Staphylococcus aureus

Family Staphylococcus

Staphylococcaceae

Gram ± Staphylococcus

Positive

Shape Staphylococcus

Coccus (grape like cluster)

Growth temperature Staphylococcus

7-48 C (mesophile)

Minimum water activity Staphylococcus

Very salt tolerant, 0.83 needed fro growth

Halotolerant

(An)aerobic? Staphylococcus

Facultative anaerobic

Sporeformer? Staphylococcus

No

Survival Staphylococcus

• Considered poor competitor in microbial environments

• Can survive on stainless steel surfaces for many hours; higher initial concentrations lead to longer survival times

Disease Staphylococcus

• Foodborne intoxication

• Illness is caused by a heat stable toxin produced directly in the food by 50-70% of strains

• This occurs mostly in protein rich food with not much competing flora and a temperature above 15C

Symptoms disease Staphylococcus

• Mild symptoms

• Mostly vomiting

• Incubation time: 0.5-6 hours

  • Duration: 1-2 days

Sources Staphylococcus

• Often associated with solid foods that involve manual processing steps

• Requires additional growth in food for toxin production if the initial contamination level is low.

• Growth and toxin production are facilitated by temperature abuse, protein-rich foods with limited microbial competition, and heated foods that are recontaminated.

• Can be found in salted meats (aw, min = 0.83) and salmon

Reservoir Staphylococcus

• Skin of animals and humans

• 20-50% of humans are carrier of S. aureus

Prevention and control Staphylococcus

• Good hygiene practices are critical fro prevention particularly given its association with manual handling

• Controlling temperature abuse

Optimum pH and pH resistance for Staphylococcus aureus

5-8