With 30 and 120 kDa chitosans, increase in chitosan concentration generally showed increased bac- terial growth inhibition in bread.The bread containing 30 or 120kDa chitosan at above 0.1% concentration showed 101 to 103 CFU/mL viable cells while the control bread containing no chitosan revealed 106 CFU/mL after storage for 8 d at room temperature.