Lecture 19 Week 11 - Food Safety (Microbial Pathogens)

Question 1

What 3 things classify a food as ‘not safe’?

Answer 1

1. If it is damaged to an extent where its intended use can’t be done
2. If it is from a diseased animal or one that has died (besides slaughter)
3. It is contaminated with biological, chemical or physical (BCP) matter

Question 2

What are examples of biological, chemical or physical (BCP) matter?

Answer 2

B: bacteria, fungi parasites, viruses
C: pesticides, heavy metals, antibiotics
P: glass, plastic, packaging materials

Question 3

How are food borne illnesses monitored?

Answer 3

• Monitor trends
• Detect outbreaks
• Inform preventative measures
• Evaluate efficacy of public health interventions

Question 4

Shiga toxin-producing E. coli (STEC)

Answer 4

Usually harmless but pathogenic strains can cause severe illness.
Main cause of haemolytic uraemic syndrome (HUS) which can be fatal.

Question 5

Sources of STEC?

Answer 5

• Major animal reservoir is ruminants (esp. cattle and sheep)
• Meat may be contaminated if exposed to faecal matter during processing
• Contaminated water for irrigation, soil treated with farm effluent

Question 6

Symptoms of STEC?

Answer 6

Diarrhoea, abdominal cramps, vomiting, fever

Question 7

E. coli O157:H7 outbreak. Where was it found? What did it come from?

Answer 7

Baby spinach. Wild pigs and surface waterways exposed to faeces from cattle and wildlife.
*** Consumer’s trust in all of spinach production diminished

Question 8

Listeria spp. Where is it found? What does it come from? What symptoms does it cause? Any outbreaks?

Answer 8

Comes from: water, soil, vegetation, fodder, wet areas in food, processing facilities, raw (unpasteurized) milk.
Common on sliced deli meats (salty & moist). Is a bacteria that can grow with or without oxygen.
Can cause LISTERIOSIS (flu-like symptoms, high mortality rate).
Rockmelon outbreak.

Question 9

What are the 5 major pathogens that cause illness?

Answer 9

• Campylobacter
• Salmonella
• E. coli
• Listeria
• HAV

Question 10

Salmonella spp. Where is it found? What does it come from? What symptoms does it cause? Any outbreaks?

Answer 10

Salmonella enterica most common. Most outbreaks associated with eggs, poultry, raw meat, milk and dairy. Can cause SALMONELLOSIS
e.g. Packaged lettuce in Australia in 2016 - linked to chicken fertiliser

Question 11

Hepatitis A. Where is it found? What does it come from? What symptoms does it cause? Any outbreaks?

Answer 11

Small virus. Transmitted via the faecal-oral route. Peak before you show any symptoms.

e. g. Frozen berry HAV outbreak - Nanna’s frozen berries
e. g. Coles frozen pomegranate

Question 12

Campylobacter. Where is it found? What does it come from? What symptoms does it cause? Any outbreaks?

Answer 12

Bacteria. Risk food = poultry meat. Self-serve sandwich bar contaminated with raw meat.
e.g. Cucumber outbreak in SA in 1995.

Question 13

How can we get poisoned from fish?

Answer 13

Histamine poisoning (scromboid) - AA histidine --> histamine. Then isn't destroyed by cooking and can induce an allergic response.
Anaphylaxis, hot flushes, headache, hives.

Question 14

What 4 things are looked at when conducting R&D?

Answer 14

1. Better detection methods – current methods are slow
2. Sanitising processes
3. Surveillance, identifying major causes
4. Suppression of pathogens