Why You Shouldn't Store Open Tins In The Fridge

I saw this open tin of stuffed vine leaves in our office fridge and immediately freaked out. I'd always been told that leaving food in an opened tin risked food poisoning, and I believed that. But then I realised I'd never bothered to question why this rule applied. Time to investigate.

A certain amount of searching later, and the answer is pretty clear. Storing food in the fridge in an opened tin is a bad idea, but it's not because of botulism (at least, not directly). One major issue is that with more acidic foods such as fruit juices and tomatoes, tin and iron can leak into the food, which makes it taste unpleasant and can have health effects. The CSIRO has a good explanation:

Once cans are opened some foods, especially fruit, fruit juices, and tomato products, should be placed in a clean plastic or glass container, covered and stored in the refrigerator. When these foods are stored in the opened metal can, tin and iron will dissolve from the can walls and the food may develop a metallic taste. Food containing high concentrations of tin can cause nausea, vomiting, diarrhoea, abdominal cramps, abdominal bloating, fever or headache. These symptoms pass quickly and there seem to be no long term effects of high tin exposure. However, repackaging food once a can is opened is a good practice to adopt for all foods packaged in metal cans.

The broader problem (and the reason for that last piece of advice) is that once the tin is opened and exposed to the air, food can become dry, absorb other flavours or otherwise turn nasty. That won't make it poisonous, but it can make it unpleasant.

If you have those plastic lids which reseal tins, that problem can be avoided, though I've never used them for anything other than cat food myself. Keep it simple: if you don't use the whole tin, transfer the contents to a resealable container.


Comments

    If you freaked out over a tin can in the fridge, wait till you open your front door and go outside.

    Is covering the tin opening with cling wrap a decent enough solution?

    Wow! That is freaky. I'd be more worried that someone at my work is eating hors d'oeuvres at work.
    What next?
    Some devilled eggs, pigs in a blanket? Maybe some prawns in a shot glass? Asparagus wrapped in bacon with a toothpick in it? :-)

    Why doesn't the tin and iron dissolve from the can walls before the can is opened??

      No exposure to air to trigger a reaction.

        I call shenanigans. There is a lining on the inside of the can (which contains BPA for those interested). This is present after the can is opened; there might be the tiniest but of exposure and corrosion where the can was cut, but that likely won't contact the food as you will have eaten half of the food in the can if you're putting it on the fridge.

        Also I'm quite pleased my Android keyboard knows the word shenanigans. Go SwiftKey!

          i was thinking the same thing.

          Most cans, unless you're buying the cheapest imported crap, are laminated on the inside notice the yellow-ish tint. metal isn't yellow.

          I call bullshit.

          also, upvotes for "shenanigans", that word isn't used enough :)

          Agreed! Cover with plastic wrap and secure with a rubber band/elastic. The only actual problems - drying out and absorbing odors from other foods in the fridge - are solved.

          lol, shenanigans.

    "Food containing high concentrations of tin can cause nausea, vomiting, diarrhoea, abdominal cramps, abdominal bloating, fever or headache."
    Whilst this may well be true, it is highly unlikely that you'll get anywhere near high enough concentrations of tin in the food just by refrigerating it (lots of cans are plastic lined these days anyway).

    http://www.sciencedirect.com/science/article/pii/S0278691503002175

    How does the tin/iron get in there? The sides of cans are usually coated in plastic to stop this happening.

    Actually- this is absolutley true - I grew up next to an (as a kid) an "old man". He was always on his own. I always remembered he lived off canned food. I used to ask him, i remember vividly his shopping bags . cans of beans, sardines, spag - everything possible to eat in tins. Some years later I visited home to find my neibour blind, with a stick. Totally. I remember asking him about it - I can recall the techicalities but it had something to do with his diet of tinned food and the fridge. As he told me himself, it was genuine. It was to me no longer "one if those myths"- It was sobering back then, and even today, I always extract contents the contents into a clean airtight container.

      I would call 'urban myth' on this one. It's most probably the 'contents' of what he was eating rather the fact that it's opened cans in the fridge.

      It is possible to permanently lose vision from lead poisoning. I do not know how long ago this occurred, but in the olden days, apparently there were issues with lead leaching into the food from the cans.

    Most cans have plastic coatings on the inside to prevent this from happening. The problem with that is that the plastic contains BPA so we all get exposed to a chemical that mimics estrogen (https://en.wikipedia.org/wiki/Bisphenol_A).

    So we can choose to be poisoned by tin and iron or by BPA!

    "A certain amount of searching later," - which obviously didn't involve a visit to Wikipedia
    " and the answer is pretty clear." - despite factual errors and further promoting ridiculous myths

    Research fail.

      Yeah - Cause Wikipedia is well know only to contain actual facts and is extremely unlikely to be incorrect.. pffft You Idiot.... lol

        You're half-right, Wikipedia is very likely to be correct.

    Yeah this is totally wrong. Tin, unlike the old days (where they were just tin), are lined with plastic and do not dissolve into food once opened.

    The only area that could oxidise would the tiny tear area on the top of the can.. which doesn't touch the food.

    Additionally these plastic do not leak BPA contrary to popular belief and has been extensively covered by Skeptoid (http://skeptoid.com/episodes/4060).

      So who do you work for Mike, a PR firm hired by one of the big food produers I'm assuming., BPA is being banned in children's products in most countries. Canada has banned it completely in everything. I think I would trust the scientists in a country like Canada who seems to actually care more about it's citizens than sucking up to Big Business than some guy at skeptoid.com who's running his website to make money.

      Your Skeptoid link doesn't even mention BPA, it covers other things but not BPA.

      It is worth noting that because the plastic is a corrosion barrier if there is a tiny break in the barrier corrosion will occur at an accelerated rate compared to if the entire can was exposed to corrosion.(https://en.wikipedia.org/wiki/Corrosion#Applied_coatings)

      So don't buy cans which have been dented!

        1) Plastics tend to be flexible (hence the name 'plastic' which essentially means 'pliable'). Ordinary denting shouldn't damage the coating at all.

        2) As your link suggests, the corrosion can occur at an accelerated rate - but only on the area exposed and only with certain materials. A 'tiny break in the barrier' would cause a correspondingly tiny increase in exposure.

      Did you even read what he said before you named called and tried to make yourself feel superior. For it is you that looks like an idiot for not reading the post correctly.

    I remember doing that when i was a kid, i loved baked bean (in tomato sauce) from a can in my jaffles, if i left it a day it was fine but too long and it did have a metal taste and you could see the oxidation on the can. Granted i don't recall having that problem in the last 15 years but it doesnt mean that cans are not immune.

    But of course the drying out is still an issue worth preventing.

    Do what you like people, open tin in the frig or not... In the end its all about natural selection isn't it?

    This is a load of rubbish. Tins aren't even made of tin any more, they're made of aluminium and coated to prevent contamination. Maybe if you're talking about cans from the 1930's there might be an issue but if that's the case I'd be more worried about the contents than the container.

    First of all modern day "tin" cans have no "tin" in them. They are typically made of aluminum or plate steel. They are also coated with a plastic lining that insulates the food from the metal can. According to the USDA it is perfectly safe to store food in an open can for a couple of days. After that, depending on the type of food, the food begins to degrade as it would in any other type of container in the fridge. The best purchase I have ever made was for a "side cut" can opener that is just the cat's meow. It's a Hamilton Beach 76606Z Smooth Touch Can Opener, Black and Chrome that I bought for $26.93. If you buy this can opener you will never ever buy a standard one again. The lid not only comes off with no-finger-cut smooth edges but then serves as a tight lid for the top of the can.

    http://www.amazon.com/gp/product/B000R4J8PC/ref=oh_details_o05_s01_i01?ie=UTF8&psc=1

    Most cans these days are made of aluminum, at least in America anyway, because it is much cheaper and more accessible than tin is. Steel is probably second most common.

    Actually, only most beverage cans are made of aluminum; soup and tuna cans and such are made of steel. Regarding the whole 'dented or bulged' thing, in extreme cases if food spoils in the can, it can ferment and cause gasses that burst the seams-I've seen it, but its much different than a dented can, which I have no problem with buying at the market for half price. Having said all that, I'm old school and still have little spats with my wife if I find a half can of tuna in the fridge, cause I was raised that way and old thought processes die hard.

      Does this also apply to drinks

    This article doesn't make any sense. "Acid" foods can stay in a can for *YEARS*. But taking the lid
    off causes that exact same high-acid food to quickly damage the can... and destroy the food.

    > If you have those plastic lids which reseal tins, that problem can be avoided,

    Why in world would a plastic lid (again) make the high-acid food... not harm the can?

    The best purchase I've ever made was probably Netflix. Then again without a computer I couldn't watch Netflix so that was a pretty good deal too. Without a computer I couldn't read this blog post for that matter, and I suppose the lamp to see the keyboard was a damn good purchase too. Then there's the car I bought to drive down to Future shop and buy the computer. And the garage on my house to park the car in...

    But hell if them can openers are that good I might just consider selling it all. Wonder how many I could buy if I sold my house? ...

    Thanks for the recommendation.

    The United States Department of Agriculture says it's safe to refrigerate canned foods manufactured in the United States directly in the can.

    That said, the USDA still doesn't advise it. The reason is that canned foods will better retain their flavor and appearance if you transfer them to glass or plastic storage containers after opening.

    gold is gold not yellow :P

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