Surface Roughness and Cleanability: Evaluating the Impact of Magnetic Abrasive Finishing on Dairy Equipment

Abstract

Stainless steel tubes and pipes are vital in dairy processing but require frequent cleaning, leading to notable energy consumption and environmental impact. This study delves into the cleanability of wet milk deposits at temperatures of 40°C and 60°C on an exceptionally smooth internal surface achieved through magnetic abrasive finishing (MAF) with a surface roughness of 0.01 μm R_a. We compare this surface with non-MAF tubes having surface roughness values of 0.37 and 3.7 μm R_a. To assess cleaning effectiveness, the study measured milk and protein residue removal after deposition and cleaning processes, employing a cleaning solution flow pattern at Reynolds numbers (Re) of 659–1318. Results indicate that smoother surfaces, particularly those with roughness values of 0.01 and 0.37 μm R_a, significantly enhance cleanability at 40°C. This leads to reductions (p < 0.05) of 34.5% and 22.6% for milk deposits and 27.9% and 22.7% for protein deposits, respectively, compared to tube surfaces with a roughness level of 3.7 μm R_a. These findings underscore the potential of highly smooth surfaces to improve cleanability below protein denaturation temperatures. Furthermore, the MAF tube with a roughness of 0.01 μm R_a exhibited nonsignificant reductions of 15.4% and 6.7% compared to the 0.37 μm R_a surface. The smoothing effect on the cleanability of milk and protein deposits was enhanced compared with the higher temperature condition. By addressing the challenges of routine cleaning, the study highlights MAF as a technology that optimizes surface quality in dairy processing equipment, addressing environmental and energy-related concerns.