Preservation of high‐moisture dried prunes with sodium benzoate instead of potassium sorbate

Abstract The relative efficacy of sodium benzoate and potassium sorbate as preservatives for high‐moisture dried prunes was determined using prunes with moisture contents between 31 and 38%. As the moisture content of the prunes increased, the level of preservative required increased. Higher concentrations of sodium benzoate than potassium sorbate were required to achieve equal protection of prunes from spoilage. The relative efficacy of these preservatives varies with the type of microbial spoilage. While sodium benzoate generally appeared to be about equally effective against the yeast and moulds used, potassium sorbate was more effective against the mould than against the yeasts. It appeared that it would take 40 to 90% more sodium benzoate than potassium sorbate to preserve high‐moisture dried prunes from both types of spoilage. On the basis of the present commercial levels of potassium sorbate, it should be possible to preserve commercially produced high‐moisture dried prunes using sodium benzoate without exceeding the U.S. legal limit of 0.1%.