We all do it – store cloves of cut garlic in the fridge. If it is short term, as in overnight, or the garlic is used in a vinaigrette, it’s probably safe because the acid in the vinegar or lemon juice offers some protection. A high ratio of dissolved sugar helps, too. Vinaigrettes tend to have acid, sugar or both.
But what of the trend of “canning” or sealing cloves of garlic to season olive oil?
Don’t do it.
The pH of garlic ranges from 5.3 to 6.3. It’s considered a low-acid vegetable. Holding it in olive oil will promote the growth of toxic bacteria, including that which causes botulism.
If untreated, death can result in a few days of consuming food with Clostridium botulinum, the bacteria that flourishes where moisture, room temperature, lack of oxygen and low acid concentrations combine.
Garlic or dill dropped in a jar of pickles is OK because pickles are preserved in an acid environment, but garlic, like green beans and many other non-acidic vegetables, needs heat or freezing temperatures to preserve it once it is submerged in a liquid medium.
Flavoring a counter-top decanter of olive oil with a fresh slice of garlic amounts to a potentially lethal combination that favors the growth of this deadly bacterium, despite what you may have heard.
Instead, store garlic separately in a cool dry environment and use it as needed.
