Biofilm Properties and Their Implications for Cleaning Processes in the Food Industry - A Review

Cleaning operations are carried out regularly throughout the food industry to remove deposits and microorganisms. Still, biofilms may persist in production plants, with potential negative implications for food safety and quality as well as economic disadvantages for companies. Consequently, the elimination of biofilms is crucial to ensure unrestricted operations. However, mechanisms involved in biofilm removal are still poorly understood, limiting the development of corresponding countermeasures. Therefore, this review focuses on biofilm properties and their implications for the removal process, as a basis for identifying and deeper understanding of the key factors relevant to cleaning strategies. In terms of rheological biofilm characterization, parameters such as elastic modulus and critical strain indicate the stress a biofilm can withstand. Biofilms with lower elastic modulus and crossover points are generally easier to remove. Assessing binding forces is crucial, as effective removal requires overcoming these forces. Further investigation of biofilm porosity may ultimately contribute to the development of targeted removal strategies. Multispecies biofilms grown dynamically show the highest cleaning resistance, with flow characteristics significantly influencing biofilm properties. Parameters from structural characterization methods cannot be directly translated into cleaning practices; however, they are still relevant to obtain deeper information on biofilm systems and their behavior. Exemplarily, modelling and simulation rely on precise material properties, enabling further conclusions relevant to cleaning and disinfection applications. Therefore, deeper insights into the microscopic and macroscopic properties of biofilms will contribute to the development of more targeted and efficient cleaning strategies.