By Ilana Korchia
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”.
Of the 165,000 monthly Google searches related to Salmonella, one of the most frequently asked questions is, “Are Salmonella symptoms immediate?” This is a question worth exploring.
Let me introduce you to a key phrase in 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 six 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 three to 70 days. 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 or more hours, or even a few days, ago (unless it’s Staph food poisoning).
To give you a better understanding of incubation periods, I’ve created a handy table.
Pathogen | Bacteria, virus, or parasite? | Typical incubation period |
Botulism (C. botulinum) | Bacteria | 12 to 36 hours |
Campylobacter | Bacteria | 2 to 5 days |
Cyclospora | Parasite | ~1 week |
C. perfringens | Bacteria | 6 to 24 hours |
Escherichia coli (E. coli) | Bacteria | 3 to 4 days |
Hepatitis A | Virus | 2 to 4 weeks |
Listeria | Bacteria | 3 to 70 days |
Norovirus | Virus | 12 to 48 hours |
Salmonella | Bacteria | 12 to 36 hours |
Shigella | Bacteria | 1 to 2 days |
Staphylococcus aureus | Bacteria | 30 minutes to 6 hours |
Vibrio spp. | Bacteria | 1 to 3 days |