The main safety issue of cereal grains is mycotoxin contamination. There is no published information about mycotoxin contamination of organic wheat in the United States. This study quantified the contents of deoxynivalenol (DON) and ochratoxin A (OTA), two frequently occurring mycotoxins, in organic wheat samples collected from six counties in North Carolina by enzyme‐linked immunosorbent assay (ELISA) and high‐performance liquid chromatography (HPLC). By ELISA, all samples were DON and OTA positive, and the DON contents in the flour and bran samples were 0.7–2.35 ppm and 5–8 ppm, respectively, while OTA in the flour and bran samples were 9.54–25.55 ppb and 21.67–32.55 ppb, respectively. By HPLC, the DON detected in flour and bran were 0.24–0.47 ppm and 0.35–0.83 ppm, respectively; all flour samples were OTA negative, but 5 out of 6 bran samples were OTA positive (0.48–1.28 ppb). More studies with larger sample number are needed to obtain representative results.
Practical applications
This study provides preliminary results about the DON and OTA in organic wheat grains. The results indicate that the organic wheat produced in North Carolina during 2018 season were contaminated by DON and OTA to various degrees. However, the concentrations of these two mycotoxins determined by ELISA were significantly higher than those determined by HPLC. Therefore, to avoid overestimation or underestimation, it is important for researchers and regulatory agencies to conduct multi‐lab studies to develop and standardize analytical methods and detailed procedures for accurate DON and OTA quantification. Regardless of analytical methods, all bran samples showed higher DON and OTA concentrations than flour samples. Thus, when using organic wheat bran or whole wheat as food or feed ingredients, the level of bran inclusion should be controlled to protect consumers and animals from mycotoxicosis.
