In our case I have a just opened 30 pound bag that appears to make our 5 dogs ill.

yet beneful refuses to test it for toxins,

toxicity could come from something in the bags material, some idiot poisoning in the supply chain etc.

they should get as many samples as possible, compare production locations, ship and manufacturer dates to see where the source might be from.

instead they refuse to do anything but a visual inspection...

remember the tylenol scare. idiots were adding poision to the bottles. perhaps beneful doesnt want more expensive packaging?

our dogs always had beneful, but have a varied tasty food.

liver, fresh boneless chicken breasts etc