• Gamma Rays: Cobalt 60
• Electronic Beam
• X-Ray 

Advantages and Disadvantages of food irradiation

Advantages

• Terminal Processing: Due to the penetration depth of the ionizing radiation, the products can be processed in fully sealed, final packaging. This limits risk of contamination after the sterilization.
• Cold Method/Temperature Independence: Radiation sterilization has no heat dependence and is efficient at ambient temperature and sub-zero temperatures also. It is also compatible with temperature-sensitive materials, such as pharmaceuticals and the biological samples.
• Chemical Independence: No volatile and toxic chemicals are needed for radiation. In the case of X-ray or e-beam irradiation, no end products which require disposal are generated during the procedure.
• No residue: Radiation does not leave residue on the sterilized product.
• Flexibility: Radiation can sterilize the products of any phase (gaseous, liquid, or solid materials).
• Time efficiency: The E-beam sterilization can be completed in seconds to minutes.
• Sterility assurance level (SAL): Radiation treatment yields a high SAL of 10^-6 or better, which ensures that less than one out of a million microorganisms survive the sterilization procedure.

Disadvantages

• Instrumentation: The capital costs are high and specialization facilities are often needed. Gamma radiation requires a nuclear reactor; E-beam/X-ray radiation is generated by using electron beam accelerators.
• Product Degradation: Radiation-based methods are not compatible with all the packaging materials and can cause its breakdown.
• Radioactive material: Radiation sterilization requires handling and disposal of the radioactive material.