The foam-drying method consists of

The foam-drying method consists of whipping a product to produce a stable foam to increase the surface area. The foam is then dried by warm air. Liquid products,such as egg white, fruit purees, and tomato paste, are dried in this manner. The method itself has very little lethal effect on microbial cells and spores. However, a concentration method before foaming, the pH of the products, and low Aw cause both lethal and reversible damages to microbial cells.