Purpose: The purpose of this study was to determine the prevalence and level of OTA in barley, durum and hard red spring (HRS) wheat grown in the Northern Great Plains and northwest regions of the United States and stored under natural conditions.
Methods: Barley (n = 60), durum (n = 58) and HRS (n = 144) wheat samples (~1 kg) that had been stored for < 1-16 months were collected over two years by multiple commercial grain companies. Samples were analyzed for OTA using high-performance liquid chromatography with fluorescence detection. The binomial proportions obtained for each grain type were tested for significance between harvest years with the Chi-square test using SAS software.
Results: OTA was detected in 32 (12.2%) of the samples and of those samples 26 (81.3%) had been stored for ≥ 6 months. One barley and four wheat samples exceeded the European Union limit of 5.0 ng/g OTA. In 2012, the number of OTA positive durum and HRS samples decreased but barley increased as compared to 2011; a significant (P < 0.05) difference in proportions between years for HRS only.
Significance: To our knowledge this is the first study in the United States that targets OTA in barley and wheat stored under natural conditions. The information garnered in this study provides valuable insight as to the annual variation that occurs in the cereal grain supply as well as the actual OTA levels entering the food chain which, ultimately, reach the consumer.