Feeling the effect isn't the issue. Testing positive on a sensitive test is. There is a difference. There are false positives. Proving it is hard. Most companies have a zero tolerance. One positive, false or otherwise, and you are history.Actually, that kind of makes sense, since the seeds we eat come from opium poppies, which is also used to make opium. But the amount of opiates in the seeds themselves is minimal, so I think you would have to eat a ton of seeds to actually feel any effect.
I worked a job where I was "randomly" selected for 14 of the 18 months I worked there. Yep, I passed every test they administered. Took my boss asking if this was really random before it stopped. I wanted to know who thought I was doing drugs and what drugs they thought could improve me. Never got answers.