Which practice best maintains cold chain integrity for pasteurized milk after purchase?

• A. Letting the milk stand at room temperature until use.
• B. Store milk in a freezer for extended shelf life.
• C. Keeping refrigerated to maintain cold chain integrity and inhibit psychrotroph growth after purchase.
• D. Expose to direct sunlight to kill bacteria.

Answer: (C)

Maintaining the cold chain means keeping milk at a consistently cold temperature from the store to home storage to slow or stop the growth of bacteria that can survive refrigeration. Pasteurization reduces harmful pathogens, but some bacteria known as psychrotrophs can still grow at fridge temperatures. By keeping milk refrigerated, you keep its temperature within the range that minimizes microbial activity, preserving safety and quality and extending shelf life.

Leaving milk at room temperature allows bacteria to multiply quickly, increasing spoilage risk. Storing milk in a freezer isn’t typical for everyday use and can affect texture and thawing behavior, though it can halt growth. Exposing milk to direct sunlight raises temperature and accelerates deterioration. Keeping it refrigerated best preserves the cold chain after purchase.