I'm probably going to get flamed on this one but being in the business for 5 years and working with CN vendors that long you begin to see trends and these companies go from completely trustworthy and reliable to selling bad product with poor service overnight.
The business is very cutthroat and transient, especially with companies who are significantly diversified. When my team and I visited CN for the first time we met with a lab that was small but sterile with 4 chemists on staff. As we exited the building through a corridor we entered into a bicycle manufacturing shop that was owned by the same person who owned the lab. We returned to the same city 10 months later and the lab was gone and replaced with a Christmas tree factory. Everything was gone, hoods, mixers, granulators, tablet presses, crimp lines all gone. Trust NO one in this business. Test every batch yourself... it's a little costly but your safety is worth it.