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19 Comments

  1. Good article.

    Would remind readers that all food is organic based (not inorganic, but for trace minerals used by enzymes for a few biochemical reactions) and generally will not degrade unless exposed to a degradation (heat) environment or conversion through some enzymatic process (like digestion) or oxidation (exposure to oxygen) or in rare instances to light.

    Canning kills microorganism through a process where the DNA (and enzymes) is broken down by heat – the DNA and enzymes are an organic molecular structure but very susceptible to heat, radiation and enzymatic actions. Canning breaks these chemical bonds and prevents the microorganism from replicating and spoiling the food. Food preservation by irradiation is still used today and very effective but costly and safe. The organic material (carbohydrates and proteins) are far less susceptible to breakdown by heating but may degrade the quality of the food’s appearance and texture or tast) but the nutritional value will generally persist with only modest reductions over time; while fats are susceptible to oxidation, heat and breakdown from light and difficult to store.

    Up until the advent of canning – be it the tin cans or glass jars approach – most food storage was based on curing, smoking, dehydration or cooling – otherwise the food was consumed immediately. The advent of canning has been one of the events in history that has change the world dramatically – all places on the planet that have seen the advent of canned food have seen a dramatic increase in their standard of living (and our waistlines) but now threatens those that are so reliant on such food.

    As we all know, a disruption in our ever so fragile supply chain business models with a focus on just-in-time inventory managements is what makes our life so fragile.

    Having clean water, and a balanced long term supply of canned and dehydrated food is the only insurance policy to mange the risk of a food supply disruption (until the farm to market roads start to work again for those of us that know the history of our early roads system).

    Likely persuaded me to stock up on some more canned food, especially if you shop carefully (and store thoughtfully) and may also be time to look at the cost benefits of buying a $250 pressure canning equipment and the jars. Maybe a good bartering plan for those of us without a green thumb or big 2+ acre garden – I’ll can the food you grow if I get some for me.

    This article brought back memories from 35+ years ago in those food science classes in college – should have paid more attention and saved those books – since not much has really change in this science.

    As to Clostridium bacteria – in simple terms, what’s unique about this bacteria is that it is able to go into a phase of hibernation when environmental conditions would otherwise kill most bacteria – it creates a spore like structure that protects the DNA and crictical enzymes from heat and dehydration – the spore will allow the bacteria to come back to life and begin to replicate but if the bacteria is in a low oxygen environment it creates a by-product from the anaerobic metabolism that is a neurotoxin that is very heat tolerant and will not breakdown (similar to other food poisoning by stahloccocus bacteria) and therein is the problem. Spore formation can happen quickly in response to a quick change in the environment and still may be found in canned food – it’s only if the canned food then is kept in the right conditions after opening the food that may still be a problem from the neurotoxin or by infection in your gut (and the danger to young babies that don’t have a mature well developed gut flora to counter such an infection). The best indication of a bad canning situation is a bloated can – something is degrading and producing gas – never a good sign but not necessarily from clostridium bacteria. By the way, you can find this bacteria everyday in the soil nearly everywhere – it’s only if you but this bacteria in the right conditions that it creates the deadly poison that is heat tolerant and highly toxic. The other bacteria in this family also causes tetanus – step on a nail in your garden, and there’s a chance to get tetanus (lock jaw) from the neurotoxin from this bacteria that is a cousin of the one that causes botulism.

    Thanks for sharing and reminding us of the facts and opportunities – has prompted me to rethink the mix of types of food storage in the future., but not sure if I can convince my better half to start canning with me.

  3. What are your thoughts on oven “dry” canning of food with less than 10% moisture? I did this method and later found out it is not a safe procedure. Also, I noticed some moisture on a few of my jars on the sides and inside lid. I immediately released the seal now I’m concerned the food was comprised. Was that low-oxygen environment with moisture enough to produce the botulism bacteria? Been searching for answers as I it would be a lot of food I would have to discard. Thanks.

    1. I would toss the food. The food needs to be dried to very low moisture before being sealed in a jar. I use a vacuum sealer to seal dried food in jars. It works extremely well. The jar will do an excellent job of keeping moisture out, once sealed, just as it keeps moisture in with regular canning.

  4. I never tire of reading articles detailing basic information like this. I know that the Survivalblog readership is ever increasing. Repeating this kind of material provides new preppers with a window on reality not readily available in the usual day-to-day flow of information. It is nice to hear a little truth speak in the midst of all the spin.

  5. What are your thoughts on oven “dry” canning of food with less than 10% moisture? I did this method and later found out it is not a safe procedure. Also, I noticed some moisture on a few of my jars on the sides and inside lid. I immediately released the seal now I’m concerned the food was comprised. Was that low-oxygen environment with moisture enough to produce the botulism bacteria? Been searching for answers as it would be a lot of food I would have to discard. Thanks.

  7. Part of my food preps are store bought canned food. I keep them in the basement pantry using a rotation system first in first out. Its not uncommon to be using 2014 use by dated cans, we’ve never had a problem with any of them.

    Once we’ve used about 25% of any particular stack, say cream of chicken soup, it goes on my shopping list and I start looking around for the best sale price. Its a simple process and usually I’ll save 40% buying on sale over just buying singles off the shelf.

    The interesting trend is following the prices year over year, where for instance using the cream of chicken soup as an example the price has gone up 4x over the last 16 years, and if you don’t buy on sale, its closer to 7x.

  8. The only commercially canned food I have had storage issues with are tomato products and some fruit, peaches for example.They seem to eat through or expand the can. For this reason, I don’t stockpile those items anymore. I avoid foods canned in China as well. I just don’t trust the non-toxicity of their process.

  10. Just used a jar of home canned beef which I put up 11 years ago. It was overlooked in my rotation. I used it in a beef vegetable soup and it was as tasty as it was months after canning.I did note, however, that there were signs that enamel on the inner side of the lid was starting to show signs of corrosion. When this happens, the lid usually does not last for many more years.
    Of course it was pressure canned – we have been pressure canning for more than 50 years and I can count on the fingers of one hand the number of failures we have sustained Have to ad mit we do use the water bath for our pickles – they really turn to mush under pressure and we like the crunch we get with the lower temperatures. They are all used up in the following year so there is no problem.

  11. I’m starting to see rust on some of the cans in storage. I noted the lid on a Campbell’s tomato soup can with a best buy year of 2016. It had light rust and when I opened it found that the rust had penetrated to the side of the can under the seam. Our daily use can opener is one that cuts the metal on the side of the can just under the lid. I probably wouldn’t have noted the rust penetration if it was a top opened can. I guess my concerns here is the quality of the steel. I know a lot of steel is coming out of China and much of it is poor quality. I can’t help but wonder abut this effecting my storage.

  12. Canned foods from 40 years ago MAY be different than canned foods today. It’s the cans and how they are finished inside. I see what looks like laquer in some cans. Anyone care to comment?

    1. I have canned food in metal cans in my stash, but not a lot. There are many reasons.
      1. Metal rusts and corrodes, especially in this wet climate. It doesn’t matter what measures we take, it will rot down.
      2. As mentioned in the article, some foods that are high in acid help to rot the metal, no matter the inner lining.
      3. I want to be able to control the ingredients that are in those foods. I cannot eat most preservatives.
      4. I trust myself and my processes way more than I trust some tired, bored (even angry) factory worker who does this everyday for years on end.
      5. A glass jar with a metal lid is more likely to survive better than an entirely metal can. It is also easier to tell if it is unsealed.
      6. I can grow it myself with organic means, or nearly organic means.

      Hence, the reason I personally can most of our food instead of buying it.

  13. Expiration dates do not contribute to safety for the consumer. The dates encourage the waste of perfectly good food by encouraging people to throwing out usable food to increase sales.

    Starvation does not contribute to safety or security. It does contribute to avoidable suffering and death.

  14. Grow what you eat, eat what you grow – for those who do not grow, substitute the word “buy.” Point being that it is important in times of extreme stress to retain what normalcy you can. By ensuring that your diet is not a gross departure from what your normal, everyday diet consists of, you are raising the odds against a weakened immune system and gastrointestinal problems. Moreover, it ensures that you rotate your stock and become more proficient year over year in growing and thriving on what you produce and preserve.

  15. I switched to canning with plastic lids and no longer worry too much about corrosion. Tattler lids are a bit harder to get right in the process. But with practice, the fails go away. The nice thing is the lids are reusable, so all I have to replace are the rubber seals. The rings come off after the canning process prior to storage, and are kept dry in a drawer for later use.

  16. Mart
    May 28, 2017 at 2:08 pm

    The botulinum toxin is denatured and thus deactivated at temperatures greater than 80 °C (176 °F).
    (Wikipedia)

    Mart, are you referring to when the food is canned or when the can is opened and you cook/warm the contents (176 F)? It seems if heat would kill the bacteria, then wouldn’t one just heat to a safe temp and serve?

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