Milk Production, Dairy Practices and Value Addition
Milk composition and clean milk
The exam tests milk composition, clean milk production, platform tests, adulteration and value addition. Expect a calculation on fat standardization or a question on why milk spoils.
Core rules and concepts
- Cow milk: about 87% water, 3–5% fat, 8–9% solids-not-fat; buffalo milk is higher in fat.
- Clean milk: wash the udder, discard foremilk, use dry hands and sanitised utensils, cool quickly and filter.
- Colostrum is not sold as normal milk; it is vital for the calf.
- Tests: lactometer indicates density, not fat; Gerber test measures fat; MBRT and clot-on-boiling indicate bacterial quality.
- Value addition: ghee, paneer, curd, lassi, khoa and flavoured milk raise shelf life and income.
- Adulteration tests include iodine for starch and lactometer for added water, but density can be masked by added solids.
Worked example
Standardise 100 kg of 6% fat milk to 4.5% fat using skim milk at 0.1% fat. Pearson square ratio of 6% milk to skim = (4.5−0.1):(6−4.5)=4.4:1.5, so 6% milk = 100×4.4/5.9=74.6 kg and skim = 25.4 kg. The reasoning uses a fat balance, not a guess.
Traps that cost marks
Do not say a lactometer measures fat. Do not sell colostrum as market milk. Do not assume boiling removes adulterants. Do not ignore cooling. Do not standardise by volume without checking density.