I got suck in US customs once over a pork sandwich. My Aunt had made me a sandwich with last night's dinner leftovers and mayo (that's what is done in Denmark). I didn't finish it all and had forgot about it in my bag. When I landed in New York, I realized that there was a lot of worry about Hoof and Mouth disease.
They wouldn't let me throw the sandwich out in customs, but they refused to allow me to enter the states with it on me. I was refusing to eat it because it had mayo that was shiny from not having been refridgerated and I was scared of food poisoning in the states where I had no medical coverage.
I was several hours arguing with them and my parents who had driven from Canada to pick me up had no information about what was happening. My Mom was FREAKING out. I was finally allowed to leave with the instructions that I had to hold on to the sandwich until I got to Canada and dispose of it there.
The whole thing was pretty funny since there were no reported cases of Hoof and Mouth disease in Denmark at the time and it was definitely Danish meat.