Egg cant have salmonella or other bacteria inside; if all shell layers are intact, they don’t become addled, just dry out in a few months.Salmonella inoculums, however, can be on the sell surface, and get into the liquid when you break the egg. Nowdays eggs are cleaned carefully after collecting, but you can wash them yourself one more time to completely avoid this problem.
Lets check it in 50 years, and see if there is any gas at all…