I recently bought a pre-packaged bag of brussels sprouts. The sprouts in the bag looked great, green and plump with not a spec of black or brown on them. The next day I cut open the bag and found that the entire bag smelled like a mix between vinegar and over-ripened cantaloupe. If I cut open a single sprout the smell was even stronger.

There was no evidence of spoilage or a mushy texture, all the raw sprouts were firm.

I have eaten and cooked brussels sprouts many many times before so I am familiar with their normal cabbage-like or sulfurous scent. These sprouts were not like that, it was a strong sour smell.

I tried cooking with them and the smell never went away after either boiling or roasting. They also tasted like they smelled.

Does anyone know what could have happened? Was there some kind of chemical involved?

  • Was these packed with protective atmosphere? Maybe washed in something before packaging? What was written on package? And what was "best before" date? As far as I know (and that's not far) both atmosphere and washes are designed to prolong "sellability" first, health safety second, and taste & smell last.
    – Mołot
    Commented Jan 5, 2017 at 9:38
  • @Molot The expiration date was at least a month away. I've since thrown out the package so it will be a little bit before I can find any info about the washes/packaging
    – MeltedPez
    Commented Jan 5, 2017 at 16:36

1 Answer 1


What you are describing is what we call a food that has "soured". (This is what I was taught growing up.) The food looks and feels perfect but has that awful sour odor.

In my experience it is from improper storage, usually from foods being kept too warm or not getting enough air circulation. (Not necessarily by you, but somewhere along the transport chain.)

I have found it in both Brussels sprouts and broccoli. I have even bought broccoli, used some of it, and later taken the rest out only to find it soured. Or bought Brussels sprouts and kept them for a couple of days before using and found that they had soured. This says to me that the souring process had already started.

Additionally, I have had it happen with fresh corn that was left on my porch in warm weather.

I have also found it in bagged salads and spinach. With those, a good washing and fresh air sometimes gets rid of the odor - but not always.

Unfortunately, we don't always know how foods have been handled and stored before we buy them.

I have searched extensively to find out more about this, to no avail. I can find information about how to tell if food is going bad or rotting, but this is a totally different thing. You have no way of knowing that this souring process is happening. That is, until you smell it.

  • 2
    Not meaning to start a "war"; just an innocent observation from another direction, but I never heard, growing up or since, of food that had "soured" (except dairy products of course.) In our family a vegetable was either rotten (or on its way there), or it was good. We did not have the concept of "soured". My location being Calif, USA., it seems fascinating that in a lifetime of eating, cooking, picking, and observing vegetables, our two -- "micro-cultures" (?) have developed differing understanding of how they behave. [FWIW]
    – Lorel C.
    Commented Jan 5, 2017 at 16:12
  • 2
    @LorelC. No "war". :) I know people who have observed this and I know others who haven't. This is entirely different than a vegetable or other food rotting/going bad. I don't know the science behind it, thus the attempts to research it. Also, I don't know if the term "sour" is scientifically correct or if it came into use because of the sour smell. However, I assure you that it exists. If you haven't experienced it, consider yourself lucky.
    – Cindy
    Commented Jan 5, 2017 at 21:08
  • 1
    @LorelC. I don't know. It's an extremely unpleasant odor. I've never known anyone to eat anything with that smell. I was always told that the food wasn't good and it was tossed. Again, nothing scientific. I've wondered if there might be some type of fermentation going on but can't find anything about it. But I would think that fermentation would affect the look and texture.
    – Cindy
    Commented Jan 5, 2017 at 21:34
  • 1
    @LorelC., as a Spaniard I also never experienced (or rather paid attention to) the souring . But then I moved to Poland and turns out that pickling/fermenting is a traditional way to prepare some dishes: kapusta kiszona, [ogórek kiszony] (en.wikipedia.org/wiki/Pickled_cucumber#Polish) (and it can be delicious!). The german sauerkraut is also about this: fermented cabbage. "Various lactic acid bacteria" generate lactic acid, which causes the sourness. So, probably in fact you have experienced this in soured milk, yogurt, etc.
    – hmijail
    Commented Jan 8, 2017 at 22:46
  • 1
    @hmijail : it's also possible that it's regional because of types of bacteria in the region or climate (going sour slowly vs. quickly as they're at different temperatures). And as you mention sauerkraut -- cabbage, broccoli and brussel sprouts are all related, and the process is just leaving it to sit (in an anaerobic environment). Cabbage leaves are also used for making a local sourdough starter, as they catch wild yeast as they grow.
    – Joe
    Commented Sep 17, 2017 at 13:26

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