Quantifying the cleaning efficiency of an industrial biofilm and an imitations on two types of stainless steel substrates

The formation of biofilms represents a significant hygiene risk in the food industry, as they are highly resistant to external influences and can cause health hazards while negatively affecting surface quality.Conducting cleaning trials with biofilms in an industrial environment is impractical due to the risk of contamination.For this reason, a cleaning test using a microorganism-free biofilm imitation was developed.In a cleaning study, industry-relevant biofilms of Microbacterium lacticum and a biofilm imitation were compared.The biofilm imitation consists of organic substances such as alginate, xanthan gum and CaCl2 which occur in the exopolysaccharide matrix of biofilms.These components form a highly hydrated, viscoelastic gel that ensures the mechanical stability of the biofilm.Cleaning was carried out on stainless steel substrates using a robot-controlled spray jet, supplemented by prior treatment with an alkaline foam cleaning at room temperature for 10 minutes.The results showed that both the biofilm and the biofilm imitation had a similar macroscopic cleaning rate under the tested cleaning conditions with approximately the same layer thicknesses in the wet state of approx.500 m.Stainless steel surfaces of varying roughness have been analysed to take account of practical and extreme industrial conditions.Increasing the roughness of the stainless steel substrates had no effect on the macroscopic removal of soiling.