You can't get Hepatitis B from saliva. Hepatitis B is blood borned virus and STD.
In the scenario you describe no. But hep b can be passed through saliva although the main methods are blood and sexual bodlily fluids
the chance is low and contagios rare but the virus is present in the saliva so you must get the vaccine to be 100% sure.
the most contagious are people in the immune tollerant state who have from millions to billions of hbv in the blood.
hbv is at least 100% times more contagious than hiv and the virus can live 7 days on objects and surfaces
although very rare and difficult to get it from a spit on a meal i would make vaccine anyway
for example i have problems with my gums and when i eat an apple i leave blood on it, same thing when i wash my teeth i lose a lot of blood, so you find blood in my saliva and virus too, i guess even a kiss from me can be contagious, fortunately in my country vaccine is mandatory at birth from the '80 so i cannot spread hbv anywhere