Vacuum-packed cheese, stored in refrigerator for awhile (2-3 weeks), then placed in freezer. Cheddar and Provolone.

Any risks, especially in regards to botulism...opinions sought. Never heard about botulism being a risk in vacuum-packed food until recently, and now am concerned and want to know about the cheese I stored in freezer if I can consider it well.

Thank you for opinions/information.

  • 1
    Cheese is an especially poor candidate for botulinum toxin accumulation due to the lactic acid content. Lactic acid has been shown to severely limit the growth of Clostridium botulinum and the formation of spores of the same species. I forget the exact reference, but you should be able to find it on jstor easily. Commented Dec 8, 2014 at 13:44
  • @jbarker2160 Good to know regarding my current frozen cheese. Do you think it would be better, in the future, for me to simply unwrap such cheese from its vacuum pack and re-wrap in freezer bag instead of placing in freezer as was bought? I understand what both repliers to my post have stated, and you told me any such growth would be , if at all, severely limited. That is reassuring. But, for future reference, after using this cheese, future purchases, would you think it better I unwrap their vacuum packing and store in freezer bags having air? Cheese would be used within the year likely.
    – Bluebird
    Commented Dec 8, 2014 at 17:59
  • Air in the freezer is your enemy. I would try to avoid any unnecessary exposure to the air prior to freezing, but I don't think it will make a huge difference except maybe with freezer burn issues. Commented Dec 8, 2014 at 18:52

4 Answers 4


No, there's no risk. Cheese has too much salt and acidity to harbor botulism even at room temperature; there's practically no chance of it growing in the refrigerator even with low-acid food, and literally zero chance of it growing in the freezer on any food.

I don't think data is publicly available on individual botulism cases in the U.S. or worldwide, but aside from honey-related infant botulism, the vast majority of cases are reputed to be from improper home canning of low-acid foods (garlic, peppers, etc.), and that number is still very small. I don't think I've ever heard of a single case related to cheese.

Seriously, stop worrying about botulism unless you are either (a) caring for an infant or (b) canning your own foods at home.

  • Canada has public data and charts available showing the number of botulism cases per year: dsol-smed.phac-aspc.gc.ca/dsol-smed/ndis/charts.php?c=yl There is no information on the source of those cases, though. Commented Dec 11, 2014 at 13:46
  • That was my point - there isn't a readily available source of information on individual cases, we can only extrapolate from the vague aggregates.
    – Aaronut
    Commented Dec 13, 2014 at 5:43
  • I have some vacuum packed organic mozzarella (tastes well-aged) that didn't have an expiry date. I avoided eating it for a few weeks and now it seems to have small, flat bubbles under the plastic. It's not really swollen but seems a bit strange. It is quite a salty cheese normally but wondering if something is going on in its airless environment (not opened yet). (Taking into consideration your answers to the above question).
    – padma
    Commented Dec 13, 2014 at 6:13
  • 1
    @padma: No, it's not botulism. Forget botulism, especially in the fridge. Cheese is a cultured product, meaning it already started out as one massive bacterial colony. Mozzarella cheese in particular is also a curd cheese. Could be curd separation, could be moisture condensation, could be just about anything other than botulism. I've left unopened cheese in the fridge for up to a year with no ill effect. Just because botulism is an anaerobe doesn't mean it will grow in every airtight environment; it just means that it can, given the right conditions.
    – Aaronut
    Commented Dec 13, 2014 at 21:07

One other consideration regarding vacuum-sealed products is how well the pouch acts as a barrier to oxygen transport into the package. The typical nylon/polyester vac pouch is relatively permeable to oxygen, and that oxygen would tend to inhibit the growth of C. botulinum inside the package. A mylar pouch is much less permeable, and probably would not be a good choice for cheese.

In addition, you have acidity, salinity, and temperature working for you. A cheese, vac-sealed in a typical 3-mil nylon/polyester pouch, stored in the refrigerator would have a very, very tiny risk of botulism contamination.


Vacuum packing ready to eat foods held under refrigerated conditions does require a double barrier to the sporification of C. bot. This is achieved through refrigeration and another barrier, i.e. pH, water activity, or salt content. While cheese is not a good candidate for C.bot it is still possible under the correct conditions. You should check with the manufacturer for the scientific specifications of the cheese you plan to vacuum pack. Items that have a pH above 4.6 would fall under 21 CFR 113 for thermal processed foods for wholesale. While retail sale and vacuum packing activities would fall under State law and may require a scheduled process from a recognized food processing authority.

  • these cheeses were purchased already vacuum-packed
    – Esther
    Commented Nov 22, 2022 at 19:44

Ok, a vacuume packed sealed package is not an open package in the refrigerator constantly being exposed to the air. I love to burst your bubble, their is more about Swiss cheese and botulism than arguments againsts.

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