ICAR AICE-JRF/SRF Dairy Pathogens, Toxins & Microbial Risk: practice questions

1 · Food infection, intoxication and toxi-infection · easy

Botulism typically appears after about:

1. 6 months
2. 30 minutes
3. 3 weeks
4. 12 to 36 hours

2 · Listeria monocytogenes in dairy products · medium

Which groups are most at risk of severe listeriosis?

1. People with lactose intolerance
2. Pregnant women, newborns, the elderly and immunocompromised
3. Healthy adult men aged 20 to 40 years who exercise regularly
4. Athletes in training

3 · Salmonella and pathogenic Escherichia coli · hard

Why is Salmonella a hazard in milk powder despite being killed by heat?

1. It survives long in dry products after post-drying contamination
2. It grows rapidly in powder at aw 0.2
3. It is added with lactic cultures
4. It forms heat-resistant spores during spray drying of the concentrate

4 · Staphylococcus aureus enterotoxins · medium

Staphylococcal food poisoning mainly causes:

1. Meningitis
2. Bloody diarrhoea with HUS
3. Paralysis
4. Sudden nausea and vomiting

5 · Campylobacter, Yersinia and Cronobacter · medium

Cronobacter sakazakii is especially resistant to:

1. Acid at pH 2
2. Drying
3. Pasteurisation
4. Freezing at -18 degrees Celsius

6 · Campylobacter, Yersinia and Cronobacter · easy

Campylobacter is readily killed in milk by:

1. Pasteurisation
2. Refrigeration
3. Freezing
4. Homogenisation

7 · Raw milk and raw milk cheese risks · hard

Which raw milk cheeses are regarded as low risk?

1. Soft surface-ripened cheeses eaten young
2. Any raw milk cheese eaten within one week
3. Fresh high-moisture cheeses such as queso fresco made the same day
4. Hard, long-ripened cheeses such as Parmigiano Reggiano

8 · Raw milk and raw milk cheese risks · medium

In much of South Asia, what practice gives protection similar to pasteurisation?

1. Adding sugar to milk
2. Boiling milk at home
3. Drinking milk warm from the cow
4. Storing milk at room temperature

9 · Raw milk and raw milk cheese risks · medium

Which group should particularly avoid raw milk?

1. Professional athletes
2. Adults with lactose tolerance
3. Pregnant women and young children
4. People with normal immunity only

10 · Microbial risk assessment and the ICMSF approach · medium

Using P = 1 - exp(-r x dose) with r = 0.0001, what is the probability of illness from 1,000 cells?

1. About 0.905
2. About 0.001
3. About 0.1 exactly
4. About 0.095