In the national standard, Caustic soda (or sodium hydroxide) is a “processing aid that can be used in the processing of various types of food, and the residual amount does not need to be limited”. In other words, the use of caustic soda in food is not “illegal” and there is no “excess” problem.
The use of caustic soda in food is to adjust the acidity. During processing, sometimes the pH needs to be lowered, and sometimes the pH needs to be raised. Sodium hydroxide is a strong base that efficiently raises the pH. In the final food, the “corrosiveness” of sodium hydroxide no longer exists.
The difference between food grade Sodium hydroxide and industrial grade Sodium hydroxide is the content of heavy metal impurities. Due to the prudent principle of food safety, it is necessary to use food grade to ensure maximum safety.