I think I’ll talk about Salmonella in my next few posts. Wondering why? Well, I recently discovered that the search volume — or the number of monthly searches — for “Salmonella” is nine times greater than that of “foodborne illness.” The more you know.

Of the 165,000 monthly Google searches related to Salmonella, one of the most frequently asked questions is, “Are Salmonella symptoms immediate?” A question worth exploring.

Let me introduce you to a key phrase in my world — the world of food safety: incubation period. The incubation period is the time it takes for a person to become ill (i.e., develop symptoms) after consuming a contaminated food product. Different pathogens have different incubation periods.

For Salmonella, the incubation period typically ranges from 12 to 36 hours, though it can be as short as 6 hours or as long as one or two weeks. This relatively short incubation period stands in contrast to Listeria, another bacterium, which has an extremely variable incubation period spanning from 3 to 70 days. Hence why I often advise my clients that what made them sick might not be the last thing they ate before symptoms appeared; it is more likely something they consumed 12+ hours, or even a few days, ago, unless it’s Staph food poisoning.

To give you all a better understanding of incubation periods, I’ve created a handy table. I hope you find it helpful.

PathogenBacteria, virus, or parasite?Typical incubation period
Botulism (C. botulinum)Bacteria12 to 36 hours
CampylobacterBacteria2 to 5 days
CyclosporaParasite~1 week
C. perfringensBacteria6 to 24 hours
Escherichia coli (E. coli)Bacteria3 to 4 days
Hepatitis AVirus2 to 4 weeks
ListeriaBacteria3 to 70 days
NorovirusVirus12 to 48 hours
SalmonellaBacteria12 to 36 hours
ShigellaBacteria1 to 2 days
Staphylococcus aureusBacteria30 minutes to 6 hours
Vibrio spp.Bacteria1 to 3 days

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