While heating of meat products containing nitrites at high temperatures increases the formations of N-nitroso compounds, does the same happen during fermentation e.g. during dry fermentation of sausages (salami)?
No N-nitroso compounds are formed during meat fermentation. However, during prolonged, poorly controlled meat (sausage) fermentation without appropriate starters, some biogenic amines may be formed which may react with nitrite if you fry such products (which you should not do, anyway).