Microbial stability as affected by water activity.

Abstract

The oldest method of preserving foods against microbiological spoilage is probably by drying. Inhabitants of ancient Egypt preserved grains by drying and storing them in granaries. No doubt, a combination of salting and smoking meat and fish, and drying fruits and vegetables was practiced long before recorded history. Not until recent decades have food microbiologists explored the behavior of microorganisms at a molecular level to determine the reasons why growth and metabolic activities of bacteria, molds, and yeasts are retarded and eventually inhibited as the water activity (a w ) of foods is decreased.