Eggs start to deteriorate from the time they are laid. As to salmonella, this will have to be addressed on the producer level. Foodservice operations have a habit to break eggs in bulk, cracking them together for omlettes or bulk scrambled eggs and then storing them unrefrigerated. Very dangerous as related to salmonella. There is a lot of useful info here.
Eggs start to deteriorate from the time they are laid.
Very dangerous as related to salmonella.