Microbial loads, mycotoxins, and quality of durum wheat from the 2001 harvest of the Northern Plains region of the United States

The 2001 durum wheat crop grown in the Northern Plains was surveyed for microbial loads, mycotoxins, and quality. Correlations among these factors were identified. Effects of cleaning, milling, and pasta processing on microbial loads and deoxynivalenol (DON) concentrations were determined. Aerobic plate counts (APCs), mold and yeast counts (MYCs), internal mold infection (IMI), and internal Fusarium infection (IFI) were lowest in grain samples from Montana and highest in grain from northeastern North Dakota. DON and 15-acetyldeoxynivalenol (15-ADON) were not detected in samples from Montana. Nivalenol was not detected in any samples. DON in North Dakota samples ranged from none detected to 23 mug/g. 15-ADON was detected in a few North Dakota samples, with a maximum of 0.8 mug/g. DON positively correlated with APCs, MYCs, IFI, damaged kernels, total defects, U.S. grade number, and tombstone kernel content and negatively correlated with test weight, vitreous kernel content, and kernel weight. APCs, MYCs, and DON concentrations were lower in semolina than whole grain. Processing semolina into spaghetti did not change DON concentrations. APCs for spaghetti were reduced 2.2 to 4.1 logs from those for semolina, whereas MYCs were reduced 0.1 to 1.7 log. Some APCs in durum flour and semolina were higher than certain industry specifications would allow, although other factors were acceptable. However, microbial loads in the spaghetti were all within specifications found in the available literature.