Fat Globule Size in Homogenized Milk

The size of fat globule in homogenized milk is:

Correct Answer: 2 µm

After homogenization, the fat globule size in milk is reduced to 2 micrometres (2 µm) or less. This makes the emulsion extremely stable and prevents cream from rising to the top.

Homogenization

Homogenization is the process of making a stable emulsion of milk serum and milk fat by forcing milk through a tiny orifice under high pressure (homogenizer). This breaks large fat globules into uniformly small ones.

Effects of Homogenization

• Fat globule size reduced to ≤2 µm (from normal 2–5 µm).
• Cream does NOT rise (no cream line) — stable emulsion.
• Viscosity increases after homogenization (more surface area of fat globules).
• Cannot separate cream from homogenized milk by gravity.
• Milk appears whiter due to greater light scattering by smaller globules.
• More digestible — smaller fat globules are easier to digest.

Normal Fat Globule Size

In normal (non-homogenized) milk: average 2–5 µm; range 0–10 µm.

Why Other Options Are Wrong

• 3, 4, 5 µm → these are within the normal (pre-homogenization) range. After homogenization, size is specifically reduced to 2 µm or below.