Fluorescent lights in dairy cases create an oxidized off-flavour in milk that some experts call 'burnt.' The closer the milk container is to the light, and the longer it stays there, the greater the chance of an off-flavour, Marshall said in a statement.
While the oxidation has little effect on milk's nutritional value and is not related to bacteria, fluorescent light does inactivate riboflavin (vitamin B2) and ascorbic acid (vitamin C). Whole milk suffers the least because it has a high level of fat which blocks out the damaging wavelengths.
Milk in clear glass containers goes off-flavour quicker than milk in translucent plastic jugs, and opaque paper board cartons deter the problem altogether.
So when you buy milk, Marshall says, reach to the back of the dairy section.
"Get it from the dark, definitely don't get the front row," he noted.