To their credit, Costco tests and inspects their meat themselves. A shocking revelation by Costco's food safety director is, “Tyson will not supply us. They don’t want us to test." Why? Because if there is a problem, they do not want the scrutiny a report to the government would bring.
The number of significant health problems seems to be somewhat small, but there potential of huge problems. I am guessing after a few of the multi-million lawsuits go through the courts, some of these practices will change...until then down with American (ground) Beef.