这篇2019年的文章说美国有60～80%猪肉使用了廋肉精，而且商标上没有标明是看不出的

买肉要买有AGA标签的。我家的肉大都在Costco买，那儿的肉好像没有这个标签。

Pork producers aren’t required to tell you they use ractopamine, so don’t bother looking for it on the label. To avoid it, buy from a trusted local farmer, or look for the American Grassfed Association (AGA) logo—AGA-certified meat prohibits the use of ractopamine.

https://www.organicconsumers.org/blog/controversial-drug-ractopamine-back-news-and-still-your-food