Which of the following is NOT identified as a contamination route for milk after leaving the cow?

• A. Mastitis
• B. Systemic disease (Bovine TB)
• C. Refrigeration
• D. Skin microflora

Answer: (C)

The key idea is distinguishing ways pathogens can enter milk after it leaves the cow from steps that prevent contamination. Mastitis introduces bacteria directly into milk because the udder is infected, so that milk becomes contaminated as it’s produced. Systemic disease, like bovine TB, can shed organisms into milk, making it a potential contamination route if the animal has the disease. Skin microflora from the teat skin or from milking equipment can contaminate milk if hygiene isn’t maintained.

Refrigeration, on the other hand, is a preservation step that slows or stops the growth of microbes. It does not introduce contamination; it helps keep milk safe by limiting microbial proliferation. So refrigeration is not a contamination route.