Will spoiled food always make you sick?
Kind of a strange question, but say something has spoiled, i.e. smells bad, tastes bad, etc.
Will it actually always make you sick? Like for instance spoiled dressing, let's say it tastes sour, smells nasty and you eat it, will it make you sick?
If so what actually makes you sick? The toxins/bacteria? or it just being unappetizing?
I ask because I tried a TINY bit of ranch and while it tasted mostly fine (it was a bit tangy) it smelled quite tangy but looked fine. I also saw this article about people eating bad food and not getting sick.
Ranch dressing is made from buttermilk and so is supposed to have a sour smell and taste. Does the dressing smell worse than when you bought it or is the the first time you've sampled it?
What most people don't get when it comes to food safety: Spoiled food has a chance of making you sick.
When food is visibly spoiled, it has large bacterial colonies growing in it. This means that it has been exposed to conditions which were promoting bacterial growth. Anything which was present on your food will have grown, unless outcompeted by something else.
The bacteria which make food gross are rarely the ones which make you sick. But if they had the chance to grow, the real pathogens had a chance to grow too. If they were present, then they grew, and you will consume them, together with whatever waste products their colony produced.
Assuming that there were infectious bacteria on your food, you will ingest them. From there on, it depends on a ton of factors whether you will get sick or not - the amount you ate, the acidity of your stomach contents, the state of your immune system. The last does not mean "you'll only get sick if you're immunocompromised" - it is like being around a person with the flu, even if your immune system is intact, you can still catch it.
There are pathogens which cannot infect you, but simply produce toxins. Botulinum is the poster child for these, but I think B. cereus also works through a toxin. In this case, eating the food poisons you. Depending on the type and amount of toxin ingested, as well as the current state of your body again (mostly liver function), the symptoms can run the entire spectrum from "so weak you don't notice them" to "you die despite being correctly diagnosed and treated".
Then there are a few more exotic possibilities, for example Hep C cannot cause liver cancer alone, but it does so (sometimes) in the presence of a type of toxin produced by moulds. But this is not actually considered foodborne illness any more, even though it's possible that eating mouldy food was the trigger. It falls outside of the scope of food safety, as the fault cannot be pinned on a specific dish you ate. Nevertheless, it's one more reason to not eat spoiled food.
There is also the possibility that your spoiled food has no pathogens at all, and the spoilage microbes outcompeted all the bad guys, and then of course nothing happens.
So, to sum it up: if you eat spoiled food, there are four possible outcomes:
- You get sick (right away or with an incubation period of 2-3 days) and notice it
- You get sick (right away or with an incubation period of 2-3 days) but the symptoms are so weak you don't even notice it
- You get a different health problem, soon after eating or even years later, without knowing that it was the spoiled food which caused it
- Nothing happens.
There is no way to predict which one will occur. Actually, these outcomes are possible with any food you eat, including safe food, but eating unsafe food increases the probability of the first outcomes a lot, and eating spoiled food increases it even more.
Most bacterial pathogens require an incubation period after being ingested before symptoms show up. You might not get sick until the next day or even days later. This is why outbreaks can be hard to trace back to their source. People tend to blame what they just ate but really it was something they ate a couple of days ago.
@RossRidge good point, I'll update it. Although the incubation period is rarely too long - my memory says 48 to 72 hours, do you have better data?
@rumtscho Compared to what people *think* the incubation period is ("I ate at this restaurant and then I got really sick!"), two days is quite a long time.
According to the CDA it seems to vary a lot. For symptoms to appear: 12-72 hours for salmonella, 6-24 hours for clostridium perfringens, 2-5 days for campylobacter, 1-10 days for E. coli O157:H7. http://www.cdc.gov/salmonella/general/index.html http://www.cdc.gov/foodsafety/clostridium-perfingens.html http://www.cdc.gov/nczved/divisions/dfbmd/diseases/campylobacter/ http://www.cdc.gov/ecoli/general/index.html
The moral of the story is: Don't ever assume that what you just ate was what caused you to get sick, and as a corollary, don't assume that you're "in the clear" if you manage to get through the night after eating something unsafe. Food poisoning isn't just *hard* to trace, it's basically impossible, and most people have dangerously wrong ideas about how accurately they can identify the cause.
*"Assuming that there were infectious bacteria on your food.."* - It's not a question of "if", it's a question of "how many". There's *always* going to be infectious bacteria on your food *(and on your skin, in the air, etc)*.
@BlueRaja-DannyPflughoeft I thought of writing that, then realized it's an overgeneralization. With bacteria friendly food like meat, the assumption is true, the thing you have to cross your fingers about is not to get a MRSA from it. But if you think of a piece of hard candy, it does not come from a rich breeding ground for pathogens, and the ones which happen to find it die soon. So it's completely possible to find a piece of food which does not have pathogens in the moment you eat it. We hope the eater washed his hands, of course.