2006 Volume 7 Issue 1 Pages 1-13
In food manufacturing processes, food products themselves adhere as soil residues on the surface of the equipment. Adherence of soil deposits causes contamination with microorganisms, which then brings the equipment into unsanitary conditions unless they are properly removed after the end of processing. Soil deposits in heat exchangers during processing markedly increase hydraulic and heat transfer resistances and thus removal of the soil deposits from the wall, i. e., cleaning of the equipment is conducted frequently. The author's first study on the rinsing of membranes fouled with milk protein that had been conducted in T. U. Mi nchen stimulated his further interest in the field of adhesion of soils on the solid surface and its cleaning of the fouled surface. In this review, the author summarizes his studies on the fundamental aspects of soil adhesion on the metal surface and cleaning, which were accomplished with his colleagues and students. In particular, the adsorption mechanism of proteins on the metal oxidized surface is investigated from the standpoint of the molecular level. The reason for the very strong interaction of proteinaceous soils to the metal surfaces is revealed, focusing to the interaction with the surface and conformational change in the adsorbed state. The author also summarizes the rinsing velocity and cleaning velocity during caustic and enzymatic cleanings in addition to radical cleanings that were developed by the author and his colleagues.
