I saw an open tin of stuffed vine leaves in our office fridge one day and immediately freaked out. I’d always been told that you should never leave food in an opened tin as it risks food poisoning — and I believed that. But then I realised I’d never bothered to question why this rule applied. Time to investigate.
After a bit of digging, the answer is pretty clear. Storing food in the fridge in an opened tin is a bad idea. But while you might expect that to be because of botulism (a rare but potentially fatal form of food poisoning), that’s not the main concern here. One major issue with storing open tins in the fridge is that with more acidic foods such as fruit juices and tomatoes, tin and iron can leak into the food, which makes it taste awful and can impact your health.
The CSIRO explains:
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.
That last tip from the CSIRO points to a bigger issues at play — once a tin is opened and exposed to air, food can become dry, absorb other flavours or otherwise turn nasty. That won’t make it poisonous, but it can make it unpleasant to eat. And no body wants that.
If you have those plastic lids which reseal tins, you can potentially avoid that problem, but I’ve never used them for anything other than cat food, personally.
Keep it simple: if you don’t use the whole tin, transfer the contents to a resealable container. And as an added bonus tip: if you go with glass containers, they don’t absorb odours or colour from food like plastic containers do.
This story has been updated since its original publication.