Someone just told me that Delta Society, I think–a national dog therapy training and licensing agency–is telling applicants that dogs on a raw meat diet can exude through their skin something or other that might endanger patients with severely compromised immune systems.
Huh?
I think raw meat diets, or raw meat with vegetable supplement, are stupid for a number of reasons, but that’s not the question here.
I’ve heard that Salmonella can be shed in the feces of carnivores on raw meat diets.
ETA: Cite
Sorry for going off-topic, but I LOVE the name of the diet mentioned in your cite. The BARF diet??!!
Many dogs love to eat barf. 
Salmonella can be shed in dogs’ feces on any diet, but is more likely when the dog eats a raw diet.
Not that people in nursing homes or wherever are likely to encounter the therapy dog’s poop. But considering how dogs clean themselves…
Would some of the reason have anything to do with antibiotic use with cattle?
How does that relate? Do you mean that dogs who eat antibiotic-infused raw beef somehow compromise the health of immune-supressed people?
Not the dogs, the feces. If the antibiotic-resistant bacteria (from animal food products that are treated with antibiotics) are vectored to the patient, this would be another area of concern for immune-suppressed folks. And would be another reason why dogs are not allowed to hang around.
(Of course, this contingent on the dog food coming from “industrially raised” food sources (a term I just made up. I no nothing about the source of dog food, other than at one time, wild mustangs were part of Fido’s diet in the late 60’s).
Admittedly, this is only speculation, and my guess is the chances are pretty remote, but figured that it might be on someone’s radar.
I thought actually that raw-food givers never gave raw chicken. What assholes.
Well, I am one of those whackos who feeds a (primarily) raw diet to my dogs and have done so since 1999. 
Chicken is definitely a regular on the menu. Beef is not, mainly because it’s quite expensive when you have about 250 lbs (combined) of dog to feed.
Also one of my current dogs, and a past dog, are/were certified therapy dogs. Neither with Delta, though. The two organizations I have worked with (Therapy Dogs International and Mid-Michigan Therapy Dogs) have no restrictions regarding diet.