When you think of the dairy aisle of a grocery store, a chilled, brightly lit space is what most likely comes to mind. But it turns out that the fluorescent bulbs that let you locate your mozzarella and your yogurt aren’t necessarily so helpful when it comes to preserving milk. According to a study in The Journal of Dairy Science by Virginia Tech scientists, fluorescent lighting drastically changes the flavor profile of milk when the milk has been exposed long enough—sometimes for as short as two hours—in a translucent plastic jug. In blind taste tests, volunteers determined that milk that was exposed to fluorescent lighting tasted “stale,” “painty” and like “cardboard.”
Maybe you like your milk “painty,” but on the whole, it is not an attractive description. What accounts for the flavor change? Oxidation of nutrients, the study notes, including riboflavin, which gives milk its sweet, smooth taste. Have no fear, though—you won’t have to switch to almond or soy milk yet if you don’t want to. There are some solutions. The obvious one, of course, is buying milk in light-proof containers, so the milk won’t have been oxidized by the time it reaches your lips. Susan Duncan, a professor of food science and technology who was part of the research team that conducted the milk study, tells The Wall Street Journal that you should also look for containers of milk low on shelves or tucked away in dark corners so they haven’t been tainted.
A second, more involved solution is to use LED lights in grocery stores, which is what the study suggests as a practical workaround. The study found that, when sampled, milk that had been exposed to LED lighting was more favorably rated than milk that had been exposed to fluorescent lighting.
All in all, I think these findings are pretty disturbing, but I’ve never actually heard anyone complain about the flavor of milk, so maybe it's not that big a deal. Kind of like how cavendish bananas—the ones we eat today that are supposedly going extinct—apparently suck, but we can’t really know for sure because we’ve never experienced anything else.