Antimicrobial Activity of Sodium Bicarbonate

Sodium bicarbonate (SB) inhibited the growth of bacteria and yeasts in agar media model systems under certain conditions. Escherichia coli, Lactobacillus plantarum, Staphylococcus aureus , and Pseudomonas aeruginosa aerobic plate counts were reduced 10,000‐fold by 0.12M (1% w/v) SB. Saccharomyces cerevisiae and Hansenula wingei were more sensitive; counts were reduced 100,000‐fold by 0.06M SB. Potassium bicarbonate was equally inhibitory, but equimolar sodium chloride had no effect, ruling out osmotic‐ and sodium‐mediated mechanisms of inhibition. The bicarbonate ion was identified as the probable cause of SB‐mediated inhibition although, in some cases, pH elevation played a significant role.