Scared about getting Samonella from sister's tortoise?

Well, my sister got her Sulcata tortoise from the tortoise shack, where they raise and breed turtles in captivity. I heard that turtles carry it more than tortoises, but im still concerned. I'm thirteen years old, and my immune system is pretty decent. I mean, i never stick the thing in my mouth, and i always wash my hands after i hold or touch it, but im worried about touching a surface i have touched after touching the tortoise and getting it.... is it rare to get it from a tortoise?