Bitting out of nowhere

by Georgios
(Limassol, Cyprus)

I have a 7 year old jrt. My little devil out of nowhere will bite anyone except me(owner). This happens rarely. Most of the time he is the loving dog that everyone dreams off having but there is that moment, that moment you get caught on surprise by him and you get bitten. How can i make him stop biting people? We love him SO MUCH and we want to help him to stop this behavior. Even after his bite he realizes it and he shows that he regret about it and also he is aware of what he did was wrong :(

Please help us