|MadSci Network: General Biology|
Whole milk is what comes from the cow. If you leave it sit around for a while it will "cream" -- the fat globules will rise and form a cream layer, the milk below will be a partially "skim" milk. However, most consumers don't want to see this separation so the dairy industry "homogenizes" the milk -- by passing the milk through a high pressure system -- the fat droplets are broken into much smaller droplets and their surfaces become coated with protein and thus they are much more stable (though with enough time the cream would still rise -- but by then the milk would be spoiled). So when we normally buy milk it is "homogeneous" thanks to homogenization.
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