Effects of Five Filamentous Fungi Used in Food Processes on In Vitro and In Vivo Gut Inflammation

Food processes use different microorganisms, from bacteria to fungi. Yeast strains have been extensively studied, especially Saccharomyces cerevisiae. However, to date, very little is known about the potential beneficial effects of molds on gut health as part of gut microbiota. We undertook a comprehensive characterization of five mold strains, Penicillium camemberti, P. nalgiovense, P. roqueforti, Fusarium domesticum, and Geotrichum candidum used in food processes, on their ability to trigger or protect intestinal inflammation using in vitro human cell models and in vivo susceptibility to sodium dextran sulfate-induced colitis. Comparison of spore adhesion to epithelial cells showed a very wide disparity in results, with F. domesticum and P. roqueforti being the two extremes, with almost no adhesion and 20% adhesion, respectively. Interaction with human immune cells showed mild pro-inflammatory properties of all Penicillium strains and no effect of the others. However, the potential anti-inflammatory abilities detected for G. candidum in vitro were not confirmed in vivo after oral gavage to mice before and during induced colitis. According to the different series of experiments carried out in this study, the impact of the spores of these molds used in food production is limited, with no specific beneficial or harmful effect on the gut.