bacterial toxins

Staphylococcus aureus intoxication

- One of the most important causes of food-borne disease worldwide.
- It is gram positive, nonmotile and non-spore forming cocci that forms 5entertoxins ( A-SEA, SEB, SEC, SED, SEE)
- Entertoxins are simple proteins that have high heat stability
- Growth increases at optimum pH and temperature
- Foods containing S.aureus at level of 5 X 105/g may cause S.aureus intoxication

Signs and symptoms

- begin 1-6hrs of consumption
- nausea, vomiting, abdominal cramps, diarrhea

Preventive measures

- practice hygiene practices
- reduced post-cooking contamination of high protein foods and eliminating prolonged storage of cooked food at room temp before eating

Clostridium botulinum intoxication

- gram positive rod-shaped anaerobic bacteria capable of forming heat resistance spores
- 6types of heat labile neurotoxins : A, B, C, D, E, F and G
- Type A and B : more likely to cause botulism in humans
- Example of food containing type A and B: beans and corns
- Type E : isolated from soil, seawater, fish intestines and sea or lake sediments
- Type F : from liver paste
- Botulinum toxin is a super toxin compound.
- Prevention : heating at 79oC for 20mins or at 85oC for 5mins

Signs and symptoms

- Appears 12-24hrs following consumption
- headache, blur vision, dizziness
- causes death from periods 24hrs to 2-3weeks

Preventive measures

- proper home preservation of foods
- discard all swollen and damaged canned products

Bacillus cereus intoxification

- gram positive, rod shaped, spore forming aerobe
- found in cereals, milk, herbs and spices
- 2types of enterotoxins : emetic and diarrheagenic
- Diarrheagenic toxins is a protein that is produced by actively growing cells
- Activated by enzymes like trypsin or exposure to 56oC or more than 30mins
- Emetic toxin is stable to heat, pH and pepsin enzymes

Clostridium perfringens intoxication

- causes foodborne infections followed that subsequently lead to sporulation
- lecithinase, an enterotoxin released during sporulation
- five antigenically (toxicologically) types: type A through E
- type A: involve in foodborne gastroenteritis in humans
- type C: produces 2 different toxins; lethal-necrotizing and hemolytic



book: introduction to toxicology and food