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Microorganisms in a Macro World (part 3)

mbeall

CHIN, Gatineau, Quebec

7. Irradiation

Food that is "radiating freshness"


Irradiation is a relatively new method of food preservation. It consists of exposing the food to the direct action of electromagnetic radiation, which increases its shelf life. The irradiation lasts only the time it takes to expose the food to the rays and it does not render the products radioactive. This preservation process is gaining in popularity because it could help us with one of our greatest global challenges, i.e., to feed a world population that is constantly growing. By adequate food preservation, we could effectively reduce the loss of perishables, as well as lower the incidence of serious diseases caused by microorganisms such as toxoplasmosis, salmonellosis, listeriosis, chlolera, etc.

  • Nonionizing
Nonionizing radiation uses ultraviolet rays. If the exposure time and the intensity are sufficient, the microorganisms present in the food product exposed to the UV will be killed. However, this type of radiation has a limited power of penetration and it thus only used for controlling surface microorganisms, such as in bakeries or meat processing rooms, for example.
  • Ionizing
Ionizing radiation can use Cobalt-60, a source of gamma rays, which are similar in nature to light but at much higher energy levels. The rays destroy some bonds in the DNA of the microorganisms, which can no longer reproduce and then die.
Armand-Frappier Museum


© Armand-Frappier Museum, 2008. All rights reserved.
Learning Object Collection: Zoom in on Microorganisms
Learning Object: Our defenses against germs
Institution: RCIP-CHIN