In my opinion, a risk assessment is absolutely appropriate here and your action would depend solely on the result of this. If there is any chance that the poison came in direct contact with the food in a way that would introduce a risk that makes it unsafe, then yes - destruction is your only answer.
If, however, the hazardous material and your finished product each was separately packaged, there's no aerosolizing/air contaminant/off-odor issue, and they were otherwise kept separate except for being on the same trailer - a case could be made that the product is still safe. You might even find that one or two pallets are at risk, whereas the rest are not.
Make sure you have the best of your QA Team or management there when the trailer is opened, take lots of pictures, make sure the trucking company gives you documentation as to how and where the product was moved and/or handled (especially important if you have temperature controlled product). - i.e. don't base "the pallets were directly next to the poison will be destroyed" if you don't know for sure that the trucking company didn't move stuff around and other pallets would have been next to it.
This falls under a favorite quote of mine from a supplier: "Oh God, I love this. I love when people don't do what they're supposed to do. This gives me something to do now this whole afternoon, goodie!". Good luck!
Edited by Xoinks, 27 April 2020 - 08:20 PM.