While what the Chinese have done is a travesty, the USA has some serious questions to answer on dairy health as well. I'm sure to be blasted for this but the US is the only developed country in the world to not have banned the genetically engineered and artificial growth hormone rBGH or "recombinant bovine growth hormone" from it's dairy products. Australia, New Zealand, Japan, and every country in the European Union have banned the use of this in dairy production.
When using something as concentrated and isolated as protein powder I wouldn't want to be comsuming copious amounts of this.
As TC mentioned previously, Biotest were sourcing protein from NZ or Australia. I hope they still are, or at least a rBGH free dairy from the US.
If you are worried do a google search in recombinant bovine growth hormone.