Intermediate Moisture Foods

Abstract

Foods that can be preserved in a simple way at ambient temperatures (by restricting water mobility) and that are moist enough to be consumed without rehydration traditionally have come to be known as intermediate moisture (IM) foods. Their shelf stability at ambient temperatures is attributed mainly to adjustment and control of water activity. Moisture content of IM foods varies between dried foods with levels of less than 7%, which can be stored at room temperatures, and fresh foods with levels of 60–80%, and above which need to be preserved by an additional method and still may have a limited shelf life, albeit higher than that of the fresh counterpart. Usual ranges of water levels are between 10 and 50% and water activities (aw) vary from 0.65 to 0.90. Therefore, IM foods can be classified as partially dehydrated foods with suitable concentrations of dissolved solids to inhibit the growth of bacteria, molds, and yeasts and to control undesirable enzymatic activity. Fruits, vegetables, fish, and meats are processed successfully processed into IM-range products.