Elucidating the cleaning of complex food soil layers by in-situ measurements

The mechanisms involved in cleaning a heterogeneous, multicomponent baked food soil off stainless steel surfaces in aqueous solutions were investigated using novel tools to quantify changes in the soil in situ and in real time: fluid dynamic gauging (thickness, voidage); millimanipulation (adhesive strength, removal force); TOC assays (soil leaching); and droplet image analysis (fat and oil release). Swelling of the soil was accompanied by a reduction in soil strength and preceded the release of oil droplets: the latter did not affect removal forces. The effect of pH, temperature, and surfactants (CTAB, SDBS and TX-100) was investigated and quantified using simple zeroth and first order kinetic models. Whilst increasing temperature from 20 degrees C to 50 degrees C enhanced swelling and reduced adhesion forces, the impact of pH and surfactant varied and simple rules to predict cleaning of this complex food soil could not be extracted. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

This study investigated the mechanisms involved in cleaning heterogeneous, multicomponent baked food soil off stainless steel surfaces in aqueous solutions. The results showed that swelling of the soil led to a reduction in soil strength and preceded the release of oil droplets. Temperature had a significant impact on swelling and adhesion forces, while the effects of pH and surfactants varied.