Milk + Dairy products Flashcards
1
Q
What are major components of milk?
A
- Water
- Fat
- Protein
- Lactose
2
Q
What are minor components of milk?
A
- Salts
- Citric acid
- Enzymes
- Vitamins
- Gases
- Phospholipids
- Immunoglobulins
3
Q
What is the pH of milk? What can change this?
A
- 6.4 - 6.8
- Decrease in pH = microorganisms if lactose fermenting, extensive lipolysis, increasing temp
- Increase in pH = physiological stress, Decreasing temp
4
Q
What are infectious agents in dairy products?
A
- TB
- Q-fever
- Leptospirosis
- Salmonellosis
- Campylobacter jejuni
- Listeria monocytogenes
- Mycobacterium paratuberculosis
- Staph aureus
5
Q
What are spoilage organisms found in dairy products?
A
- Bacillus sporothermodurans
- Butyric acid bacteria
- Pseudomonas spp
- Streptococcus thermophilus
6
Q
What infectious agents in dairy products can be pathogenic + spoilage organisms?
A
- Bacillus cereus
- Escherichia coli
7
Q
Why should pregnant women avoid soft cheeses?
A
- Listeria - can grow in fridge
8
Q
What standards must raw milk meet?
A
- Plate count < 100,000cfu/ml
- Somatic cell count <400,000 cfu/ml
9
Q
What standard must raw milk intended for direct human consumption meet?
A
- Plate count <20,000 cfu/ml
- Coliforms = <100cfu/ml
10
Q
What is D value?
A
- Time @ given temp required to reduce population by 1 log (90%)
11
Q
What is Z value?
A
- Temp change required to alter D value by factor of 10
12
Q
What does pasteurisation do?
A
- Eliminate Coxiella burnetti
- Min 6 log reduction of Listeria monocytogenes
13
Q
What is regulatory requirement of pasturisation?
A
- > 72oC for minimum of 15seconds
14
Q
A
