Quite right: they are poisonous when young. But fortunately, the toxic alkaloid also tastes absolutely horrible (very bitter), like a potato that has been exposed to sun and has turned green, so there is little risk of you poisoning yourself. I just tasted a green berry and had to spit it out. (Don't worry, I'm fine: it's not so poisonous that it would kill me to taste it, as foxglove and hemlock would be.)
