Ammonium Propionate — Frequently Asked Questions

Because it is deliquescent. Unlike the calcium and sodium salts it absorbs enough atmospheric moisture to dissolve in it, so a free-flowing powder cannot be maintained in normal storage. It is therefore supplied as an aqueous solution, typically around 50 percent, or absorbed onto a solid carrier for dry dosing.

The solution is sprayed onto the grain as it passes into store, typically on an auger or conveyor, at a rate calculated from the grain moisture content and the intended storage period. Wetter grain and longer storage require higher application. Even coverage matters, since untreated pockets will heat and mould regardless of the average dose.

Corrosivity. Neat propionic acid attacks augers, bins and handling equipment and is hazardous to the operator applying it. Ammonium propionate is buffered and far less corrosive while delivering the same antifungal propionate chemistry, which makes it practical to apply on farm equipment that would not survive repeated acid treatment.

In ruminants, yes. Rumen microbes can convert non-protein nitrogen into microbial protein, so the ammonium has feeding value as well as the preservative doing its job. In monogastric animals, pigs and poultry, that conversion does not occur, so the nitrogen has no nutritional value and only the preservative effect applies.