Can you store opened tomato paste in the tin can or is it dangerous?

Question

I have a habit of using half a teaspoon of tomato puree for a quick midweek pasta sauce and then leaving the tin to fester in the fridge like a miniature science experiment. My husband insists that keeping opened tomato paste in the tin can is practically a death sentence due to the metal leaching, but I suspect he just enjoys being dramatic.

Is it actually dangerous to store it this way, or am I just being warned off a perfectly good bit of convenince? I would rather not poison the family on a Tuesday night if I can avoid it.

Answer 1

Leaving tomato paste in an opened tin is a bad idea because the high acidity causes the metal to leach into the paste, resulting in a metallic taste and potential spoilage. As a budget cook who relies on smart spending and stretching ingredients across multiple weeknight dinners, ruining a good tube or tin of paste with a metallic tang is a waste of money. To fix this, transfer the leftover paste into a small airtight glass container or freeze it in teaspoon portions on a tray. This keeps your quick pasta sauces tasting fresh and safe all week long.

Answer 2

Hello Claire. While your husband's fear of acute metal poisoning is a bit exaggerated, he is actually right about one thing: you shouldn't leave tomato paste in an opened tin can in the fridge.

Tomato paste is very acidic, which causes it to react with the exposed metal of the can once the protective lining is broken. This won't kill you, but it will give the paste a distinct, unpleasant metallic taste. Furthermore, once opened, the food is exposed to oxygen and bacteria, and the open can cannot be properly sealed, leading to rapid drying out and spoilage.

To safely store your leftover tomato paste, I recommend transferring it to a small airtight glass or plastic container. Alternatively, you can spoon small portions onto a parchment-lined tray, freeze them, and then drop the frozen cubes into a freezer bag for future midweek pastas.

Best regards,
Chef

Answer 3

You can store it in the fridge for a couple of days if you cover it, but it might dry out quickly without a lid.

Answer 4

leaving open cans in the fridge is just asking for trouble, my grandfather always said the tin flavor gets right into the food. just transfer it to a little jar.

Answer 5

Just cover the top of the tin with a piece of aluminum foil and a rubber band, it keeps the air out and stays fresh for weeks in the fridge! 😃👍