A micromanipulation technique has been used to measure directly the adhesive strength of whey protein deposits on a stainless-steel surface. The principle of this technique is to use a T-shaped probe to pull fouling deposits away from the surface to which they are attached, and to measure the force imposed on the probe simultaneously. The apparent adhesive strength between the fouling deposits and the substrate was measured as the work required to remove the deposits per unit area from the surface. Measured values of the apparent cohesive/adhesive strength were between 0 and 10 J m(-2), which was a function of temperature, cleaning agent concentration and exposure time. The adhesive strength of whey protein deposits was greater than the cohesive strength at room temperature. The results can be compared with larger-scale cleaning processes, and potentially used to design new cleaning processes and operating protocols. (c) 2005 Elsevier Ltd. All rights reserved.