It happened again today. A friend of mine got sick (flu-like symptoms, barfing, etc.), and blamed it on food poisoning from a restaurant she went to for lunch earlier the same day. Her assumption isn’t unique: I’ve encountered many people who blame sickness (especially when vomit is involved) on food poisoning, and blame the food poisoning on a meal consumed within the past 24 hours.
I’ve always thought that food poisoning from e-coli, salmonella, and other such critters has a gestation time of several days. So, if it was food poisoning, it was from a few days before, not a few hours.
What’s the straight dope here? Can these bacteria really multiply that fast? Is food poisoning really most likely caused by something eaten in the past day?
Also, there is no such thing as a 24- or 48-hour flu bug. The flu lasts at least 7 days.
If you have a gastrointestinal thing (throwing up and diarrhea) that only lasts a day or two, it’s food poisoning. Happens more often than you think.
Yuck.
“I’ve always thought that food poisoning from e-coli, salmonella, and other such critters has a gestation time of several days. So, if it was food poisoning, it was from a few days before, not a few hours.”
Food “poisoning” from E. coli, salmonella and most other such critters has an incubation time that is generally more than 24 hours. That is because E. coli and salmonella actually set up shop in your intestines and reproduce, making your sick, and that takes some time.
There are other kinds of food poisoning however. The common, fast-acting one is due to staphylococci which don’t reproduce in your intestines but reproduce in contaminated food left too long outside of the refrigerator. As the staph grow, they produce a toxin. When you eat the food, it is the toxin that makes you vomit, etc. Since the bacteria don’t have to reproduce to make you sick, it only takes a few hours before your symptoms begin.
How long a microorganism takes to give you food poisoning depends in very general terms on whether it does so as an infection or an intoxication.
For an infection, you ingest the bugs, they multiply in your gut and thus, by production of some charming biochemicals, invasion and/or sheer numbers, make you sick. For some bugs, there is a critical number you need to ingest for infection to be likely, for others it is the serotype, for others the type of food in or with which they are ingested.
For an intoxication, if a toxigenic bug has multiplied in an appropriate foodstuff (not all toxigenic bugs are equally effective at toxin production in a given substrate) to a sufficient concentration it is likely to have produced an effective level of whichever toxin(s) it produces.
As a VERY broad generalisation, infection tends to take longer than intoxication, in the order of one to many days for symptoms to manifest for infection (thinking E. coli, Salmonella sp, V. cholerae and Hepatitis.), whereas ingestion of the foodstuff and toxin usually has a relatively swift effect - in the order of a half to a few hours. (thinking Staph aureas, B cereus, Clost botulinum, Scombroid poisoning). Tho botulism, depending on the type, can take quite a few days to manifest.
Unless the victim has other predisposing factors, the toxigenic bugs are unlikely to also be infective in the gut. That is, if they didn’t get to the right concentration before ingestion, they are unlikely to take up residence and finish the job off.