Sodium Propionate E281 CAS：137-40-6

Sodium Propionate (CAS: 137-40-6) is a safe food additive primarily used as a mold inhibitor and preservative . According to the Chinese national standard GB 25549-2010, it is produced through the neutralization, purification, and drying of propionic acid with sodium hydroxide or sodium carbonate. It appears as white crystals, granules, or crystalline powder, with a faint characteristic odor (propionic acid smell). It is hygroscopic in moist air, readily soluble in water, and slightly soluble in ethanol . As an acid-type preservative, its antimicrobial effectiveness is higher in lower pH environments. It inhibits molds, aerobic spore-forming bacteria, and Gram-negative bacteria, and is particularly effective in preventing the production of aflatoxin. However, it does not affect yeast activity, making it suitable for yeast-leavened products like pastries . Functionally, it extends shelf life by preventing spoilage. It is widely used in pastries, bean products, cheese, soy sauce, and wet flour products. Per GB 2760, the maximum usage level in pastries is 2.5g/kg (as propionic acid); for waxberry canning processing, a 3%-5% solution is used with a maximum level of 50g/kg (as propionic acid), but must be thoroughly rinsed before processing . It is also used as a feed preservative and as a slime inhibitor in beer production .