Elimination of Escherichia coli from Oysters using Sodium Bicarbonate

Abstract

Sodium bicarbonate is a disinfectant that can be used in food processing because it is safe for humans and is cost effective. In this study, sodium bicarbonate was used to eliminate E. coli from oysters (Crassostrea belcheri). The experiments were divided into 3 trials; in vitro disinfection of E. coli using sodium bicarbonate and the toxicity of sodium bicarbonate in oysters were determined in the first and second trials, and the effectiveness of sodium bicarbonate in eliminating E. coli in naturally contaminated oysters was performed in the final trial. From the in vitro study, it was found that sodium bicarbonate at 10 and 100 mM could inhibit E. coli; however, the high dose of 100 mM is not suitable to use on oysters, since the 50 % lethal concentration of sodium bicarbonate for oysters was 63 mM. An application of sodium bicarbonate to eliminate E. coli in naturally contaminated oysters at 10 mM for 1 h could decrease the E. coli to 96 MPN/100 g, lower than the standard level (230 MPN/100 g) after depuration. These results suggest that sodium bicarbonate could be potentially used to eliminate E. coli contamination in oysters.

Keywords

• Sodium bicarbonate
• elimination
• oyster
• E. coli