The use of the atomic force microscope to visualise and measure wear of food contact surfaces

The atomic force microscope (AFM) promises to be a valuable tool for visualising and measuring the wear of food contact surfaces. Samples examined by the AFM require virtually no preparation, and the AFM gives roughness information down to the nanometer scale, enabling description of and discrimination between topographies of surfaces at levels below that normally specified as hygienic (R(a)0.8 mu-m). Stand-alone AFM enables direct and sequential measurement of wear of a surface over time. We have also use the AFM to examine less accessible food contact surfaces indirectly, using dental impression materials. Information gained from worn food contact surfaces sampled in situ has been used to reproduce typical worn stainless-steel surfaces in vitro, for subsequent realistic and rigorous fouling and cleanability testing, which in turn will provide valuable information on the effect of wear on the fouling and cleanability of surfaces on the nanometer scale.