According to that link, the laws are mostly recent, passed in the 2010s rather than 1990s, e.g. 2014 for Idaho's and 2012 for Missouri's. And I don't see anywhere there that they've all been struck down. Only one is mentioned as having been struck down, Idaho's, and from what I can find that's still being litigated, currently being heard by an appeals court [1].

[1] http://www.foodsafetynews.com/2015/12/idaho-appeals-federal-...