i have had experience with this myself, and at 7 months old, it will take
longer, but is definately curable.
 
i got my ferret at 14 weeks old from a breeder, and the first thing he
did was draw blood on me.  it was awful, i couldn't touch him, he saw my
hand as a chew toy or food, but not as something to pet him.  i was
really thinking i had made a BIG mistake.
 
i tried the bitter apple, which he quickly learned didn't get worse after
the first crunch, then scruffing, which only made him see it as a battle
when i let him go...i asked advice and tried everything that made sense,
but only one thing worked for us.  i had a little (3 inch) stuffed animal
toy, and when he bit me, i yelled no loud, and offered my hand again, if
he didn't draw blood, we played, if he did, i yelled no again, and when
he opened his mouth to bite, i stuck the toy in there and walked away.
you'd be surprised how much they want you, and when you leave it really
hurts them, they have a short attention span, so i would do this every 15
minutes he was awake, and honestly, he hasn't bitten me or a stranger, in
2 years.  it will take time and patience, but he just needs to learn his
limits.
 
i had people tell me to thump him on the nose or to run him to the
kitchen and put him under cold water...please don't do this.  you are the
adult, he is a baby, and doing anything to hurt him or scare him will
only make him distrust you, but it will never cure him of biting.  just
be patient, and consistent, and you'll get there.
 
p.s.  to the poster who said it might be because of his male hormones...
i know that is the common belief, but i can tell you from first hand
experience, my non-neutered breeding male is the least aggressive of all
6 i own.  he's just a big lump of love, even during breeding season.
it's just like a dog, it depends how they're raised alot more than if
they're neutered or not.  he will go after other male ferrets, but never
people.  i have a young female that thinks she's a silent killer, she'll
stalk you and then jump you, but that's not mean, either, just excess
energy!
[Posted in FML issue 4677]