Pasteurization: “Pasteurized” means that the milk has been heated to a minimum of 161°F for a minimum of 15 seconds or 145°F for 30 minutes (for equivalent kill of bacteria), and packaged under clean and sanitized conditions. Some bacteria survive pasteurization, most often in very low numbers, though they are not considered harmful and will generally not spoil milk under normal refrigerated holding conditions and times. Spoilage of pasteurized milk before its time is most often caused by bacteria that contaminate the milk after the pasteurization process and/or from improper refrigeration. Most dairy processors prevent this type of contamination, though it still occurs at times due to errors at the processing plant. Typical spoilage bacteria found in milk do not cause disease or illness, although the consumer will often find spoiled product to be offensive. A few types of bacteria are that survive pasteurization can eventually spoil milk, but this generally occurs later in shelf-life (past code). The shelf-life of pasteurized milk held under proper refrigeration, defined as less than 45°F, can range from 12 to 21 days post processing. Holding pasteurized milk at temperatures above 45°F will shorten the shelf-life dramatically; the colder the milk the longer it will last, the warmer the milk, the quicker it will spoil. Ideal storage temperatures for milk and dairy products are 34-38°F. Under ideal refrigeration, most pasteurized milk will remain fresh for 2-5 days after its sell-by date. Once opened, pasteurized milk should be used as soon as possible for best quality and taste.