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ARS Home » Southeast Area » Dawson, Georgia » National Peanut Research Laboratory » Research » Publications at this Location » Publication #367570
Research Project: Integration of Traditional Methods and Novel Molecular Strategies for Improving Disease Resistance and Input-use Efficiency in Peanut

Location: National Peanut Research Laboratory

Title: Novel foodborne source of Xerochrysium xerophilum (Pitt) Pitt, raw peanuts stored at low moisture and high CO2

Author
item Arias De Ares, Renee
item Orner, Valerie
item Sobolev, Victor
item Massa, Alicia
item Faustinelli, Paola
item Walk, Travis
item Lamb, Marshall
item Butts, Christopher - Chris

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2024
Publication Date: 7/14/2024
Citation: Arias De Ares, R.S., Orner, V.A., Sobolev, V., Massa, A.N., Faustinelli, P.C., Walk, T., Lamb, M.C., Butts, C.L. 2024. Novel foodborne source of Xerochrysium xerophilum (Pitt) Pitt, raw peanuts stored at low moisture and high CO2. Journal of Stored Products Research. 108. Article 102381. https://doi.org/10.1016/j.jspr.2024.102381.
DOI: https://doi.org/10.1016/j.jspr.2024.102381

Interpretive Summary: In peanuts stored under dry conditions and very high concentration of carbon dioxide, we found a xerophilic fungus that had never been reported on peanuts. We report the environmental conditions at which this fungus can potentially become a problem in storage. In addition, we have identified for the first time what is called the "perfect form" or sexual stage of this fungus. This fungus that is named Xerochrysium xerophilum has been the subject of scientific research for more than 60 years, but its perfect form had never been observed before.

Technical Abstract: Peanut seed is ideally stored at low water activity (aw) and low temperature, since common mycotoxigenic fungi cannot survive below 0.8 aw, and the life cycle of seed-infesting insects is interrupted below 15 'C. Hermetic storage bags at 0.77 aw, room temperature, and = 9000 mg/m3 CO2, were tested for their potential use in countries where temperature control is unaffordable. Despite these inhospitable conditions, peanuts displayed an unusual white powder that we identified as the xerophilic fungus Xerochrysium xerophilum (syn. Chrysosporium xerophilum), and sequenced its genome. Previously, only 19 sequences shorter than 1700 nt were available. For six decades, only three food sources of X. xerophilum were known: dry prunes, chocolate, and dry coconut. Here we report peanut as a novel food source of this extremophile and make one isolate available at the USDA culture collection. Given the slow growth of this fungus in culture, we developed a robust Polymerase Chain Reaction(PCR) to sequence and identify X. xerophilum on contaminated peanut seed without performing DNA extraction. The broad range of oxygen, aw and temperatures that support growth of X. xerophilum will significantly affect the decisions made regarding the conditions to safely store peanuts.