Question

Milk cans are generally fabricated from

• A. Copper
• B. Brass
• C. Aluminium
• D. Bronze

Hint:

Aluminium and stainless steel are the preferred materials for milk contact surfaces because they are corrosion-resistant and do not catalyze lipid oxidation, unlike copper and copper alloys.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Materials used for fabricating milk storage and transport containers must meet strict food-grade sanitary standards.
The material must be non-toxic, non-reactive with milk constituents, resistant to corrosion from milk and cleaning chemicals, and mechanically durable.

Step 2: Detailed Explanation:
Let us evaluate the suitability of the metals listed for milk can fabrication:
1. Copper and Brass (Copper alloy): Copper is an active catalyst for lipid oxidation.
Even trace amounts of copper can catalyze the oxidation of milk fat, leading to oxidized, metallic, or cardboard-like off-flavors.
Therefore, copper and brass are avoided in milk contact surfaces.
2. Bronze (Copper-tin alloy): Similar to copper, bronze can catalyze lipid oxidation and is not used for milk contact surfaces.
3. Aluminium (or Aluminium alloys): Aluminium is widely used to fabricate milk cans.
It is lightweight, which reduces transport costs, and has a high strength-to-weight ratio.
It is also highly resistant to corrosion by milk and can form a protective oxide layer that prevents chemical reactions.
It does not catalyze fat oxidation or affect the flavor of milk.
Modern sanitary milk cans are typically fabricated from anodized aluminium alloys or tinned mild steel.

Step 3: Final Answer:
Therefore, milk cans are generally fabricated from aluminium.