In this article called “8 façons de t’intoxiquer à un barbecue” (which could be translated by “8 ways to poison yourself at a barbecue”), a Canadian skeptic talks about sprout seeds :
I would translate that by:
As for raw sprouts (bean sprouts, alfalfa, etc.), they are such 'nests' for bacteria that they should not be eaten by children or elderly people... I'm serious.
This guy, does not give any source for that (hum).
Is it true? Is there a scientific consensus about this?