Optimisation of Bacillus cereus biofilm removal in the dairy industry using an in vitro model of cleaning‐in‐place incorporating serine protease

This article addresses a major hygienic issue in the dairy industry, namely biofilm removal. Response surface methodology was deployed to optimise Bacillus cereus biofilm removal conditions using serine protease. The currently practiced alkali cleaning‐in‐place (CIP) method was also optimised, and while the optimised protease CIP resulted in complete removal of biofilm cells, the reference CIP (with alkali) resulted in a reduction of 4.08 log biofilm cells/cm² and the optimised alkali CIP resulted in a reduction of ～4.92 log biofilm cells/cm². Furthermore, the amount of the biofilm matrix removed in the optimised protease CIP was significantly higher than that of alkali CIP. It was concluded that the optimised protease CIP has better applicability.