BEIJING (AP) — China learned hard lessons from a contaminated milk scandal that left six babies dead four years ago but its dairy industry is still plagued by quality lapses, from toxic mold in milk to mercury in baby formula.

Experts say the new scandals have a silver lining: they show the industry’s new transparency. But the persistent problems also underscore that milk is a new addition to the Chinese diet and it will be a long time before it’s truly safe.