Supplementary Material for World Mycotoxin Journal: Probiotic and mycotoxin reduction potentials of heat-tolerant Pichia kudriavzevii strains from maize- and sorghum-pap

Pap, a gruel prepared by treatment of ogi with boiling water, is widely consumed across West Africa and in the diaspora. It is, however, unknown whether probiotic strains with multi-functional properties can survive the preparation process of pap from ogi. Thus, this study aimed to select the surviving yeasts during the preparation of pap by heat treatment of maize- and sorghum-based ogi, and to screen the yeasts for their probiotic and multi-functional attributes including in vitro mycotoxin reduction potential. Four Pichia kudriavzevii strains out of 16 yeast isolates, including Kurtzmaniella natalensis and Kurtzmaniella quercitrusa, which survived the heat treatment of ogi to form pap, passed the probiotics selection criteria. These P. kudriavzevii strains were non-haemolytic, utilized bile salt efficiently, and survived 0.3% and 0.5% bile salt concentrations, pH 2.5, gastric and intestinal conditions at 100-104% and 99-104%, 92-99%, 88-92% and 102-121%, respectively. The strains also exhibited up to 97% potential for gut colonization through adherence to hydrocarbons, auto-aggregation activities at 98-100% after 24 h, and co-aggregation of notable foodborne pathogens. In addition, the strains were tolerant to 50 °C incubation for 12 h. The strains’ intact cells and cell-free extracts revealed strong potentials to scavenge and reduce free radicals. LC-MS/MS analysis confirmed that the strains simultaneously reduced the levels of 31 mycotoxins in liquid medium in a 48-h experiment by 1-87%, which is tentatively explained through the efficient adsorption to the cell wall and subsequent metabolization. While reductions of 6-82%, 39-41% and 8-51% were observed for enniatins, sterigmatocystin and zearalenone, respectively, after incubation period of 1 h, all the other investigated mycotoxins were reduced by 1-96% at the 3-h timepoint. Probiotic P. kudriavzevii strains with multifunctional attributes are transferable to pap and other mild heat-treated products for consumer benefits.