9

Recently I've seen uncooked, prewrapped-in-foil potatoes at the store, meant for baking. But I've always read that keeping potatoes wrapped tightly in foil at room temperature is one of the ways that botulism can occur. Is this a safe product? Is it only after cooking that botulism can grow?

6

One of the nicer things about botulism (there are not many) is that heat does neutralize the toxin. So unless you are licking the raw potatoes, not likely to be a problem.

The odds of the foil-wrapping being actually airtight are also about zero, so it's unlikely that you'd actually get botulism, as that requires an anaerobic environment.

Now, why you'd buy foil-wrapped potatoes in the first place is beyond me, but I'm not seeing a safety issue here.

  • I thought like you, and at least could hardly believe the foil wrapping able to be airtight, in addition to other (what I thought were) improbabilities, but see this report .... ncbi.nlm.nih.gov/pubmed/9652437 ...excerpted: "In April 1994, the largest outbreak of botulism in the United States since 1978 occurred in El Paso, Texas. ... Toxin formation resulted from holding aluminum foil-wrapped baked potatoes at room temperature, apparently for several days,.... be informed of the potential hazards caused by holding foil-wrapped potatoes at ambient temperatures after cooking." – Lorel C. Mar 3 '18 at 19:11
  • 2
    An interesting data point, but if you cook them and then eat them hot like normal people, I'm still not seeing a problem. Toxin would be destroyed by the heat (spores won't) and if you don't then store them at room temperature, unlikely to be an issue. However, I prefer to just bake them (no foil) anyway. – Ecnerwal Mar 4 '18 at 0:26
4

From what I understand about this, it's not so much about the raw potatoes being foil wrapped as it is about the baking and storing afterward.

From EnCognitive.com:

Though rare, most foodborne botulism in the U.S. is from improper home canning. But according to a report from the Centers for Disease Control and Prevention, potatoes baked in aluminum foil and left at room temperature can also cause botulism. Here's why.

As a common soil-dwelling organism, C. botulinum can easily contaminate potatoes or any other crop that comes in direct contact with soil. Thorough cooking usually kills the organism's spores, the source of the deadly toxin. But a foil-wrapped potato holds in moisture, sometimes preventing its surface from reaching a high enough temperature to kill spores. Paradoxically, the heat kills off competing bacteria, making it easier for C. botulinum to grow. Moreover, at room temperature, foil-wrapped potatoes provide the oxygen-free environment needed for toxins to form.

Advice? If you bake potatoes in foil, do not leave them out for any significant period of time, even unwrapped. As with any food, eat it soon after cooking or refrigerate it promptly. The Journal of Infectious Diseases, July 1998.

Many others sources also recommend that, after baking, potatoes should be immediately removed from the foil and not allowed to remain in the danger zone. Translate that to unwrap and serve or refrigerate right away.

One downside I can think of to the pre-wrapped potatoes would be if they are not kept at proper storage temperatures, moisture/condensate could accumulate inside the foil. And you can't see inside the foil to determine the overall appearance and quality of the potato.

  • This follows basic food safety advice, where any combination of wet, light, food, temperature/danger zone, and time can result in pathogen growth (increasing any of those factors increases risk). Keeping the potato wet and in the danger zone, in addition to any other factor, will increase risk. – Bruce Alderson Mar 7 '18 at 4:56

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.