This study aims to improve knowledge on fermented beef and fallow deer sausages and the effect of nitrite elimination and the addition of freeze dried acid whey on the fatty acid profile and volatile compounds. Three different formulations within each of the two product groups, made of beef and fallow deer meat, respectively, were prepared: control sample with sodium nitrite, sample without nitrite, and sample without nitrite and with the addition of freeze-dried acid whey powder (0.7%). After production, the sausages were subjected to analysis including proximate chemical composition, pH and water activity, Thiobarbituric Acid Reactive Substance (TBARS), fatty acid profile, and volatile compound determination. The fermented sausages were characterized by an average pH and water activity in the range of 5.23–5.79 and 0.910–0.918, respectively. Fallow deer sausages were characterized by a higher content of saturated and polyunsaturated fatty acids in comparison to beef sausages. The elimination of nitrite did not significantly affect the amount of volatile compounds in fermented sausages. However, the effect of the freeze-dried acid whey powder addition on the amount of some volatile compounds in uncured sausages was observed, in particular, that derived from bacterial metabolism.