Question

What is the primary source of aflatoxin contamination in raw milk?

• A. Contaminated water
• B. Improper storage conditions
• C. Inadequate cleaning of milking equipment
• D. Fungal growth in animal feed

Hint:

Remember the metabolic pathway:
\[ \text{Aflatoxin B}_1 \text{ (in moldy feed)} \rightarrow \text{Metabolism in Cow} \rightarrow \text{Aflatoxin M}_1 \text{ (excreted in milk)} \]

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Aflatoxins are toxic, carcinogenic secondary metabolites produced by certain molds, particularly Aspergillus flavus and Aspergillus parasiticus.

Step 2: Detailed Explanation:
- When dairy animals consume feed (such as grains, silage, or oil cakes) contaminated with Aflatoxin B\(_1\) due to mold growth, the toxin is metabolized in the liver.
- This metabolic process converts Aflatoxin B\(_1\) into its hydroxylated form, Aflatoxin M\(_1\).
- Aflatoxin M\(_1\) is then excreted directly into the raw milk.
- Thus, the primary source of aflatoxin contamination in milk is the ingestion of feed contaminated with fungal toxins, rather than water quality, milking equipment, or raw milk storage conditions.

Step 3: Final Answer
The primary source of aflatoxin contamination in raw milk is fungal growth in animal feed.