My parents just adopted 2 eastern box turtles, so I'm new at this. I know in the past turtles have been associated with salmonella. Are they still? What should we know about this?
box turtles are indangered so if you found them you should let them go. Yes they do have salmonela and you have to wash your hands after holding them.
Where did you get the box turtles?
It is absolutely NOT true that all turtles have salmonella. Any reptile may carry salmonella but a healthy one should NOT have it. If the box turtles came from a healthy population, they should be okay. You can have an exotics vet analyze the turtles' feces for salmonella. Out of curiosity, I had my sailfin lizard's water (full of feces) tested for salmonella a few years ago. It was negative for that but had fecal coliform and E. coli which are normal and ubiquitous. If the turtle tests positive, it can be cured of the salmonella with the right antibiotics.
Even if the turtles have salmonella, you will be safe as long as none of the said bacteria end up in your digestive system. This means washing up after handling the turtles and their things so you don't accidently put your hands to your mouth with turtle waste on them.
Box turtles are not legally endangered but they are certainly vastly decreasing in numbers. I agree with Tommy that if these turtles were recently wild caught, they should be released back where they were found. That doesn't sound like your case but I thought I'd mention it. My state allows one to keep one wild box turtle only; permits are required for more. Such limits in my state do also apply to captive-raised Eastern box turtles (I think) but that may not be the case in every state.
In New York you cant even have 1. In the 70s lots of people used to take turtles now there arent many left in New York.