This is a new jar of peanut butter, never opened. I’ve just noticed that it’s “dented.” What I mean by this is, the jar is behaving as though a little air had been sucked out of it. It is slightly collapsed. I’m not sure how better to explain it.
My question is, is it a bad idea to eat this peanut butter? Am I going to get botulism or something?
-Kris
As long as it’s still airtight, I wouldn’t be concerned.
You are aware of the recent Peter Pan brand recall due to salmonella? FDA update. Outside of that you’ve likely little to worry about.
Since manufacturers use vacuum packing the dent is evidence that the jar is still under vacuum and therefore not contaminated.
While that link asserts that “vacuum packing” is used, I am doubtful of this claim. I have opened many a jar of peanut butter in my time, and I do not ever remember hearing that tell-tale sound as air rushes in to the empty space. Sealed, yes, they do that. Vacuum sealed? Skeptical.
I opened a dented can of pumpkin filling that put me off of pumpkin for the rest of my days. Due to that, I avoid all dented containers.
Are you posting posthumously? 
Pretty damn close. It happened 30 years ago and I can still imagine the horrible smell. :eek:
That’s totally different. There’s a coating on the inside of food cans that keep the food from touching the can (and the can from touching the food). There’s a chance that when the can dented, it’s coating cracked and the metal came in contact with the food and rusted. That could be the cause of the problem. Also, if it was a hard enough hit, it may have actually broken the can itself, but the crack can be hidden by the label so you might not notice it.
Well, it hasn’t hurt me yet and I eat a lot of the stuff. Take my anecdotal “proof” for what it’s worth. 
Okay thanks everyone.
For some reason, I thought the problem with “dented” food containers was that the bacteria that produce the various scary poisons and whatnot do so in part by metabolizing gasses that exist in the can, and in doing so, reduce the volume of the material that exists in the can, and, since the can is airtight, this causes the can to dent.
I thought a similar phenomenon might occur when it comes to peanut butter jars.
But it looks like that’s not what was happening in cans in the first place after all. So my worry was unfounded.
-FrL-
The number of manufacturers who use vacuum is probably as varied as the amount of vacuum.
peanut butter is genmerally pretty warm, even hot, when it is “squirted” into the jars. Generally, the temp is regulated so that the atmospheric pressure drop due to cooling doesn’t cause the plastic jar to “collapse”, but it sounds as if you got a jar that was a little too warm when it was filled, hence greater “collapse”, creating the “dented” appearance’
I would be more concerned about a bulging/pressureized container, as that indicates that some biological process (spoilage) had occured.
Regards
FML
It’s the swollen can you need to look out for; it can mean the nasty buggies are producing toxic gases. Dented cans aren’t quite as scary but still aren’t great. However a sucked-in plastic peanut butter jar shouldn’t be a problem; there’s no metals to worry about.