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This experiment exposed 3rd and 4th y undergraduates and graduate students taking a course in advanced food analysis to DNA extraction, polymerase chain reaction (PCR), and DNA sequence analysis. Students provided their own fish sample, purchased from local grocery stores, and the class as a whole extracted DNA, which was then subjected to PCR, gel electrophoresis, and Sanger sequencing. Students retrieved their sequences and identified their fish using the NCBI BLAST nucleotide database. Slightly more than half of the samples yielded sequences identical or close to expected (based on the identification of the fish on the packaging); some other samples matched unanticipated fish or other organisms, due to an incomplete database, minor sequencing errors, or laboratory contamination (human and fungal sequences); 1 canned tuna sample identified as hake could represent food fraud.

Fusarium head blight (FHB) is a devastating disease of wheat (Triticum aestivum L.) and other small grain cereals. The disease is caused by several species of Fusarium. This study was conducted to identify the major species of Fusarium causing FHB in Nebraska and to characterize isolates of the species for perithecia and deoxynivalenol (DON) production and for aggressiveness (quantified as disease severity and area under the disease progress curve) on spikes of two winter wheat cultivars. Isolates of Fusarium spp. obtained from wheat spikes and grain collected from FHB-affected winter wheat fields and grain elevators, respectively, in 2007 and 2008 were identified as Fusarium graminearum. The isolates varied widely in perithecia and DON production in vitro and in aggressiveness on wheat spikes of soft red winter wheat cultivars Coker 9835 (FHB susceptible) and VA04W-433 (moderately resistant). Fusarium head blight severity for the three most aggressive F. graminearum isolates was higher in Coker 9835 than in VA04W-433 during the first 7 d after inoculation (DAI) but was comparable in both cultivars from 10 to 21 DAI. Deoxynivalenol concentration and aggressiveness were positively and linearly related (R² ≥ 0.60, P < 0.05). Isolates that produced higher concentrations of DON were more aggressive than those that produced lower concentrations of the toxin regardless of wheat cultivar. [ABSTRACT FROM AUTHOR]