OBoile

I would never have given a 2nd thought to food.
Having said that, I wasn't very good and tests didn't happen all that often (they were quite expensive and there isn't much money in PL). I knew I wasn't trying to cheat, and since I was maybe cat 3 level, I wasn't going to obsess over stuff. I did check when I got some meds from my doctor though.
Mrs. OBoile got tested after winning her first national championship. Neither of us had paid attention to what she ate previously. She passed.
That being said, a surprising number of people did test positive for what was essentially a hobby (no one is making a living doing this). This is particularly depressing wrt human nature when you factor in that there was another league which was untested (i.e. drug use was welcome). This was quite eye-opening for me. I like to think that people are fundamentally honest, but that really isn't the case for a very large portion of the population.
To the best of my knowledge, no one ever got caught based on the food they ate.
Right as I was getting out of the sport, they introduced a new program (for all Canadian sports that follow WADA I believe) that upon joining, you had to take a course on the rules wrt anti-doping so that you couldn't claim ignorance in cases like this. Unless the rules have changed in the last couple of years, it's quite clear that athletes are responsible for what is in their body, even if it is by accident. As asgelle said, the fact that the sentence wasn't reduced indicates the CAS didn't fell that was the case here.

I'm sure there are hundreds, if not thousands of tested athletes in the USA who eat pork. If this was something that could easily happen, you'd likely hear about "false" positives more often.