Lab exam of sour milk products

Question 1

Sensory evaluation assess the:

Answer 1

Colour
Taste
Odour
Consistency
Overall acceptability from 1 to 9

Question 2

Evaluation of packaging:

Answer 2

Defects, attractiveness, identity, marketing

Question 3

Defects in fermented milk products:

Answer 3

Appearance:
- separation due to insufficient fat, heat treatment, pH, temperature, contamination
- unclean - moulds and dirt
- fermented - yeasts and coliform organisms

Flavour defects:
- old raw milk, contamination, too low acidification, poor milk quality, too high protein

Texture defects:
- separation (high acidification), split/cleavage

Unsuitable milk&yoghurt culture, inactive culture, flavour, storage temperature

Question 4

How to distinguish bacteria:

Answer 4

Feeling gas bubbles in mouth (coliform bacteria)
Bloated packing
Consistency
High amount of liquid
Moulds

Question 5

Flow diagram:

Answer 5

Preparation of the basic mix
Homogenization
Heat treatment of the milk
Cooling
Inoculation of a starter culture
- incubation in retail cartons, cooling to 4C - SET YOGHURT
- incubation in bulk, agitation, cooling to 15-20C, packing, cooling to 5*C - STIRRED YOGHURT

Question 6

Methods of examination:

Answer 6

Gerber method: fat by butyrometer
Determination of pH of the milk to form yoghurt (4.5)
Determination of titratable acidity in yoghurt (not exceed 75SH)