The shelf life of milk is the number of days it retains a desirable taste flavor when held at refrigerated temperatures. Temperature is critical to maximize shelf life. While the legal maximum at which pasteurized fluid milk may be held is 45 degrees Fahrenheit, it should be held below 40 degrees Fahrenheit to increase shelf life.
The generation time of any bacteria that may be in the product is critical. Bacteria that can grow at refrigerated temperatures, called “psychrotrophs,” are bacteria capable of rapid growth at refrigeration temperatures. They will grow faster as the temperature is increased.