Corrin-based chemosensors allow the rapid and selective colorimetric detection of endogenous biological cyanide. The color change from orange to violet can be easily observed with the "naked eye" (Deltalambda(max) = 51 nm). The methodology works directly in the biological matrix without time-consuming sample pretreatment and the use of special reaction conditions. It was possible to study the enzymatic release of cyanide from its biological precursor linamarin with diffuse reflectance UV-visible (DRUV-vis) spectroscopy on a freshly prepared biological surface. These experiments were accompanied by stopped-flow kinetic measurements under homogeneous conditions. Detection in the biological sample is based on the selective coordination of cyanide to the metal-based chemosensor as proven by UV-vis and (1)H NMR spectroscopy. Examples of applications during food manufacturing are given.