I've read a bunch of threads on botulism risks in various foods, but had a specific question about a recipe I sometimes use.

This is for a pizza sauce. The recipe calls for:

1 can (28 oz) of crushed tomatoes 2 cloves of garlic, minced 1.5 teaspoons of salt 2 tablespoons of olive oil

One just mixes everything together. No cooking. The recipe says you can leave it in the fridge covered for up to a week. But I was wondering: if I put this in a plastic bowl, filled halfway, cover it tightly with Saran-wrap and then leave it in the fridge for a week, can it grow botulism because of the mixture of garlic and a small amount of olive oil? Is a half filled bowl considered anaerobic because the garlic would be completely submersed in the tomato / oil mixture? I've read that tomatoes may not have a low-enough pH to inhibit botulism growth. Even though it would get cooked at a high temperature in the oven later on, I still wouldn't want to take any chances, so am curious if there's any risk with this.

I appreciate any advice you may have! Many thanks.

  • For what it's worth, I noticed that the canned tomatoes I use have "citric acid" added to them.
    – pizza fan
    May 19, 2018 at 18:37
  • I suspect but cannot verify the USDA would probably be inclined to say 3-4 days rather than a week but that may be splitting hairs a bit. Botulism is real, but rare and the risks increase rapidly with time. Consider though glass rather than plastic to insure porous plastic does not increase risk as a thought.
    – dlb
    Jan 17, 2019 at 17:46

3 Answers 3


First, a little context...botulism is extremely rare...only 145 cases in the US in 2015, and of those, only 15% were food borne according to the CDC. You do need to be aware and careful, but not fearful. There are lots of easier ways to get sick and die.

Secondly, the risk is higher in low acid vegetables (pH of 4.6 or higher). Garlic is an example of a low acid vegetable, but canned tomatoes range from 3.5 to 4.7 on the pH scale (the lower the number, the higher the acidity). Adding lemon, of course increases the acidity, but also impacts the flavor.

Third, colstridium botulinum spores are very heat tolerant. You need at least 241 degrees F to kill them. So, boiling, or a quick saute, would eliminate any toxins present, but would not eliminate spores. Cooking your tomato sauce makes it immediately safer (you have eliminated potential toxins), but not from the standpoint of eliminating the spores, because you will never get it to that temperature on your stove or in your oven. That is why pressure canning (where you can achieve higher temperatures) or pickling (higher acidity preparations) or high sugar preserving are used. These techniques all reduce the risk.

Even with all of the risks accounted for, a week in the fridge, makes sense...probably not much more. I would make that sauce and feel comfortable with it for about a week...even better if it was being cooked, such as on your pizza. I would probably discard after a week or so.

  • Botulism cannot grow below 4C. Botulism is only a risk for food that is claimed to be shelf stable. However, it can spoil from many other sources as well, just as anything may spoil in a fridge. May 23, 2019 at 6:10

I really don’t think you need to worry about botulism, unless it was already present in your canned tomatoes. If you are worried, though, add 1 or 2 tsp of bottled lemon juice (bottled, not fresh, because bottled lemon juice has a uniform pH level). That’s what you do when canning tomatoes or pasta sauce at home.

Alternately, even though the recipe is no-cook, you could always give it a good boil before you store it!

  • 1
    Regarding the "good boil before you store it": pizza fan specifies that the sauce will be cooked at high temperature later on on the pizza. His question is not about storing the uncooked sauce long-term. He merely mentions that it can be kept "in the fridge for a week". This doesn't seem to be any different from any other uncooked food which may contain botulism spores/organisms which do exist in our natural environment. Boiling will kill the living organisms, and adults can cope with b. spores. Poisoning happens when you let the spores go rampant in a friendly environment, & eat w/o cooking
    – Lorel C.
    May 19, 2018 at 16:48

The problem with this recipe and its directions is the raw garlic and letting the bacteria incubate for a week.

Because of the low acid and low temperature, there is a very slight risk, but it is still a risk

Saute the garlic in the oil and you'll eliminate that risk. Or, add the garlic just prior to serving


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