Ultrasound is well suited to the study of food materials because of the possibility of noninvasive and safe implementation which is ideal for hygienic application. New advances in the understanding of the interaction between the soft solids which comprise many foods and ultrasound mean that new data and new insights into foods have been gained using ultrasound measurement techniques. Studies of complex food materials have challenged theories of ultrasound propagation, resulting in significant theoretical developments of general importance. This review covers the use of low power ultrasound to study food materials. Both pulse echo and continuous wave interferometry are covered and the theory of ultrasound scattering in soft heterogeneous media discussed. Foods to which the ultrasound technique has been applied range from eggs through margarine to chocolate.