Cryoprotectant should be added to spores

Cryoprotectants should be added to spores before storing them in liquid nitrogen.
A cryoprotectant is a substance used to protect biological tissue from freezing damage.
Cryoprotectants are also used to preserve living materials in the study of biology and to preserve food products.
For years, glycerol has been used in cryobiology as a cryoprotectant for blood cells and bull sperm, allowing storage in liquid nitrogen at temperatures around -196°C.