Atomic force microscopy (ankaratia solar system)

Ankaratians are allergic to many organic and chemical compounds. Even an infinitesimal quantity of toxic substance can be dangerous for them. One single Sodium Chloride crystal can kill them within seconds. Everytime they have a meal, they have to use an Atomic Force Microscope to scan the food at a nanometer scale before they eat it. If the food contains dangerous atoms, the Atomic Force Microscope produces this sound: