Time Spanner wrote of the milk divide cartel in Auckland in days before you could buy milk in supermarkets.
As a kid on a dairy farm, I had to often get the billy of milk from the dairy. I was quite proud of my billy can swinging skills. I could swing the billy can in all directions including over my head and never a drop was spilt. Oh, I just remembered throwing a can of milk at my brother. He was very sticky. I am sure he deserved it.
In early farm days milk cans were used and simple dip of the billy into the can resulted in a lot of cream which would settle on top in the billy can. While I like a pavlova and cream on my tinned cling peaches, I hated the cream on top of the milk. Later came the modern refrigerated milk vat. My brother would dip the billy can into the milk vat and if the agitator hadn't been working for a while, yes, more greasy cream. I used to take the milk from the tap at the bottom of the vat and again if the agitator hadn't been working, not a drop of cream. So much nicer.
My grandparents for a time had their milk delivered in bottles, sealed with foil caps but in my memory, they walked to the local milk bar daily to buy bottles of milk.
A friend grew up in Calcutta, oh, Kolcata , whatever. The delivered milk was not to be trusted. It did not come in cartons from a factory in the sixties but in a container, probably a billy of sorts, and direct from the dairy.
My friend used to get their milk straight from the cow's udder. Well, sort of. A man and a cow would arrive and the cow would be milked in front of my friend's mother into a container she supplied. There was no chance of milk dilution to increase profits with filthy water that could cause them to become ill. (just occurred to me that the person milking could have water pump up his sleeve)
I would guess that milk dilution was a problem in both Australia and New Zealand before the heavy regulation of milk supply began and believe me, in the sixties and seventies is was very regulated.
We drink skim milk at home, mixed in jugs, but if we are having visitors we buy a carton of fresh milk. I hunt the fridge shelves at the shop for just plain milk. It is terribly difficult to find a carton of 'just milk'.
One thing about milk hasn't changed though, as I have noticed with Little Jo. Kids still end up with milk moustaches.