Host foods and associated microorganisms contain water which in the vacuun of an electron microscope would rapidly evaporate at ambient temperature . In addition constituent fats may melt under the electron beam. Cryopreservation and examination at low temperature avoids these problems. The structure of emulsified or foamed products can be revealed by freeze-fracture techniques. Products such as ice cream which are not stable even under normal pressures at ambient temperature can be prepared rapidly and examined for prolonged periods.
Sargent, J. A.
"The Application of Cold Stage Scanning Electron Microscopy to Food Research,"
Food Structure: Vol. 7
, Article 2.
Available at: http://digitalcommons.usu.edu/foodmicrostructure/vol7/iss2/2