Milk, long an emblem of wholesomeness and virtue, has never been more controversial. Most American adults grew up believing they should drink three glasses a day, but recent research has implicated dairy in a host of health problems, from breakouts and indigestion to heart disease and cancer. Environmentalists worry about dairy farms’ carbon emissions. Animal lovers worry about the cows’ quality of life.

At the same time, milk skeptics have never had more alternatives. If you want a variant of traditional cow milk, you can choose from lactose-free, slaughter-free, organic, skimmed, semi-skimmed, pasteurized or raw. Goats and sheep produce milk, too, which some claim is healthier. According to Josh Harkinson of Mother Jones, only certain types of cows—Asian and African ones—make milk suitable for human digestion. Milk-like products made from almond, soy, rice, oat, hemp, coconut, or cashew all have their proponents and detractors.

Yet there’s one kind of milk that’s almost never mentioned in the United States—even though it’s the most popular type in many parts of Europe and South America, has a smaller environmental impact, a longer shelf life, and a similar taste and nutritional profile to regular cow’s milk. UHT milk—named after the “ultra-high temperature” process by which it’s treated, and sometimes called shelf-stable or aseptic milk—is briefly heated to about 275 degrees Fahrenheit and packed into sterile containers in which it can stay fresh, without refrigeration, for as long as six months. Most milk sold in the U.S. is pasteurized: It’s typically heated to about 160 degrees for a second to kill off bacteria and extend its shelf life, though it still requires refrigeration and expires within about a week. Pasteurization was invented in the 1930s; ultra-high treatment came along about 30 years later.

According to The Times of London, in 2007, UHT milk accounted for 96.7 percent of total milk consumption in Belgium, 95.5 percent of the milk drunk in France, and 95.7 percent of the milk consumed in Spain. Its popularity varies widely across Europe; it accounts for just one percent of milk sales in Greece, 2.4 percent in Finland, and 8.4 percent in Britain. There’s a growing market for UHT in Asia; Bruce Krupke, Executive Vice President at Northeast Dairy Foods Association, estimated that 70 percent of the milk sold in China is UHT.

American visitors to European or South American countries are often dismayed at the difficulty of finding fresh milk. “The French appreciate fresh vegetables, bread etc., but apparently not milk? How can that be?” asked one commenter on the travel site Eupedia. “There's something that has confused and bothered me ever since I got here,” confessed a blogger who’d moved to Belgium. “I thought it odd that all the milk for sale in the grocery stores was sold unrefrigerated”—even though Belgium is “full of dairy cows.”