Garlic Oil [split from Quebec]
There's also a food supplement called garlic oil that you take in pill form and would likely be at Jean Coutu.
Anyway, rather than buying it from a store, a good recipe is to combine about 6 cloves of garlic and about 2 cups of extra virgin olive oil (or just regular vegetable oil, as the garlic adds a lot of flavor) and puree it with an immersion blender. Strain out the solids and put the oil in a squeeze bottle. Voila!
It's the same method that restaurants use to make "infused" oils. I always keep a bottle of scallion oil on hand to drizzle over eggs with soy sauce.
I usually keep my infused oils in the fridge for about 1-2 months before I finish them off. I just used my month old scallion oil today and it is totally fine.
The things that lead to spoilage are air and moisture. But there is neither of those in the bottle as the particles are all suspended in the oil.
It is really important to use a squeeze bottle, as it allows for easy dispensation, and also, you aren't sticking dirty utensils into a jar (which may lead to spoilage). They are cheap at Dollarama or Mona's or my personal favorite, Aubut.
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Yes, unlike most food spoilage organisms, the botulism bacteria are actually anaerobic meaning they grow precisely in the absence of oxygen. And all those particles of garlic or scallion are moist enough for the bacteria to grow on, if the spores are present and other conditions are right. Storing it in the fridge is better than at room temperature, but it's still a risk.
Exactly how much of a risk one takes by storing raw garlic oil for a long time would be hard to quantify, people obviously do it, and don't get sick much less die, but you can say that about a lot of "risky behaviors" - it doesn't mean they aren't in fact potentially dangerous. :) And the potential danger here isn't just garden-variety food poisoning. Botulism is rare, and these days even more rarely kills, but when it does occur, it involves serious neurological damage and takes a very long time to recover from.
FWIW, pretty much every body of food police I've come across frowns on storing infused oils for very long at all - no more than a week in the fridge, I think.
In her cookbook The Slow Mediterranean Kitchen, Paula Wolfert says that a herbed and garliced oil used to poach salmon at fairly low temperatures (145-155ºF) will keep for up to one week in the fridge. In private, she confessed that cookbook authors in the litigious US are obliged to err on the side of caution and that the oil could probably be safely kept for twice that long. If the oil were stored in a freezer, I imagine its shelf life would be considerably longer.
Raw garlic in unheated oil is even more susceptible to spoilage. I vaguely recall an online discussion about peeled cloves stored in oil in which one week in the fridge was given as the upper limit. As SnackHappy implies, flavourless, odourless botulism is the great danger.