This study examines the epistemic disciplinary knowledge that students consider when addressing a real food emergency that requires their engagement in inquiry and argumentation practices. The study comprised two phases: (1) designing an experiment to study the emergency and (2) evaluating the real outcome of the emergency. The participants were 10th and 11th grade students (15-17 years old) working in small groups in the subject of Biology. Their conversations were examined through discourse analysis, for which two rubrics were developed, one for each phase of the task. The design phase related to the scientific practice of inquiry while the evaluation phase related to the scientific practices of inquiry and argumentation. The results suggest that not all the epistemic disciplinary knowledge promoted by the task was taken into consideration by students, especially in relation to the reproducibility of experiments and its feasibility to solve socio-scientific issues. This implies that epistemic disciplinary knowledge must be addressed in the classroom through an explicit-reflexive approach. Further directions and implications for biology teaching are provided.