Approximately 1 billion metric tons of food are lost each year due to mycotoxins (FAO 2013), secondary metabolites produced by fungi (Marin et al. 2013) that contaminate crops (Placinta, D'Mello, and MacDonald 1999) and threaten the health of domestic animals and humans (Sobrova et al. 2010). The fungus "Fusarium graminearum" produces the mycotoxin deoxynivalenol (DON), which can be found in wheat, barley, and corn worldwide (Tanaka et al. 1988). In domestic animals, DON causes feed refusal, skin disorder, diarrhea, and reduced growth; in humans it can cause nausea, fever, headaches, and vomiting (Pestka 2010). The authors developed this unit to provide an interactive, interdisciplinary exercise for advanced secondary school students to detect DON in common food products, and to examine ways that mycotoxins affect crops, individual consumers, large groups of people, and domestic animals. Introducing students to the dangers of mycotoxins while encouraging them to think critically about issues important to agriculture, food safety, and biotechnology aligns the activity with the "Next Generation Science Standards." After completing the unit, students should be able to: (1) understand the potential for feed and food contamination; (2) discuss different methods for detecting mycotoxins; (3) consider principles of experimental design when sampling feed and food for mycotoxins, including potential pitfalls and limitations; (4) conduct an experiment to detect the mycotoxin DON in common grocery store products and samples of wheat, barley, and corn naturally contaminated with DON; and (5) discuss ways to detect and control mycotoxins in commercial settings.