Dented tins

[Alfee]

A while ago I heard that dented canned food is not the best to consume.

1) Firstly is this true?
2) If so, what is the reason behind this?

[mycats]

I asume its because the vaccum that keeps the food fresh might have been broken

[nickmo]

The European Food Safety Council says - '...don't eat from dented tins...'

Info at a link here if you are bored...scroll down for 'storage' details...lots of other off putting info there too....

As above, seals may be damaged. And the damage may be so slight it is not noticed when buying that cheap tin, but you'll know it when you eat the contents if bacteria has got in.....

[Alfee]

Thanks nickmo, but unfortunately your link has a fault.

[BillStickers]

Also there is the possibility of metal splinters coming off the inside of the tin and into the food.

[nickmo]

Hi A - try this link: http://www.eufic.org

Then at the foot of the page click:

Articles

Then.. The Basics
Then.. Food Safety

Scroll down to section 1.4 - the 'consumers role in safety practices'

Worth a trip through the rest of the site if you have an interst in food practice, hygiene, food safety, weight issues, additives, consumer input to European food...etc etc

Hope this ok

[nuttymum]

its because the actual tin has a coating to stop contamination, and when dented it breaks the coating and contamination begins before even being opened. Same with never leave the food in the tin once opened, always put in tupperware when storing in fridge. Boring I kno

[nickmo]

And to expand on that - tin cans are made of steel - with a coating of tin to prevent oxidation of the steel that would lead to food spoilage.

Some cans then have further linings (you see this as a white coat in the can itself called a lacquer) to prevent acids in the foods attacking the tin linings causing deterioration of flavour and nutritional value. Different food types have different lacquers that protect the tin linings according to the potential breakdown of the tin due to 'acidic corrosion / reactions.

Damage the linings and the food will be affected by micro-organism i.e. bacterial infection; tin transfer into the food - i.e. the ph/acidity, tin crystal size in the manufacture etc - which is a toxin if safe levels are exceeded - can happen; nitrates and sulphides in the foods will increase the degree of deterioration....and so on.

Isn't stuff about food interesting?........and as an aside, its now found that oxygen depletion in food packaging can increase the effects of listeria by 100 times...! It all leads to buying fresh and seasonal, not factory based, mass produced stuff...

[ACB312]

I've read all the above and tend to agree but what's the score with tinned tomatoes, especially Napolina, it's almost impossible to find an undented tin. I've never had any problem with the dented ones I've used.
Cheers, Andy

[nickmo]

Andy -

The commercial canning process heat treats the produce to sterilise it, then the food is put into cans and again heat sealed leaving no airspace which would allow the growth of bacteria/microorganisms. Dents in the can subsequent to packing that do not affect the tin lining (as commented above) will therefore not afffect the contents...but it is up to the consumer to chance it.


Some foods like tomatoes that have a pH value close to 4.6 need to have acid added to them in order to satisfactorily use them in canning, like adding lemon juice or citric acid (sometimes firming agents like calcium carbonate is also added to retain 'body' in the produce as well) which could affect the lining due to transfer of the tin into the food due to the action of the acids...so a double potentail for contamination.

That said, there are a lot of cans of tomatoes sold and though I have opened one in the past that sceamed at me and requested I put the lid back on (very weird...) the chances/rosks of being affected by food poisoning from canned food are deemed 'acceptable'...