One unfortunate part of the story is that most cases of adulteration are pretty clumsy, and lives could have been saved if we had simple and widely available tests for contaminants.
They have taken some pretty old ideas and rejigged them to create a rather innovative testing system that can detect adulteration in liquid medicines and maybe even food.
A sensitive mass sensor, then, should be able to detect medicines that have not been produced properly.
What these researchers were looking for is a cheap alternative.
The principle remains the same, though: change the mass of the vibrating material, and the tone of the note it produces will change.
The mbira consists of a set of steel tines suspended over a sound box.