Why did my food explode?
April 9, 2007 3:46 PM   Subscribe

Why did my hummus explode?

I bought hummus last weekend from Trader Joes. Garlic. No preservatives, but the sell-by date was April 11, two days after today. I brought it home and put it in the fridge. It swelled. A lot. So I stuck a knife into the thin plastic covering (the this has not been tampered with stuff) and it exploded (in my sink). Why? I mean, I assume some serious fermenting was going on, but what? And why in this case? I've had hummus a lot longer and never had this happen.
posted by dame to Food & Drink (25 answers total) 2 users marked this as a favorite
Best answer: Fermenting beans (or chickpeas) produce a lot of gas. Maybe the product had been time/temperature abused?

posted by fiercecupcake at 3:58 PM on April 9, 2007

Best answer: The chickpeas could have been undercooked, not enough lemon juice may have been added, or it may have become contaminated at any point. Sounds like it fermented earlier than it might normally ferment, so one of the above is likely. It may or may not be safe to eat at this point -- I wouldn't chance it.
posted by solid-one-love at 4:00 PM on April 9, 2007

The hummus wasn't prepared properly at the factory, or stored properly, so despite the sell-by date, it was going bad and bacterial action was creating carbon dioxide, methane and various other gases. Garden-variety biology.
posted by frogan at 4:02 PM on April 9, 2007

It happens from time to time, anything can ferment if it gets the wrong kind of bacteria in it. Some equipment at wherever it was manufactured might not have been cleaned properly, or the container might not have been fully sterilized. I had something similar happen once, I bought a box of yogurt cartons and 2 of them had swelled to nearly the point of bursting.
posted by TungstenChef at 4:03 PM on April 9, 2007

It may or may not be safe to eat at this point

It is so NOT safe to eat at this point. Hell, you really should be washing your hands and kitchen surfaces after this explosive event.
posted by frogan at 4:03 PM on April 9, 2007

Response by poster: It totally smells fine. I have yet to decide about eating it.
posted by dame at 4:04 PM on April 9, 2007

Best answer: Eat it. Hell, have me over and we can both eat it.
posted by ThePinkSuperhero at 4:06 PM on April 9, 2007 [1 favorite]

goes well with flammable carrots.
posted by phaedon at 4:11 PM on April 9, 2007

That gas is coming from something productive in your hummus. Whatever that something is, it's not what the manufacturer/packager intended to have being all productive. Won't necessarily kill you, but it's not the food you were ostensibly buying.

And part of this is starting to sound kinda familiar. Heh.
posted by cortex at 4:13 PM on April 9, 2007

Best answer: This is bad. Take it back to the store, if you still have it. If it was fermenting (or whatnot) then it definitely was not packed cleanly. There must have been some kind of bacteria in there that was producing gas. Bacteria, in this case, i would assume, is bad.

I don't think this is a hummus thing, I think this is a packaging/disinfecting/purifying problem, with either the food or the packaging itself.

Seriously, you should tell the Trader Joes people. They'll probably give you free hummus! (Plus, they should know.)
posted by Kololo at 4:15 PM on April 9, 2007

Response by poster: Well, I might take it back, because then you can skip the line, and if you have ever been to the Manhattan Trader Joes, you'd know what that is worth.

Cortex, I do not think it will kill me and will not be pouring bleach all over my sink. I do not think it is even processed on machines that process meat. I am just curious as to whether it is a time + heat thing or a hummus thing.
posted by dame at 4:20 PM on April 9, 2007

I do not think it is even processed on machines that process meat.

I'm not sure what this has to do with the safety of the product. Hummus can contain nasty bugs without having been processed on a machine that touches meat. Most of the pre-packaged store brand hummus in the UK was recalled a couple of months ago because of salmonella contamination. Most the major supermarkets got their hummus from the same factory—who knew?
posted by grouse at 4:45 PM on April 9, 2007

Response by poster: Just to be clear, the question is not "should I eat it?" Rather it is, "What makes hummus likely to explode?"
posted by dame at 5:11 PM on April 9, 2007

The most common bacteria seem to be listeria and salmonella.
posted by MsMolly at 5:53 PM on April 9, 2007

It should be pointed out that eating this might be the worst mistake you ever make. Witness what can happen to garlic in an anaerobic environment:

Garlic-in-oil associated botulism: episode leads to product modification

I repeat: Do Not Eat This.
posted by griffey at 6:29 PM on April 9, 2007

Doesn't botulism cause expansion? I've heard it's odorless, too.

See the "prevention" section of Wikipedia's botulism toxin entry. You _do_ want to clean your kitchen thoroughly.

Even if you never do anything remotely like "home canning", someone who uses your kitchen later might. I have no idea how long the bacteria can sit dormant - you could look it up.
posted by amtho at 6:42 PM on April 9, 2007

Best answer: I repeat: Do Not Eat This.

And she repeats: the question is not "should I eat it?" Rather it is, "What makes hummus likely to explode?"

posted by languagehat at 7:33 PM on April 9, 2007

what caused the hummus to explode was basic thermodynamics: pressure built up inside the package and you released it. pop a balloon, similar effect (if less messy).

what made the pressure rise inside the package was gases given off from fermentation or bacterial production.

although this was not part of your question, i would concur with others who have said not to eat it. botulism doesn't make your food smell or look rotten, but it can kill you. it's why there's that blister on the lids of jars that say "do not use if button is raised."
posted by thinkingwoman at 7:43 PM on April 9, 2007

Dude, I would eat the tuna sandwich and the can of crab meat and most of this funky bread/cheese with the bad parts removed but you could not pay me enough to eat that hummus. Seriously bad idea. The explosion was a self destruct mechanism. Honor it.
posted by hindmost at 8:35 PM on April 9, 2007 [2 favorites]

Goodness, hindmost, your post made me realise that for some reason, I click on all the 'can i eat it' questions. And I have no idea why.

Especially since the answer is always "don't eat it, dumbass."

Also, it's humourous that the 'can i eat it' rubric is so entrenched that every question about foul food now gets answered as if 'can i eat it' was the question. We don't know how to deviate from the model anymore.
posted by Kololo at 9:25 PM on April 9, 2007

Dame, you can be certain a microbe was involved, likely a bacterium, less likely yeast. The reason the hummus "exploded" was because, in the course of eating your hummus, this microbe was producing waste gas, usually carbon dioxide. That pressurized your airtight-sealed canister of hummus; when you pierced the plastic, the pressurized contents sought to escape, much the same way that paint comes out of a spray paint can.

There's no easy way to find out what kind of bug it was. A medical lab would use a microscope, some slides and some stains to identify it.

Botulism (Clostridium botulinum) is one of the gas-formers that can build up an extremely high head of pressure, deforming or sometimes exploding tin cans. When micrograms of botulinum toxin are injected into facial muscles, the result is a flaccid paralysis of those muscles, reducing their ability to deform the overlying skin (and cause wrinkles.) However, when milligrams or grams of botulinum toxin are ingested, the result is a progressive paralysis leading to respiratory failure and death by suffocation.

If you eat the hummus, get sick, and go to the hospital, you can spend a couple of weeks on mechanical ventilation, with a tube down your throat doing all your breathing for you. When your strength returns - slowly, over weeks to months - you will be weaned from the ventilator with a tracheostomy. Eventually you will regain voluntary movement and you can then focus on healing your bedsores. Speech and swallowing, via a Passey-Muir speaking valve plugging your tracheostomy, will be laborious to reacquire, requiring many sessions with a speech therapist.

About that time is when I would like to see a followup to this post, citing the laboratory studies that provided a definitive ID of the microbe. That will satisfy our collective curiosity.

Thanks in advance!
posted by ikkyu2 at 9:45 PM on April 9, 2007 [3 favorites]

When I hear or read "My (packaged) food exploded" my brain immediately goes Botulism! and thinks that staying far far away is a good idea.

If it smells fine, I would be even more suspicious. A yeasty/fermenty reaction tends to make things smell funny.
posted by that girl at 6:34 AM on April 10, 2007

And she repeats: the question is not "should I eat it?" Rather it is, "What makes hummus likely to explode?"


Given that botulism is odourless, tasteless, grows in non-acidic, anaerobic conditions, and given that it is deadly in very small amounts, and given that dame has specifically stated that she does not think it will kill her, a certain amount of "for the love of dog, PLEASE DON'T EAT IT" is perfectly reasonable, and even advisable.
posted by carmen at 9:11 AM on April 10, 2007 [1 favorite]

For the record, I had the exact same problem with hummus from trader joe's a week or two ago, but I didn't think to take it back -- I just threw it out. Definitely sounds like there was a bad batch.
posted by somanyamys at 6:31 AM on April 11, 2007

So, did you eat it, dame?
posted by amro at 7:23 AM on April 11, 2007

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