Sodium Propionate
Specification:FCC E281,HG2921-1999,Feed
Sodium propionate has the formula C₃H₅NaO₂,
It is the sodium salt of propionic acid.

Uses
[1]  As a food additive, it is listed as E number 281 in the Codex Alimentarius. sodium propionate is used as a preservative in a wide variety of products, including but not limited to bread, other baked goods, processed meat, whey, and other dairy products. 
[2]  In agriculture, it is used, amongst other things, to prevent milk fever in cows and as a feed supplement.
[3]  Propionates prevent microbes from producing the energy they need, like benzoates do. However, unlike benzoates, propionates do not require an acidic environment.
[4]  sodium propionate is used in bakery products as a mold inhibitor, typically at 0.1-0.4%.