Sodium sulfite also showed a decrease in furan concentration as seen with calcium and magnesium ions. However, the reduction rate of furan formation with added sodium sulfite was less than that with the two metal ions. At Day 10, there was a decrease in furan formation to 80% from 0.05 M sodium sulfite, 48% from 0.2 M sodium sulfite at Day 25, and about 16% at Day 30. Even though the activity of the reduction effect seemed less effective than the two metal ions, sodium sulfite could also be used as a furan-reduction tool like other food additives affected by decreasing furan in the soy sauce model system.