Long story short. We send it, we seal it. They take it across the border - NAFTA #, excise #, commercial invoice, bill of lading. The border gives them a passcode. They arrive in TN and cannot be opened until the USDA?? (mind blank but I'm certain it's them) arrives and THEY inspect the cargo on site.
I expect numerous of the goods that arrive in port are also inspected at their final destination point.
Saw a really good show about port security in the Discovery channel before Xmas. They may have info on it on their website.
Sheri