I ate some steamed vegetables in a Chinese restaurant - thinking I was making a healthy choice given the circumstances - but when I was eating them I noticed they were all covered in tiny, black flakes.

I've googled what they might have been and have come up with the black patina layer that covers a well seasoned wok. Somehow they must have flaked off into the food. Is this normal???

I know the chef used an iron wok... thing is... are these flakes harmless or have I just eated a whole bunch of horrendous charcoal/iron/patina???

Anyone know?
Thanks.