Model food soils for investigating cleaning: A review

Cleaning operations are performed regularly throughout the food industry. This review focuses on the removal of strongly adherent fouling deposits which compromise the performance and hygienic status of equipment and processes. Identifying and understanding the key mechanisms involved in cleaning food deposits is essential for selecting and optimising cleaning protocols. The complexity of these materials has prompted the use of model soil-surface systems for experimental investigations of cleaning. The factors that need to be considered in selecting model soil systems, the techniques used to measure and characterise cleaning, and the formulations that have been used to model food fouling deposits are discussed. Particular focus is given to deposits formed from liquid foods high in protein, starch, sugar and lipids. Biofilms, fouling layers generated in membrane operations and corrosion fouling are not considered.