Table 1.
Factors affecting Staphylococcus aureus growth and enterotoxin formation4
| Factor | Optimal growth | Growth limits | Optimal SE production | SE production limit | Enterotoxin (s) reported affected | Notes to effect(s) on enterotoxin production | Examples of analysis of the specific factor in food products | References |
| Temperature | 35–41°C | 6–48°C | 34–40°C | 10–46°C | SEA, SEB, SEC, SED | Temperature seems to affect enterotoxin synthesis more that growth. | Milk Ham Egg products |
44, 141–144, 169 |
| pH | 6–7 | 4–10 | 7–8 | 5–9.6 | SEA, SEB, SEC, SED, SEE | Higher tolerance under aerobic compared with anaerobic growth conditions. Lactic acid particularly inhibits toxin formation. agr dependent regulation (SEC). |
Ham Sausage |
7, 75, 143–147, 169 |
| aw | 0.99 | 0.83 ≥ 0.99 | 0.99 | 0.86 ≥ 0.99 | SEA, SEB, SEC, SEH | SEB and SEC may be more sensitive than SEA and SEH. SEH enterotoxin production at aw: 0.97 > 1 > 0.95. |
Cured beef slurry Cured pork slurry Bacon Scrimp slurry Sausage |
85, 90, 96, 142, 147–152 |
| NaCl | 0% | 0–20% | 0% | <12% | SEA, SEB, SEC | Raises temperature limit for SEA production. Low osmolality increases enterotoxin production. SEB production seems more strongly inhibited than growth. |
Ham Sausage |
85, 88, 96, 144, 153–156, 169 |
| Oxygen | Aerobic | Anaerobic-aerobic | Aerobic | Anaerobic-aerobic | SEA, SEB, SEC, SEH | Increases yield of SEB up to 10-fold. 10% dissolved oxygen is optimal for SEB production. |
Ham Prawn Sausage |
98, 113, 157, 158, 159, 160, 161 |
| Redox potential (Eh) | >+200 mV | ≥200 to > +200 mv | >+200 mV | ≥100 to > +200 mv | - | - | - | - |
| Lactococcus lactis | - | - | - | - | sec, sel (sek, seg, seh) | Strongly reduces transcription of sec and sel and sightly sek, seg, seh | Cheese | 6, 107, 162 |
| sea | May favor the maintenance of sea in stationary phase. |