http://www.nytimes.com/2016/09/27/science/organic-milk-shelf-life.html 2016-09-26 20:49:30 Organic Milk Will Wait and Wait for You A different, hotter pasteurization process helps explain why organic milk has a longer shelf life than the other stuff. === Q. Why does organic milk have a longer shelf life, as signified by later expiration dates, than regular milk? A. Most organic milk undergoes a pasteurization process called UHT, for ultrahigh temperature, which involves heating it to more than 280 degrees Fahrenheit for two seconds. Most regular or fresh milk, Dr. Moraru said, is heated only to 161 degrees for a minimum of 15 seconds, a process called HTST — for high temperature, short time. The HTST process is designed to kill the disease-causing micro-organisms that are of concern in milk, for example the The UHT treatment, on the other hand, “is a sterilization process, which means that it kills practically all micro-organisms, both vegetative cells and spores,” Dr. Moraru said in an interview. As a result, the treated milk has a long shelf life, measured in months, even at room temperature. It is often labeled ultrapasteurized. Milk with either treatment lasts about five days after the container is opened. Most organic milk undergoes the hotter pasteurization process because the organic market is smaller, meaning the milk spends more time in the commercial distribution system and thus has to last longer, Dr. Moraru said.