You can specify the organization to receive your body, though some have prescreening.
Generally speaking, bodies donated to science don't end up being tested with ordinance. The consent waiver limits how the body can be used and is generally narrowed to medical research. One example where this didn't happen was here and the company founder was tried for fraud.
My suggestion for people is to find an organization that directly accepts donated bodies and go through their prescreening to bypass the body broker business.