. Furthermore, acidic protease activities in the fermented jerky (61.9 U/g), and the remaining fermented medium (5.24 U/mL) were both higher than the neutral protease activities (43.1 U/g and 4.77 U/mL, respectively). This was because the optimal fermentation condition for Lactobacillus bulgaricus was acidic (pH ¼ 6.5), which also meant that it was appropriate for Lactobacillus bulgaricus to produce fermented jerky under acidic conditions.