practical notes on examination of dairy ice-cream in the laboratory including the sampling and equipment

1. Practical Notes on
Dairy products
1

2. Ice cream
Practical examination (5)

3. Def: Dairy products obtained from milk or cream describe a frozen product.
Types: 1- Dairy ice cream (milk solids, sugars, stabilizers, emulsifiers, flavoring agent)
2- milk ice (milk solids, without additions of foreign fat)
3- water ice (diluted fruit juice, sugars, stabilizers, flavoring agent)
sorbetwater icemilk iceIce creamingredient
2-410Fat%
4-1211Milk SNF%
25301313Sugars
68.569.570.565water
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
emulsifiers
stabilizers

4. Sampling of ice-cream
Precautions:
-Keep samples frozen till arrival the lab.
-Add dry ice in the icebox.
- start the examination within 36h after collection preserved at -4c.
Sampling equipment
Should be sanitized immediately before before use
-Semi frozen: (soft served) take about 60gm by stainless steel dipper.
- frozen product: ( hardened ice- cream) by sanitized knife or spatula or Trier.
Sampling procedure
- Un opened packages sent to the lab.
Samples from vat container(250-500gm) from different sizes.
-prevent thawing and refreezing of frozen dairy products.

5. Sampling preparation
For chemical analysis
Left at room temperature for
1htill be softened
For microbiological analysis
In water bath 45c /15min.by
holding in sampling jar
1- Physical examination
Sampling examination
-Signs of abnormal flavour
- abnormal color
- growth of yeast or mold
- abnormal taste (grittiness, sandiness)
-Fat% by rose gottelib method.& gerber method
- moisture % by evaporation method
- coloring matter and gelatin as in cream.
- MBRT
2- Chemical examination
3- Sanitary &Keeping quality examination

6. used to detection the sanitary condition under which the ice
cream produced.
procedures
MBRT Test
1- in sterile cotton plugged test tube add 2ml prepared ice cream .
2- add 1ml methylene blue , standard solution.
3- put in water bath at 37 c then examine each 30min for decoloization.
Result &judgment MBRTGrade
Decolorized in 4 hours or more1
From 2.5-4h2
From 0.5-2h3
Less than 0.5h4

7. Thank you for attention
Presented by :
Dr. Dina A. B. Awad
Lecturer of food hygiene department
Faculty of veterinary medicine
Benha university , Egypt