Accelerators work on the same principle as a television tube. Instead of being widely dispersed and hitting a phosphorescent screen at low energy levels, the electrons are concentrated and accelerated to 99 percent of the speed of light. This produces rapid reactions on the molecules within the product. The Electron Beam Linear Accelerator machine generates and accelerates electrons to energies of 5.0, 7.5, or 10.0 MeV with beam power of up to 10kW.
A stainless steel plate may be placed under the scanning
horn to convert the electrons to X-rays at an energy level of 5 MeV to allow
very thick penetration at low doses; however, this increases irradiation
time considerably.
A cart system moves the products to be irradiated under the electron beam at a predetermined speed to obtain the desired dosage. Multiple carts move products in and out of the irradiation area continuously with throughput up to 500 pounds per hour. Maximum product dimensions are 24 inches wide and 36 inches long. Product thickness depends on density and electron energy. For example, 3.5 inches is the maximum thickness for meat. Using X-rays increases thickness to several feet for various products.
To request irradiation services, please contact Mike
Holtzbauer, 515-294-6334 (phone), 515-294-6328 (FAX),
mholtz@iastate.edu
, or 194 Meat Laboratory, Iowa State University, Ames, IA 50011-3150.
The ISU
Meat Laboratory
is attached the the accelerator facility and has complete slaughter, cutting
and processing operations with refrigeration and frozen storage. Contract
research and/or irradiation services are available. An Analytical Laboratory
is available for chemical, dosimetry, sensory, microbiological, and physical
analyses on a per sample fee basis. In addition to meat, irradiation services
can be conducted on a wide variety of fresh vegetables, fruits, and spices,
as well as selected nonfood industrial products.
Test markets are conducted to determine consumer acceptance and their willingness to pay for irradiated food. This research includes assessments of the effectiveness of informational techniques in increasing consumer understanding and acceptance of irradiated food.
Researchers study the amount of irradiation needed to reduce spoilage organisms and to eliminate pathogenic bacteria, parasites, and viruses in muscle foods. Other pasteurization techniques combined with irradiation are under study. Extension of shelf-life is being studied to eliminate molds and prevent sprouting.
Research on packaging, temperature, freshness, and
additives is conducted to optimize the irradiation process. Studies are
in progress to determine the effects of irradiation and environmental factors
on color, flavor, odor, and texture of food
Visit the Iowa State University Homepage
or the ISU Department of Animal Science
.