The removal of β-lactoglobulin from stainless steel surfaces at high and low temperature as influenced by the type and concentration of cleaning agent

In the food industry, severe fouling of equipment surfaces is common and frequent cleaning is necessary. The aim of this work was to contribute to an understanding of the cleaning process. The adsorption of beta-lactoglobulin (beta-LG) onto stainless steel surfaces and its removal by detergent were followed at 24 and 82C using in situ ellipsometry. Soil removal using different concentrations of sodium hydroxide was studied. Furthermore, NaOH was combined with the anionic surfactant sodium dodecyl sulphate (SDS). Increasing the NaOH concentration resulted in an enhanced cleaning rate and better cleanability. When the concentration was increased to 0.8 mg/mL, the cleaning process could no longer be monitored by ellipsometry. Combining SDS with NaOH resulted in improved cleaning compared to if using the individual components. Adsorption and removal of beta-LG at high temperature led in all cases to decreased cleanability compared to the results obtained at room temperature.