Before that, salmonella hadn't found its way up the fallopian tubes of chickens, and the window of opportunity for infection was fairly small. Probably killed any errant little buggers with wine and acidic foods, too.
Last I heard, in the USA, 1/20,000 eggs carries the bacteria. US Big Egg has managed to avoid paying the roughly $0.05/CHICKEN vaccination expense, and a chicken can lay just over 200 eggs.
I don't think they do. The EU has considerably different treatment for eggs than the US. For instance, they usually don't refrigerate them, and it's illegal for the producers to wash them. In the US, eggs are usually refrigerated, and the producers are required to wash them. The theory in the EU is that washing the eggs makes the shells more permeable to bacteria. Go figure.