Recipe: Storing In, and Flavoring Oil Safely

Here is some info I had on storing in oil. Botulism actually thrives on the environment such as food in oil. It grows in the absence of air. Putting food in the oil does just that, it feeds the botulism. This info should tell you about how long one may safely store things in oil and which items work to store that way. It seems this says 3 weeks, but we always tell folks no more than 2 weeks. Cooking the garlic will still not change the length of storage time.

Storing In, and Flavoring Oil Safely

Oil flavored with herbs can be safetly and economically made at home if sound instructions are followed exactly. The following safe guidelines established by USDA can help you evaluate flavored oil recipes you encounter.

Low acid foods such as herbs, mushrooms, peppers and garlic can support the growth of bacteria such as Clostridium botulinum which grows without air (oil makes anaerobic conditions) and produces toxin at room temperature. When consumed, such an oil would cause severe illness. Commercial flavored oils are acidified so can be stored at room temperature, unfortunately a safe recommendation for acidifying home made flavored oils has not been researched. Therefore, householders must alter the conditions of their oil so bacteria cannot grow. Lowering the temperature so bacteria cannot grow, or using dried herbs which lack the moisture to support bacteria growth are ways householders can keep their flavored oils safe.

When vegetables or herbs are immediately removed after flavoring the oil, the bacteria will not have a "food source" for growth. This strained flavored oil can be stored safely at room temperature, but will become rancid after several months. Rancidity is detected by off odors and off flavors. Rancidity is primarily a quality change, but there are safety concerns when rancid foods are routinely consumed over a long period of time. The rancidity problem makes it difficult to make flavored oils in the summer when herbs are abundant and economical to give as December holiday gifts. Many gift givers simply purchase herbs in winter and give freshly made oils.

When vegetables or herbs are dried, there is not enough moisture to support pathogen growth, so dried vegetables or dried herbs in oil can be stored safely at room temperature. However, the flavor of oils made with dried herbs and garlic is different from oils made with fresh, so making a small batch to see if the flavor is acceptable to you is advised.

Some people want their flavored oils to be the pretty bottles with lush green herbs and red peppers setting on the kitchen counter similar to the flavored vinegar bottles. This CANNOT be done safely. Flavored vinegars contain so much acid, that bacteria do not grow in them so flavored vinegars do not have to be refrigerated.

Fresh Herbs and Garlic in Oil
When raw or cooked vegetables or herbs are stored in oil, these mixtures must be refrigerated to slow bacterial growth. After 3 weeks refrigeration, the increased number of bacteria will become a food safety hazard; so that is the maximum storage time.

Flavored oils can be safely stored in the freezer, but some herbs become limp, black objects when frozen. Freezing will delay the oil from becoming rancid for 4 to 6 months. Some people have had success freezing strained flavored oils. You may wish to try a small batch and see if the texture is acceptable to you.