Botulism in oil packed foods We hear all about botulism in garlic oil and the needed preventive measures. Is this only true of garlic or is it just more common. For example I make a oil packed fish (oil, salt onions, jalapeño, fish) I’ve been making this for years with no problems. Have I just been lucky or is my keeping it in the fridge what’s saved me and if so how long is safe?
Any low-oxygen low-acid environment with sufficient moisture can lead to the growth of botulism (see page 6 of this USDA guide to canning). Botulism spores are present throughout your kitchen, not just on garlic. To can low-acid foods safely, you need to use a pressure canner for a sufficiently long processing time.
Refrigeration slows down the growth of botulism. The CDC recommends storing garlic or herb infused oils in the fridge for at most 4 days. You should be at least this cautious with your oil-packed fish.