Which of the following factors does NOT contribute to milk's shelf life?

The factor that does not contribute to milk's shelf life is color. While color can be an indicator of certain quality aspects, such as freshness or potential spoilage, it does not inherently influence how long milk can be stored without deteriorating.

In contrast, pasteurization plays a crucial role in extending milk's shelf life by eliminating harmful bacteria and pathogens that can cause spoilage. Packaging is vital as it protects the milk from light and air exposure, both of which can lead to spoilage. Storage temperature is equally important; keeping milk at the appropriate cool temperatures slows down the growth of bacteria and helps maintain its quality over time. Thus, while color may provide some insight into the milk quality, it does not affect the storage life of the product itself.