Recently in Australia, a news outlet featured a dairy industry whistleblower exposing the controversial use of permeate – previously considered a waste product of milk processing, but now routinely being used as an additive (in milk) to save money.
From Today Tonight:
What the major companies are doing is that after milking, solids that are separated out, pasteurized, homogenized, reduced, and refined are then mixed back. The big secret that's kept from the public is they also mix in a lot of the cheap, filler additive consisting mainly of lactose. The left-overs of milk production called permeate.
Normal milk from the farmer is around 50 cents a litre, while permeate's about fifteen cents - 35 cents a litre cheaper. A large milk processing company produces around 1.64 million litres of milk a day, 600 million litres a year. Substituting twelve per cent of that milk with permeate, saves $69,000 a day, or $25 million a year.