I've always been told that if you see air bubbles in canned food, you should treat it like toxic waste. Today I opened a can of tomatoes and saw a few air bubbles form along the edges of the can. Is this what I was warned about? Or are they talking about food that looks like it's fizzing or oozing out of the can?

Here's a picture. There were ~2-3x that many bubbles when I first opened the can.

enter image description here


  • I didn't notice whether there was a sound of air escaping when I opened the can. It was noisy in the room.
  • The can hadn't been extensively shaken or agitated before opening.
  • If it's hard to tell from the picture, that's enough of an answer for me. I just want to know whether this even remotely resembles what the "air bubbles" warning is talking about, or if it's totally unrelated.

2 Answers 2



It's a realative thing. What you're trying to determine is: where these gas bubbles generated out of something inside liquid portion of the can?

The reason that can be hard to determine is that many cans have a little air trapped in them. If the can has been agitated at all (doesn't need to be extensively), then you can get what look like bubbles coming from the tomatoes themselves, and it can be pretty hard to tell.

I generally look at it from a quantity/location standpoint: are the bubbles throughout the liquid, or are there only a few along one edge? In the end though, with tomatoes, I'd do what SAJ said. While they're probably OK, the penalty if they're not is pretty darned severe, and canned tomatoes are cheap.

  • Definitely, they aren't an expensive ingredient. I've never seen air bubbles in canned tomatoes, and if I ever saw them I'd chuck them.
    – GdD
    May 3, 2014 at 19:25
  • Thanks, this is what I suspected. I did try transferring the tomatoes to another container to see if there was more air trapped inside, and the results were... inconclusive. And yes, I'm not eating them.
    – octern
    May 3, 2014 at 23:04

I don't think many of us have actually seen bad canned tomatoes. It is exceedingly rare.

The risk versus reward ratio to save a bit of tomato which is not very expensive just isn't worth it.


  • That's surely the right choice in the absence of any better knowledge, but I'd still like to know if this is even the kind of thing the warning is talking about.
    – octern
    May 3, 2014 at 18:24

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