I think the chances of him transmitting herpes to visitors in this way is low but I am certain that the department of health in your state/city would be horrified at this practice for other bacteria or viruses that he could transmit to others.
As an employee, you are in a very awkward position to deal with this very difficult situation. If you do not feel comfortable confronting him directly, which you may well, I would consider reporting this to the health department, anonymously if you need to. Are there other employees who observe this as well?
The dilution factor makes herpes really unlikely but again, other things could more easily be transmitted to others. Plus the YUCK factor is very high, don't you agree?
Dear Mrs. Warren,
thanks a lot for a quick reply. You are right the situation is very difficult. And the yuck factor.... However I don´t feel comfortable to report it, for me it´s like a betrayal. Yes, others saw it as well. In fact we have a rather high personnel rotation, so a lot of people must have seen it.) Even if I say something to him directly, there is no reason why my opinion should weight more than the opinion of this person who told him about it once in the past.
There is one thing I don´t understand though. You say the infection is very unlikely because of dilution. So it leads to a conclusion that the infection is not highly transmissible. Then how come so many people have it?
Lots of people have it because adults kiss kids with cold sores on their mouths and people with cold sore infections, whether there are symptoms or not, give oral sex to other people and transmit this to their genitals. There are behaviors that are likely to transmit herpes and there are behaviors that are unlikely to transmit herpes. Mouth to mouth and mouth to genital contact is likely to transmit - transmitting through inanimate objects or food is unlikely to transmit herpes.