Several months ago I canned some ham and pea soup, following this recipe verbatim. All went well and the jars have been sitting in my dark pantry ever since.

This was my very first time (ever) using a pressure canner, and so I have no idea what to expect. I'd like to crack one of the jars open and have some pea soup for dinner this week. At first glance, everything looks ok:

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But then I noticed there is a lighter green (slimy looking) film on the very top of the soup:

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Is this normal, or does this mean its gone bad?

More generally, with pressure canning recipes, what is a good way to tell if the food is safe to consume?

I've heard of the following approach:

  1. Open the lid and confirm you hear the popping sound (the seal breaking), and let it sit in the open for a few minutes, then put the lid back on and put it in the fridge
  2. Wait a day, take it out and inspect
  3. If there is any white foamy substance that sprung up overnight (strong indicator of botulism) or if there are strong off-putting odors, toss it
  4. Otherwise have a bite and wait a day
  5. If by the next day you haven't developed any upset stomach or other GI issues, it is very likely safe to consume the rest

Is this a safe system to follow here? Any other practices or methods anybody can think of? Thanks in advance!

  • Did you sanitize your jars (boiling all the jars inside, boil the lids, rings, tongs, etc) before doing the sealing step? If you just took the jars directly without that step, you probably have bad instructions, I didn't see that part of the process in the link you provided.
    – Ron Beyer
    Commented Feb 17, 2021 at 14:25
  • @RonBeyer Pressure canning sterilizes the jars and lids just as it sterilizes the contents. There's no need for a separate step. You might be thinking of low-temperature canning, like one might do with fruit preserves.
    – Sneftel
    Commented Feb 17, 2021 at 14:32

2 Answers 2


The layer on the top is either separated fat from the ham and bouillon cubes, or a bacterial and/or fungal growth (aka a "pellicle"). If it feels greasy and/or brittle and becomes transparent when heated, it was just fat. If it feels rubbery and maintains its coherence when heated, it was a pellicle. A pellicle is not an indication of a botulinum infection, but it's definitely an indication that you screwed up the canning process and that the contents are inedible.

There is no way for a home cook to determine if a can of food is safe to eat. That would require special expertise and lab work (including, when testing for botulism, injecting mice with the stuff). Instead, what you do is use a trustworthy recipe, make sure you're following the recipe properly (with a canner that reaches the appropriate pressure for the appropriate amount of time), and check that the vacuum seal has not been compromised before eating. That is, rather than seeing whether the food is safe, you ensure that your process guarantees safe food.

The steps you posted are horrible -- neither safe, nor effective, and betraying a fundamental misunderstanding of what botulism even is -- and you should no longer trust whoever wrote them. "Have a bite and wait a day"? Cripes on a cracker.

  • Thanks @Sneftel (+1), do pellicles typically have an odor to them? Commented Feb 16, 2021 at 17:47
  • Possibly but not necessarily, and so might canned pea soup.
    – Sneftel
    Commented Feb 16, 2021 at 17:49
  • FWIW, my money's on congealed fat. It's exactly the right color for it, and something growing on such a thick soup would generally be fuzzy, not compact. The wrinkly surface gives me pause, but could have happened when you were moving the soup.
    – Sneftel
    Commented Feb 16, 2021 at 18:14
  • I ran this same question by a master canner I know through someone else. She said the same thing: likely fat, give it a smell test, try heating it up and breaking it apart, and disregard the "wait and try" method i mentioned earlier. Commented Feb 16, 2021 at 18:30
  • I popped the lid, smells like pea soup and it doesn't look nearly as gross staring in from the top down. Commented Feb 16, 2021 at 18:36

Please note this from the CDC:

Despite its extreme potency, botulinum toxin is easily destroyed. Heating to an internal temperature of 85°C for at least 5 minutes will decontaminate affected food or drink.

Link: https://emergency.cdc.gov/agent/Botulism/clinicians/control.asp

100°C boiling does not destroy botulism spores.

But high temperature destroys the toxin.

So if you follow the CDC recommendation above (make it 10 minutes to be sure), the soup should be safe to eat.

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