Food losses is responsible for unnecessary greenhouse emissions and waste of resources such as water, land, energy and inputs. Therefore, limiting food losses is of major interest to limit climate change and ensuring food security and sustainability. Nearly one‐third of all food produced worldwide is estimated to be lost postharvest, and much of this loss can be attributed to microbial spoilage. The spore-forming bacteria of the Bacillus subtilis group (B. subtilis) are among the most commonly identified species in the spoiled heat-treated food such as bakery and dairy products leading to high economic losses for the food and feed industry. The recurrence of Bacillus contamination is largely due to their ability to sustainably contaminate surfaces, particularly because of the spores' ability to strongly adhere to all types of materials and to resist hygiene procedures. To control this food-spoilage agent, it is therefore required to better describe the surface layer of spores interacting with contact materials of processing plant facilities. In B. subtilis, this layer is mainly made of proteins and glycans. While the crust proteins and their interaction network are now well established, the localization, nature and structure of glycans remain almost unknown. The SOGLOSSI project proposes a multidisciplinary approach combining microbiology, genetic, glycobiology and fluid mechanics at laboratory and pilot scale to I/ characterize the structure and the anchoring of the crust glycans of B. subtilis, II/ evaluate the role of each glycan in spore / contact material interactions and III/ evaluate the impact of processing and hygiene procedures on spore surface glycans and their consequences on spore / contact material interactions. To address the first objective, the crust glycans of several B. subtilis strains (including strains isolated from food industry) will be separated by chromatography and the structure of each glycan will be resolved by the combination of mass spectrometry and NMR methods. The putative glycosylation sites of the crust proteins will be defined by directed mutagenesis and glycoproteomic approaches. To address the second objective, the crust glycans structure of several mutant stains (available at PIHM) will be resolved by the methodology described above and the spore / contact material interactions forces will be measured for each mutant by using a flow-cell. These parallel approaches will make it possible to define the role of each glycan in the interactions between spores and contact materials. To address the last objective, a dedicated test rig will be manufactured to submit B. subtilis spores to conditions encountered in food processing (flow rate, temperature, pH) and evaluate the impact of these parameters on spore glycans and the consequences on spore adhesion. This knowledge will be used to develop alternative production and cleaning methods that are more effective in terms of surface hygiene control and more environmentally friendly, such as flow foam cleaning with bio-based surfactants that will be tested on a pilot scale. This project will generate fundamental knowledge about the structure and properties of the surface glycans of B. subtilis spores. It will also have major economic and environmental outcomes. The data obtained through this project could be used to optimize transformation and hygiene procedures in the food processing industries that faced recurrent contamination by spore-forming bacteria of the B. subtilis group. They should also help to develop mild-processing techniques and green hygiene solutions which are essential I/ to reduce the economic and environmental impact of these processes and II/ to improve the organoleptic, nutritional and health quality of processed food while limiting food spoilage.