Like most animals, if they feel threatened or scared, they can and will bite. However, I think it depends on several factors. some can be very sweet and good tempered, like our frog, Bubba. wemve had her nearly a year now and she has never bitten either of us. worst that happened was a misfire where her sticky tongue got on our fingers, but she never bit down. she knows the difference between fingers and worms and shems a good girl.
Some people seem to have a lot of trouble with biting, but in my experience, they are usually the same people who are poking the frog in the face to try to get it to do something on camera. Treat your frog with love and respect and it will probably treat you good too.