I just heard a story on NPR about this company, ConsumerLab. They independently test nutritional supplements. A couple years ago this was a big deal and there was lots of talk about having the FDA oversee the nutritional supplement industry. Whenever I hear calls for the government to oversee new areas I cringe. I tend to think of the government, Federal, state or local, as being the least competent entity to accomplish any task. Think of time spent at the DMV or the "response" to Hurricane Katrina.
ConsumerLab makes their money by selling a subscription for the results of their studies. I don't know how successful they are, but I think people who use a lot of supplements will likely sign up. People, like me, who use very few supplements probably don't need this service. That's the beauty of it. Since my risk of consuming a contaminated substance is low I can spend that money on something else. Another nice thing is that, unlike the FDA, if ConsumerLab turns out to be incompetent at its job people will cancel their subscriptions and they will go out of business.