Fluid Engineering for Food Security (FEFS) – FEFS

Contamination of surfaces of food processing lines by pathogens and spoilage bacteria is a major issue that has not yet found a proper cleaning and disinfection solution. Indeed, after hygienic procedures, adherent bacteria are still commonly found on surfaces, mostly in the form of adherent spores, e.g. Bacillus spores in closed equipment or in the form of biofilms, e.g. those partially composed of Pseudomonas spp. These adherent bacteria are known to be responsible for many food- poisoning, thus underlining the needs for implementing more efficient procedures associated with a better understanding of the underlying mechanisms. Thanks to an ongoing collaboration, it has been recently shown by the partners that the drying conditions play a major role on the persistence of surface contamination. The goal of the proposed research is to bring researchers with complementary skills, the opportunity to work on this specific problem that begs a concrete technological solution. The project focuses on key research ideas of combined biology, fluid mechanics and advanced metrology (i) to improve the comprehension of bacterial adhesion in complex industrial environments and (ii) to propose optimal hydrodynamic solutions (based on interfacial flows) to remove adherent bacteria (bacterial spores used as a model) in industrial equipment without overuse of chemical products. The approach will consist of (a) characterizing the dynamical evolution of spore adhesion forces during drying/wetting cycles in their complex environment and unveiling the origin of these forces and (b) determining the optimal two-phase flow configurations capable of efficiently removing spores. The issue (a) will be tackled through precise real-time monitoring of (i) the evolution of spore adhesion forces during wetting/drying cycles with micropipettes and microfluidic based systems and (ii) the kinetics of interaction between spores and substrates in connection with their respective wetting properties thanks to the observation of interfaces by confocal and electron microscopy, the observation under optical microscope of the spore detachment in flow cells and the development of dedicated acoustical sensors. In the part (b), the numerical (Boundary Integral Method) and experimental (at microscopic and pilot scales) tools will allow the determination of optimal two-phase flows capable of detaching any adherent bacteria from various materials. Such flows would prevent the unnecessary overuse of chemicals for equipment disinfection and, therefore, contribute to the implementation of greener industrial processes.
Intellectual Impacts: The multidisciplinary consortium includes international collaborators and the synergies are fully complementary. The partnership will advance sciences on multiphase fluid and bacterial contamination of surfaces, with several technological applications including bio-sensors, multiphase flow cleaning processes and control of equipment hygiene for a multitude of industries related to agriculture, pharmaceuticals, metallurgy and energy. Some key science issues associated with bacteria adhesion to food production lines and instabilities in multiphase flows will be resolved. The proposed collaboration would promote further partnerships between industry and academe.
Broader Impacts: The project will enhance the training of young scientists in cutting edge international research settings. Dissemination will be achieved by journal publications, webinars and web sites.
Transfer of Knowledge: The combined expertise of international institutes will result in transfer of knowledge via site visits and workshops. It will include the numerical and analytical methods as well as the experimental techniques associated with microfluidics and microbiology. The transfer of knowledge will take place in both directions and will become the permanent foundation for sustained collaboration.