Ochratoxin A (OTA) is a mycotoxin of significant health concern that is present in a variety of cereal grains and other foods around the world. Although OTA contamination can occur prior to harvest, it is largely considered a storage issue that can be controlled through the implementation of proper storage practices. Barley, durum, and hard red spring wheat samples that had been stored for various lengths of time were collected (n = 262) over a period of 2 years by multiple commercial grain companies located in the northwestern and northern Great Plains regions of the United States. Samples were analyzed for OTA concentration using high-performance liquid chromatography with fluorescence detection. OTA was detected in 12.2% of the samples, and of those samples, 81.3% had been stored for ≥6 months. One sample of barley and four samples of wheat exceeded 5 ng/g of OTA.

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.

Ochratoxin A (OTA) is a toxin produced by some Penicillium and Aspergillus species around the world in a variety of food and feed, especially cereal grains, before harvest but primarily during storage. Durum and hard red spring (HRS) wheat samples were collected right after harvest as part of the U. S. regional crop quality survey in both 2011 (n = 560) and 2012 (n = 654) from the upper Great Plains. All samples were analyzed for OTA contamination using high-performance liquid chromatography with fluorescence detection. Overall, 2.1% of the samples were positive for OTA. In 2011, OTA was detected in 1.0% of the durum wheat samples but was not found in HRS wheat. In 2012, 8.3 and 1.4% of the durum and HRS wheat samples, respectively, were positive for OTA. Of the 25 samples that had detectable OTA, 3 samples (12%), all of which were durum wheat, had OTA that exceeded 5 ng/g.