title: Infestation and Quantification of Ochratoxigenic Fungi in Barley and Wheat Naturally Contaminated with Ochratoxin A.
abstract: Cereal grains are a significant source of ochratoxin A (OTA) in the human diet. Multiple ochratoxigenic Aspergillus and Penicillium spp. have been reported as contaminants on various cereal grains around the world, although relatively few species dominate in any given location. Efforts to mitigate the risk of fungal contamination and OTA accumulation can be made pre- and postharvest. Still, a rapid and reliable screening method is sought that can be used to predict the OTA level of a sample and to inform risk assessments prior to processing. In this study, we assessed the efficacy of two OTA-related indices for OTA level prediction. Infestation rates were determined by direct plating for freshly harvested and stored barley, durum, and hard red spring wheat samples (n = 139) with known OTA levels. Presumptive ochratoxigenic isolates were tested for their ability to produce OTA. The nonribosomal peptide synthase (otanpsPN) involved in OTA biosynthesis was used to quantify ochratoxigenic fungi in barley and wheat. Viable Penicillium verrucosum was present in 45% of the samples. In total, 62.7% (n = 110) of the P. verrucosum isolates tested produced OTA on dichloran yeast extract sucrose 18% glycerol agar. Both OTA level and infestation rate (r = 0.30), as well as OTA level and otanpsPN concentration (r = 0.56), were weakly correlated. Neither infestation rate nor otanpsPN concentration is a reliable predictor of OTA level in a sample.
authors.affiliation: Great Plains Institute of Food Safety, North Dakota State University, Fargo, North Dakota 58108, USA.
authors.forename: Julie
authors.initials: J
authors.lastname: Kuruc
authors.affiliation: Department of Plant Sciences, North Dakota State University, Fargo, North Dakota 58108, USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Hegstad
authors.affiliation: School of Food Science, University of Idaho, Moscow, Idaho 83844, USA.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Plant Sciences, North Dakota State University, Fargo, North Dakota 58108, USA.
authors.forename: Kristin
authors.initials: K
authors.lastname: Simons
authors.affiliation: School of Food Science, University of Idaho, Moscow, Idaho 83844, USA.
authors.forename: Dojin
authors.initials: D
authors.lastname: Ryu
authors.affiliation: Great Plains Institute of Food Safety, Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, North Dakota 58108, USA. Charlene.Hall@ndsu.edu.
authors.forename: Charlene
authors.initials: C
authors.lastname: Wolf-Hall
mesh_terms: D001230:Aspergillus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D005506:Food Contamination / Q000032:analysis*; D001467:Hordeum / Q000737:chemistry* / Q000382:microbiology; D006801:Humans; D009183:Mycotoxins / Q000032:analysis / Q000378:metabolism*; D009793:Ochratoxins / Q000032:analysis / Q000378:metabolism*; D010407:Penicillium / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D014908:Triticum / Q000737:chemistry* / Q000382:microbiology
chemical_list: D009183:Mycotoxins; D009793:Ochratoxins; C025589:ochratoxin A