Fermentation of Mutton Sausages with L. fermentum

Fresh mutton hindleg meat and tail fat were obtained from a local commercial processor (Hohhot, China), and sausages were made with modifications to the method previously described^{47 (link)}. The sausage's ingredients were as follows: mutton hindleg meat (70%), mutton tail fat (30%), salt (2.5%), glucose (0.5%), sugar (1%), NaNO₂ (0.01%), ascorbic acid (0.05%), pepper powder (0.2%), ginger powder (0.2%), spice powder (0.1%), corn starch (1%), and lactalbumin powder (0.5%). The ingredients were thoroughly mixed and filled into pig casings. The sausage diameter was approximately 3 cm, and length was approximately 20 cm. Control was fermented sausage without starter culture and the treatment was fermented sausage inoculated with L.fermentum 332 (the concentration of the starter culture was 4%, 10⁶ CFU/g). For 24 h, fermentation was carried out at 30 °C and 95% relative humidity (day 1). This was known as the fermentation period. For four days, the sausages were placed in a 15 °C and 75–85% relative humidity environment (day 5). This stage was regarded as the drying period. Then, the sausages were transferred to an environment of 10 °C and 65% relative humidity for 6 days (day 11). This stage was regarded as the maturation period. After preparation, the samples were packed and stored at − 20 °C until further analyses. The sausages in both groups were sampled at various fermentation times (day 1, 5, and 11) to determine AI-2 activity, LAB viable count, physicochemical characteristics, and volatile flavor components.