FNH 200 Lecture Notes - Lecture 10: Canadian Food Inspection Agency, Food Irradiation, Canadian Nuclear Safety Commission
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The exposure of food to ionizing energy, more commonly known as food irradiation, is
a preservation technology that has generated much public debate. In this lesson you
will learn important definitions relating to the technology. The types of sources of
ionizing energy and irradiator layout will be introduced. You will learn about the current
regulations regarding the use of ionizing energy for food preservation in Canada and in
other countries. We will explore a number of issues and controversies about the use of
ionizing energy in the food industry. When you have completed this lesson, you should
have a sound understanding of ionizing energy as a preservation technology and be
familiar with the issues that have been raised in the popular press.
Upon completion of this lesson you will be able to:
Understand the concept of food irradiation as a food preservation method;
Define key terms used in conjunction with preservation of food with ionizing
Describe the principles for determining the required irradiation dose depending
on the desired outcome
Describe the principles for determining wholesomeness and safety of irradiated
Learn about current regulations, and what food products are approved for
irradiation in Canada versus other countries
Articulate a personal set of values pertaining to the use of ionizing energy in food
Smith, J.S. and Pillai, S. 2004. Irradiation and Food Safety. (A scientific status
summary). Food Technology, 58(11): 48-55
Division 26, Food Irradiation. Food and Drugs Act, and the Food and Drug
Guide to Food Labelling and Advertising. Section 2.14.1. Food
Irradiation.Canadian Food Inspection Agency.
Food Irradiation- by the Canadian Food Inspection Agency. 2012
Frequently Asked Questions Regarding Food Irradiation on the Health Canada
website (last updated 2002/11/25)
Aside from the use of genetically modified organisms in foods, there is perhaps no
other method of food preservation that has generated as much heated debate recently
as food irradiation. Although the basic concept of food irradiation as a food
preservation technology is not new (a patent for food preservation by irradiation was
applied for in the United States in 1921), it is nonetheless a controversial method of
Much of the controversy about food irradiation seems to stem from a fear of the
unknown and unfamiliar - we have often seen references in media reports of food
irradiation associated with radioactive fallout, accidents at nuclear power plants and
concerns about nuclear war and weapons testing. This has led to further confusion in
the minds of the general public about food irradiation and what the process actually
involves. Upon completing this lesson, you will have a good knowledge of what food
irradiation is, what its potential applications are, the physical process of food
irradiation, and limitations and advantages of food irradiation as a method of food
What is radiant energy?
Radiation refers to the emission and propagation of energy through matter or space
by electromagnetic disturbances. These forms of energy are found within the the
electromagnetic spectrum of radiation (Figure 10.1). This is an organized scale
where we find energy ranging from radio waves, microwaves, visible light to ionizing
radiation. Each of these forms of energy vary in frequency, wavelength, energy value,
penetrating power, and their effects on biological systems.
Figure 10.1. The Electromagnetic Spectrum
Adapted from: Purves et al., 1992. Life The Science of Biology (3rd ed.), Ch. 8. Sinaur
Associates, Inc., Sunderland, Mass., p. 164.
The longer wavelengths of electromagnetic energy that we are familiar with include
visible light, infrared and ultraviolet rays. These are characterized by having low
penetrating power. Microwaves and infrared radiation are two examples of the longer
wavelengths in the electromagnetic spectrum.
Microwaves are used in food for their heating properties. The microwaves travel in
straight lines and pass through air, glass, paper and plastic, but reflected by metals.
They are readily absorbed by water (polar molecule), causing it to vibrate. Heat is
generated by the intermolecular friction generated from the vibrating water (polar)
molecules in food. Microwaves are absorbed by food up to a depth of 5 to 7.5 cm.
Infrared energy can generate heat. They can reach temperatures above 100°C.
Typical examples of infrared energy can be seen in ovens, toasters, and even those