Poppy seed = drugs?!

The company Ian works for started to do random drug tests. So Ian was randomly selected on Monday and was asked to undergo a drug test. He though ‘No worries.’. But he was told on Tuesday that he was tested positive on opiates… Of course he couldn’t explain why – he never took any drugs.
When he told me, I just laughed and said that must have been the poppy seed cake that you ate on Sunday night. At first he wouldn’t believe, but I started to search the internet and eventually convinced him. So he told the people at work about the cake and I think they also did another more precise drug test. Anyway, everything is fine now. But what a coincidence!! :)