**Core Concept**
Pasteurization is a process used to kill harmful microorganisms in milk by applying heat for a specific duration. This technique is crucial for ensuring the safety and shelf life of milk products.

**Why the Correct Answer is Right**
Pasteurization involves heating milk to a temperature of at least 161°F (72°C) for 15 seconds or 145°F (63°C) for 30 minutes. The correct method of pasteurization for milk is boiling at 161°F (72°C) for 15 seconds. This temperature and time combination effectively kills bacteria such as Listeria monocytogenes, Campylobacter, and Salmonella, making milk safe for consumption. The high temperature denatures the proteins and disrupts the cell membranes of the bacteria, ultimately leading to their death.

**Why Each Wrong Option is Incorrect**
**Option A:** Boiling milk at a lower temperature for a shorter duration is insufficient to kill all bacteria and may not completely inactivate the pathogenic organisms.
**Option B:** Pasteurization does not involve cooling the milk immediately after boiling; the milk needs to be held at the desired temperature for a specified period to ensure all bacteria are killed.
**Option C:** Pasteurization is not achieved by simply heating milk to a specific temperature without considering the duration of exposure.

**Clinical Pearl / High-Yield Fact**
It is essential to note that pasteurization does not eliminate all bacteria in milk, including beneficial bacteria, but it significantly reduces the risk of bacterial contamination. This process is a crucial step in ensuring the safety of milk and dairy products.

**Correct Answer:** D.