This website by Colorado State University has a lot of really good information on the preparation, storage and recipes for flavored oils and vinegars.

Last year I did a program on making flavored oils and vinegars and did a lot of research on the subject since I know you have to be very careful when making it, storing it and using it. And I'm sure that you already know about the possibility of problems with making flavored oils and vinegars, but I just want to remind readers that herbal oils and vinegars can be very dangerous if not prepared and stored correctly. Please read the website listed above for more information.

NOTE about using garlic in vinegars and oils:

 OIL: Garlic, vegetable or herb in oil mixtures may support the growth of Clostridium botulinum bacteria. As a result the Food and Drug Administration has issued a warning that leftovers should be frozen, refrigerated no longer than ten days, or discarded. For safety reasons, they should be made fresh.

 VINEGAR: Because vinegar is high in acid, it does not support the growth of Clostridium botulinum bacteria. However, some vinegars, wine and rice, may support the growth of Escherichia coli bacteria because they contain a protein that provides an excellent medium for bacterial growth if not stored properly. It is suggested that if making garlic vinegar, make only small batches and keep it refrigerated for no longer than three weeks.

What about store bought garlic olive oil? There's one I've bought in the past and used, (sorry, I don't remember the name of it) but since I started hearing the warnings about garlic olive oil, I quit buying it - that and it's easy enough to combine some garlic and olive oil for immediate use anyway. But, I'm still curious about the safety of the store bought stuff.

Sally

I don't use store bought flavored oils nor vinegars if they have bits of "stuff" in them. And I really have a problem when I see those decorative bottles packed full of things like garlic and herbs and olives. I sure hope no one ever puts oil from one of them on my salad!
Linda C

Good questions asked here. I used to buy the store-bought flavored oils and vinegars, but no longer do so. And I caught my son just refilling his empty flavored oil bottle by just adding more oil all the time and letting the bottle sit on the stove. I came unglued with him and told him that he was risking botulism poisoning for the whole family. And although the FDA is supposed to make sure that these items are strictly supervised, I just would rather make my own so I know that they are safe.

When giving a program, I always insist that all bottles, stoppers, instruments, etc. be sterilized and completely dried, along with the herbs being totally dry. Otherwise, you risk lots of problems. Also, I date and refrigerate my oils. And if giving flavored oils and/or vinegars as a gift, be sure to state the flavor, expiration date (you can estimate this), and tell them to be sure to refrigerate.

It is my understanding the the FDA regulates oils and vinegars by requiring a lower pH (acidic) to control bacteria contamination. For more information, you might want to check out the following websites:

http://www.cfsan.fda.gov/list.html

http://postharvest.ucdavis.edu/datastorefiles/234-209.pdf

http://www.ces.ncsu.edu/depts/foodsci/ext/pubs/herbalfoods.html

Commercially prepared oils are acidified under controlled conditions. AFAIK, there's no research about a comparable level of acidification for the home cook.

Ellie Topp came up with a method of driving off water from the oil by gently heating, which does reduce the risk. That doesn't mean other considerations can be ignored, just that it improves the odds of a healthful product. Her method was approved by the Canadian government.

Using dried amendments as opposed to fresh also reduces risk. A dried pepper in oil is not problematic compared to a fresh one.

Below is a link to a page which provides access to PDF documents outlining Ellie Topp's method. In this instance canola oil was used, but I've used olive oil and olive oil blends with no problem.

Carol

Here is a link that might be useful: Preparing Flavored Oils Safely