Just to dispell a myth ...
You cannot vaccinate hens against salmonella:
- You cannot build up permanent resistance against salmonella (that is why you can contract repeatable salmonella food poisoning)
- It would be totally uneconomic to vaccinate each hen
In my view it is plain misleading to say these hens are vaccinated. What happens is that they are in huge sheds and get daily antibiotics through their drinking water system. In order to dose the antibiotics correctly you need a minimum of 1000 hens using the water system.
So if you eat these eggs you are right potential salmonella bacterium will have been killed but at the same time you get antibiotics as well.