We were told this as kids. In the '50s. Ever heard of such a thing?
Peace,
mangeorgre
Never heard it, but it could spread bacteria around throughout the bulk of the milk. Doesn’t the same thing happen once meat is ground?
WAG: Milk is an emulsion of fat suspended in an aqueous phase. Shaking some emulsions can cause the fat/hydrophobic parts to come out of suspension. I’ve never seen it with milk, but I do recall seeing it with a pharmaceutical product (and what a disgusting thing that was to look at!). I don’t know if it’s possible to separate milk this way.
If you shake it using a circular motion i.e. a centrifuge, then butterfat separates from the whey. But skim milk fraction is sweeter that the full cream milk as the % sugars is higher.
Shaking the milk into a froth will increase the surface area. That would cause the milk to sour quicker, temperature and exposure permitting.
Wait…I thought back then a lot of milk HAD to be shaken, because it wasn’t homogenized and the fat would come out of suspension, so if you wanted actual whole milk, and not skim milk with cream on top, you’d have to shake it.
Unprocessed whole milk if shaken enough the solids will seperate. My brother use to have a quart jar of whole milk with his lunch years ago. Every now and then the guys he was working with would get to his lunch and shake the milk. He would go to lunch and have a jar with butter milk and butter.
Oh I remember that too. I used to get into big trouble for sipping the cream off the top. Good boys got to lick the little paper cap. We got milk from the milkman in glass bottles.