Also remember that most things can carry salmonella, Cats carry more diseases you can get then any reptile. Same with dogs, But you dont see people saying dont keep or pet dogs because you can get Salmonella, or Fleas, or any of that stuff. Most Salmonella cases are from food, Usually something like eggs or peanut butter.

Anyway, Theres a few simple rules to follow to not get salmonella.
1. wash your hands
2. Keep the tank clean
3. If your sick, might be a day to let the snake be and not handle him, for your and his sake.
4. Dont lick your snake
5. Dont kiss your snake
6. Dont touch his feces with your hands, If you do, wash your hands thoroughly, Just use a paper towel or toilet paper to pick up after him.

*A few of the above items on the list are sarcastic...*

But anyway, the public link of Salmonella to Reptiles came about with Baby turtles after Teenage Mutain Ninja Turtles Came out, A bunch of people got turtles as pets, hatchlings/juvies usually, Along with a spike in Iguanas bought after Jurassic park. Little kids would put these in there mouths like todlers do with everything, and of course direct oral contact is one of the main catalysts of disease transmission.

But also there is a public link between reptiles and salmonella even though its very very rare, and on a person-animal ratio, most other pets give more diseases more often then reptiles. People just dont like reptiles as much as the furry counterparts, and salmonella has been made the public spokesdisease for anti-reptile crusades.

In short, Its public concerns that are realitivly unfounded, Not a huge deal, but washing your hand after touching or holding any animal, furry or scaley, wild, domestic or exotic is a good practice to have, and definitally washing your hands with something like Purell, will take that question of worry out of your and your moms mind hopefully.