Jerry shows classic germophobia In the episode when his girlfriend brushed her teeth with the toothbrush that he had accidentally dropped in the toilet. When he told her, she got so mad that she put something of Jerry's into the toilet, but wouldn't tell him what, so he started throwing stuff away.
I thought it was odd that Jerry was not included in the later episode when the woman from Elaine's office was a germophobic about Elaine. Seems Jerry should have been part of the germoholic/phobic gang, especially at the end when they were eating the salad Kramer had prepared in the shower.