Questions 38-44

Question 1

On which various contamination pathways microorganisms might enter the food production and processing chain?

Answer 1

Food production:

• Animals (primary contamination, feedstuff)
• brewing and cleaning water
• faeces/ingesta
• soil, animals (pests)
• humans (staff)
• objects/ surfaces

Food processing:

• humans (staff)
• objects/ surfaces, machinery
• animals (pests)
• ingredients
• cooling and cleaning water

Question 2

General properties of endotoxins?

Answer 2

• Excreted proteins
• Generally heat labile
• Specificity by binding onto cellular receptors: Cytotoxins, Enterotoxins, Neurotoxins
• Some highly toxic, fatal
• Strong immunogenic, induction of neutralising antibodies

Question 3

What are general properties of Exotoxins?

Answer 3

• Lipopolysaccharide- Lipoproteincomplexes of Gram-negative bacteria
• Very heat stable
• Systemic effects: Fever, headache
• Weakly toxic, rarely fatal
• Weakly immunogenic, no protective immune response

Question 4

Please define the terms infection, intoxication and toxi-infection

Answer 4

Infection: Ingestion of pathogenic organisms that grow and cause illness
- Salmonella, Norovirus (?)

Intoxication: Illness caused by the ingestion of toxins
- Cl. Botulinum, S. aureus, B. cereus

Toxi-infections: caused by bacteria getting into the body and releasing harmful toxins; can cause toxic shock syndrome
- Cl. Perfringens, EHEC, Campylobacter

Question 5

Please list three possible health impairments for livestock and three effects on food or the final consumer which might be caused by feeding spoiled feed.

Answer 5

Health impairments for livestock:
- Acute gastroenteritis (bacterial enterotoxins)
- Allergic reactions (polysaccharids and proteins of microbial origin)
- Deficiency of vitamins and/or amino acids (microbial degradation or conversion)
- Bacterial overgrowth with disturbance of physiological gut flora

Effects on food: change in sensorical properties (look, colour, consistence, odour, nauseating properties)

Effects on final consumer (human):
- Intoxication (S. aureus, Cl. Botulinum), toxi
- Toxi-Infection (Cl. Perfringens, EHEC), infection (Salmonella, Norovirus)
- Allergic reactions
- Infection with virus, fungi or parasite
- Long term damage from toxins like mycotoxins