Botulism In Home Canned Foods | Should I Be Worried?

How to destroy botulism in home canned foods.

No, you don’t need to be concerned about botulism if you followed recipes and instructions from reliable sources. Botulism from home canned foods are rare these days – given the well established safe processes.

However I do want to mention it, because it’s just good to know… especially if you’re into home canning.

From the National Center for Home Food Preservation:

Pressure canning is the only recommended method for canning meat, poultry, seafood, and vege­tables.

The bacterium Clostridium botulinum is destroyed in low-acid foods when they are processed at the correct time and pressure in pressure canners.

Using boiling water canners for these foods poses a real risk of botulism poisoning.”

What are low acid foods?

Low-acid foods have a pH level greater than 4.6, which means they are not acidic enough to prevent the growth of botulinum bacteria. Examples are:

  • Asparagus
  • Green beans
  • Beets
  • Corn
  • Potatoes
  • Some tomatoes *
  • Figs
  • All meats
  • Fish and seafood

*Tomatoes require added acid – lemon juice or citric acid – for safe home canning.

Why do I need to use a pressure canner for these foods?

Because it can reach temperatures above boiling, which is necessary to kill botulism spores.

Botulism Spores & Toxins

There are two things to bear in mind while talking about botulism. There are the botulism spores, and then there’s the botulism toxin. The spores create the toxins.

If the spores are present and not destroyed during the home canning process, they will later produce the toxin. It is the toxin which is the dangerous thing. Potentially causing paralysis and death. Therefore it is essential to destroy the spores so there’s nothing to produce the toxin.

But don’t let me scare you away from canning! It’s a rare thing these days for botulism toxin poisoning from home canning. Well established recipes and processes assure safe canning.

What Kills Botulism Spores?

(from UC Agriculture and Natural Resources)

Killing spores is a time and temperature relationship and it is also heavily influenced by the properties of the food. This is why we do not have one process that is applicable to all low acid foods.

The processes for low acid foods can range from 20 to 100 min at 240 to 250 F. Altitude affects the maximum temperature achieved and can thus impact processing times. Higher altitudes require longer processing times.

[ Water Bath canning only reaches 212 F, while pressure canners reach 240 to 250 F at proper pressures]

What Kills Botulism Toxin?

We’re not talking about the spores (which require high temperature during pressure canning to destroy). Rather, the resulting toxin…

Despite its extreme potency, botulinum toxin is easily destroyed. Heating to an internal temperature of 85°C (185° F) for at least 5 minutes will decontaminate affected food. (source)

If Clostridium botulinum bacteria survive and grow inside a sealed jar of food, they can pro­duce a poisonous toxin. Even a taste of food containing this toxin can be fatal.

Boiling food 10 minutes at altitudes below 1,000 feet altitude should destroy this poison when it is present. For altitudes at and above 1,000 feet, add 1 additional minute per 1,000 feet additional elevation.

Boiling means that you are able to see the liquid in the food actively forming large foamy bubbles that break all over the surface.

~ nchfp.uga.edu

Though it is a good safety precaution, do not rely on boiling your home canned food prior to consumption to destroy the toxin. Instead, use a pressure canner and do it right.

THE TAKEAWAY

Follow home canning recipes and processing techniques from established trusted sources.

Use a pressure canner when it calls for one. Even though your grandmother (or you!) may have successfully water-bath canned low-acid foods (by adding acids, long processing, etc.), better safe than sorry. Use a pressure canner.

Boil your low-acid canned foods for 10 minutes before consuming. Rather than microwaving, we always heat our home canned foods to at least 212 F (boiling temperature) for at least 10 minutes (e.g. beans, corn, tomato sauce, meats etc..). Either on the stove top, or in the oven, or a crock-pot, etc. Just in case…

[ Read: All American Pressure Canner (That Will Last Forever) ]

The Latest Ball Book of Canning and Preserving
(view on amzn)

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20 Comments

  1. We were anchored in Bahia Magdalena on our way to the Sea of Cortez. A small group of sailboats had informally assembled on the way down.

    We left with one of boat lagging. That next day we were concerned because we had not heard anything. It turned out that the guy on the boat had opened a jar of home canned cod. That night he became so sick he could not reach his VHF radio that was 5 ft away. Botulism can paralyze you. Untreated it has a 60 percent mortality rate. He recovered but he couldn’t get up for 2 days.

  2. What is your opinion on canning bacon? I’ve read articles of those who have safely canned it, but was not sure it’s a safe practice.

    1. Depends on how it’s done. The main point is temperature and pressure enough to kill the possible bacteria. So yes, it could be done safely provided the heat can reach all the meat. However, bacon is a high fat product which introduces the possibility of other problems.

    2. I actually did some pressure canned bacon last week. I tried one of the jars a couple of days later and made some BLT’s that were pretty good. I’m always pressure canning various meats, but really wanted to try Bacon. I think with the pressure canning and the time spent at high heat, it should eliminate any trace of the Botulism spores/toxin.

      DT

  3. I have a question. If you live at high altitude (7600 ft here)you pressure can at 15 pounds of pressure and as long as you use 15 instead of 10 lbs you can process it for the same length of time. And then there is another book that if you process it at 15 lb instead of 10 lbs, you also have to add time. Which is correct?

    1. I may be wrong, but I believe this guideline is in regards to water bath canning. Higher altitudes = longer times. I can see no reason why you would also have to add time with the higher pressure.

    2. The following site has very useful information regarding home canning:

      https://nchfp.uga.edu/publications/publications_usda.html

      To address your question, it likely depends on the specific recipe. One recipe may take into account that 15 psi will properly compensate internal temperature due to your altitude. While another recipe may or may not. If in doubt, err on the side of safety. More time won’t hurt.

      Also, trust more recent pressure canner recipe books (be sure they are brand name for trust). Example: Ball (I’ve linked it in the article above).

  4. Nice one Ken. Wife canes figs and cucumbers every year. This year we didn’t get hardly any cucumbers? the Figs are slow. The pinto beans were terrible as well. We pressure caned some bacon a few years ago and I’m not sure I wont to try eating it. Maybe we’ll try to heat it in the oven for 10 minutes at 212 F. But only if it looks ok when we open the can. What do you think?

    1. Regarding your canned bacon concern, if it were me, Perhaps heating in oven at 350 or thereabout will provide thorough assurance prior to consumption.

  5. My family has been Canning and Preserving foods for more generations than I can count, yes canning all sorts of meats and the allusive Bacon, and about anything else that comes in a can from a store/Garden/wild.

    To the best of my knowledge we have never had a concern.
    I cannot say the same for mass production foods, take a hard look at the “Recall” list….

    With that said I’ll reiterated Ken’s Article, use the guidelines, add the time OR pressures required for high altitude, AND most importantly “When in doubt, Toss it out”, do NOT just feed it to the Dog’s, botchulisum poison will kill animals also, including the Chickens and Rabbits.

    1. NRP & Blue,
      I have never known anyone who canned having issues with botulism. I do remember the news when that one company’s canned mushrooms had botulism back in the late 60s, and people died. They must have screwed up that operation in a major way.
      And yet today, people by the millions can’t wait to inject botulism poison into their faces in the name of vanity. Don’t tell me the world has not gone mad.

        1. Kulafarmer:
          A man of understatements
          Bonkers?????
          How about all out STUPID??? As per Blue

  6. So what this article says is I could still look good (ok, a little less fugly) during a SHTF or WROL event. I could under cook some meat now. And if my face starts getting a little saggy during an event, I could just inject some meat juice in the saggy area. Homemade Botox treatments.

    Just kidding

  7. A subject that’s come up elsewhere is the risk of botulism when using oxygen absorbers with somewhat under-dehydrated foods that have been vacuum packaged. Comments? Veggies are supposed to be dried to 5% moisture, fruits, 10%.

    1. Dogpatch

      I always wondered about that, too, seeing as moisture – oxygen = perfect botulism environment. I could never find anything to address that issue to my satisfaction, so I just dry the heck out of everything, let it cool and fill to the brim a clean, dry canning jar w/lid. I have never used oxygen absorbers, and have never vac-sealed my jars either. So far, I’ve never had anything go bad, and have sometimes used things from 2-3 years ago (chopped peppers and leeks).

      This is not to say what I do is at all correct or safe or etc…just that it’s been working for me to do it that way. I do watch for mold and wrong odor, but haven’t had a problem. Did I mention I dry the heck out of everything?

    2. Dogpatch,
      When I do my elk jerky, I dry it to hardness after it has been marinated for a day or two in the refrigerator (like to use Yosida’s teriyaki marinade). then vacuum package it without oxygen absorbers. I have never had a complaint about it being ‘too hard’, even though it is so dry it will snap if you bend it. low moisture for sure. If some like it softer, I tell them to cut open the package, and put a slice of apple in there for a day or two , and that usually softens the jerky up some.

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