glass bottles can be placed in boiling water for 10-minutes to sanitize them. They can then be removed and allowed to air-dry upside down. Instead of boiling in water, caps and bottles can be sanitized by dipping into a dilute bleach solution (with lukewarm water) using a germicidal bleach product and follow the directions to produce a food contact sanitizing solution and use the proper contact time. It should say “germicidal bleach” on the label and have an EPA registration number, as well.

1. Best Home Method: Flavored or Infused Oils from Dried Spices

Using dried garlic and/or herbs is the safest way to make infused oils. Dried herbs and garlic lack moisture so that bacteria can’t grow in the oil.

Select a quality olive or other vegetable oil. Add your dried flavor additives to a clean and sanitized container. Heat the oil to 180°F in a pot. Pour the hot oil over the dried additives, add a 1/2-inch headspace, cap your container, and then invert the container (or lay it on its side) for at least 5-minutes. Allow the containers to cool at room temperature.

Storage

Store oil containing commercially dried garlic, vegetables, and/or herbs in a cool, dark place. This helps prevent the fats in the oil from going rancid. Rancid vegetable oil may have a slightly off smell, but may not look any different. However, rancid oil has been linked to cancer and early aging. Do not store infused homemade oils more than three months. After three months, throw away any unused oil. Placing a label with the production date is a great way to track how long the infused oil has been stored.

2. Flavored and Infused Oils from fresh, acidified ingredients

Infused or flavored oils with fresh garlic, vegetables, or herbs should be tested and approved by a food processing authority to prevent C. bot growth. For more information, see University of Maine Cooperative Extension bulletin #3101, Recipe to Market: How to Start a Specialty Food Business in Maine or contact your local processing authority, Association of Food and Drug Officials.

Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.

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