How does an electron beam irradiate food?

• A. Uses gamma rays emitted by cobalt-60
• B. Uses ultraviolet light to sterilize product
• C. Uses microwaves to heat the product
• D. Uses stream of high-energy electrons accelerated at near the speed of light to shower the product with electrons

Answer: (D)

Electron beam irradiation relies on a particle accelerator to produce a stream of high-energy electrons that are directed at the food and accelerated to nearly the speed of light. As these electrons pass through the product, they deposit energy along their path, causing ionization and molecular damage that disrupts microorganisms’ DNA and other critical components, leading to inactivation. This method can be turned on and off and does not leave any residual radioactivity, unlike gamma irradiation from a radioactive source such as cobalt-60. Ultraviolet light mainly affects surfaces because it has shallow penetration, and microwaves heat food by exciting water molecules, which is not primarily a method for microbial inactivation and can cause uneven heating. So, the irradiation works by showering the product with high-energy electrons to deliver the needed dose of ionizing energy.