There’s a basic test used to identify bodily secretions at crime scenes. It’s not the only test, but it is useful in primary investigations — unless you spill a lot of commercial flour around.
Chocolatiers use yeasts to ferment the cocoa when making their tasty confections, which helps guard against the occasional bad-tasting batch. Those same yeasts can also be used to alter the aroma, providing a new means of making designer chocolate tailored to match your favourite flavours.
A rose is a rose is a rose, except when it’s actually a yeast. A company called Gingko BioWorks in Boston is partnering with French fragrance company Robertet to create a genetically modified yeast that makes the rose oil used in perfumes.