46. Foodborne diseases resulting from biological food contamination. Prevention.

Define food‑borne disease.

An infectious or toxic illness caused by agents that enter the body through ingestion of contaminated food.

Name four high‑risk groups for food‑borne illness.

• elderly

• young children,

• pregnant women

• people with weakened immunity.

List the two main pathways of biological food contamination.

• Exogenous (contamination during processing, packaging, transport)

• Endogenous (animal was already infected).

Which bacterium is the most common cause of food‑borne illness?

Campylobacter spp.

Name four other frequent agents of food poisoning.

• Salmonella

• Staphylococcus aureus

• Clostridium perfringens

• Norovirus.

Toxicoinfection

• requires ingestion of large numbers of live bacteria that then release toxin.

Pathogens enter the body via food, multiply in the gut, and produce toxins there

Intoxication

results from ingesting pre‑ formed toxin only.

Definition: Illness caused by preformed toxins in food (no need for bacteria to grow in the body)

Mycotoxin Intoxication

Illness caused by toxins from fungi (moulds) in contaminated food

Food-Borne Infection

Caused by ingestion of pathogens that then invade or infect the host

Give one example each of:

• Food‑borne toxicoinfection

• Food‑borne intoxication

• Mycotoxin intoxication

• Food‑borne infection

• Toxicoinfection: Salmonellosis

• Intoxication: Botulism or staphylococcal food poisoning

• Mycotoxin: Aflatoxicosis (from Aspergillus toxins)

• Infection: Typhoid fever, shigellosis, viral hepatitis

Incubation period of salmonellosis?

6–24 h.

Three leading clinical syndromes of salmonellosis.

Gastroenteritis, lower dyspeptic syndrome, general intoxication syndrome.

Key prevention measures for salmonellosis.

Veterinary oversight, strict kitchen hygiene, refrigeration, thorough cooking, good food‑handler hygiene.

Incubation time for staphylococcal intoxication.

1–6 h.

Why doesn’t reheating always make contaminated food safe in staph poisoning?

S. aureus enterotoxins are heat‑stable

• survive cooking temperatures.

High‑risk foods for S. aureus toxins.

Meat, poultry, creamy salads, bakery fillings, dairy, high‑starch or high‑salt foods.

Principal foods linked to botulism.

Improperly canned vegetables, mushrooms, smoked fish, jarred foods; honey (infant botulism).

Three classic symptom stages of botulism.

1) Blurred vision & GI upset;

2) Descending paralysis (ptosis, respiratory muscle weakness);

3) Failure of cardio‑respiratory centers.

Prevention of botulism.

• Proper canning/boiling,

• discard bulging cans,

• no honey for infants < 1 yr,

• public education.

Which fungus makes aflatoxin B₁ and why is it concerning?

• Fungus: Aspergillus flavus

• Concern: Aflatoxin B₁ is a potent hepatotoxin and liver carcinogen, especially linked to hepatocellular carcinoma.

• It contaminates grains, nuts, and stored foods in warm, humid conditions.

Optimal grain storage conditions to prevent aflatoxins.

Moisture < 10 %, cool temperature, good ventilation.

Name two other toxigenic fungi and their toxins/effects.

• Fusarium graminearum → Trichothecenes

  • Effects: Gastrointestinal irritation, immune suppression
    

• Claviceps purpurea (ergot) → Ergot alkaloids

  • Effects: Vasoconstriction, can lead to gangrene and convulsions (known as ergotism)

list five universal food‑safety practices.

1. Keep raw and cooked foods separate.

2. Cook foods to safe core temperatures.

3. Chill perishables promptly (≤ 4 °C).

4. Use safe water and raw materials; reject damaged cans.

5. Maintain personal hygiene of food handlers (hand‑washing, no open wounds).