A few years ago
Chinese baby milk makers got busted because they were adding melamine to their powder to make it look like it had more protein. End result: lots of hospitalised, injured and dead babies and zero confidence in Chinese-made foodstuffs.
Hong Kong got the brunt of it first. People were buying up all the supplies of baby milk and sending them through the mail. Or they'd go to Hong Kong, fill up a suitcase, and make tons of money selling them on the mainland.
When the Hong Kong government cracked down on it, Chinese vendors moved onto Korea, Taiwan, Japan, etc. Restrictions were quickly put in place there.
Australia's just the next link in this chain. It helps that Australian farmers feel they can make a profit this way instead of being forced by Coles/Woolworths/etc to accept pennies for milk. I'd be investing in this stuff if I were you guys.