curedmeat.com / Safety / Hazards

Staphylococcal enterotoxin

Staphylococcus aureus

Grows at a lower water activity than the other pathogens, and produces a heat-stable toxin. Cooking the product afterwards does not remove the toxin.

Controls, with the source for each

Degree-hours. 60 F is given as the critical temperature at which staphylococcal growth effectively begins. FSIS considers meeting degree-hours to limit growth to 2 logs or less, citing Smith and Palumbo 1978.

Water activity, in air. ICMSF gives the aerobic growth limit as 0.83; FSIS recommends 0.85 taking the other hurdles in a cured product into account.

Water activity, vacuum packed. ICMSF gives the anaerobic growth limit as 0.90.

Brine concentration after equalisation. Generally, a 10 percent brine concentration following equalisation will prohibit S. aureus enterotoxin production when the temperature is increased during drying.

Why it matters here

S. aureus is the organism that decides whether a dried product is shelf stable, because it is the one still able to grow when everything else has stopped. It is also why fermentation is timed rather than simply performed: a slow acidification is a long window in which this organism has the field to itself.

Notes

• The toxin, not the organism, is the hazard. A product that grew S. aureus and was then heated is a product with heat-stable toxin in it.

Steps that bear on this hazard

• Dry curingSalt and curing salts applied to the surface of a whole musc
• Fermentation with starter culturesLactic acid bacteria acidify the meat, and where staphylococ
• Air dryingWater leaves the product until its water activity is low eno
• Equalisation and restingThe product is held, wrapped or unwrapped, while the cure di

FSIS guideline identifiers and their URLs are listed on the methodology page. CFR citations are to the Electronic Code of Federal Regulations, Title 9, as in force on 1 January 2026.