Gamma rays belong to the electromagnetic wave spectrum, similar to light, infrared, or ultraviolet rays. However, gamma rays distinguish themselves by their shorter wavelength, which results in higher energy levels. There are many gamma irradiation plants in India. 

During irradiation, this heightened energy is transferred to the electrons within the molecules of the products, leading to the creation of highly reactive radicals. This phenomenon is the basis of ionizing radiation. These free radicals subsequently disrupt the DNA of existing microorganisms, rendering them incapable of reproducing and causing their demise. Consequently, the irradiated product becomes sterile. 

Crucially, gamma rays exclusively impact the electron shell of the molecule, making it physically impossible for the radiated product to become radioactive itself. 

The amount of energy absorbed during radiation is quantified in Kilograys (kGy). This absorbed energy is contingent upon various factors, including the duration of exposure, radiation dosage, material density, and package size. It is monitored using a dosimeter, guaranteeing that each product receives the designated radiation dose.  

The sterilization processes 

Presently, all industrial gamma irradiation services and processing facilities utilize Cobalt-60 as the source of gamma radiation. The preference for Cobalt-60 arises from its gamma rays possessing relatively high energy and its relatively extended half-life, which spans 5.27 years. 

In a prior installment, we initiated our series on gamma radiation sterilization methods with a focus on heat-based methods, particularly autoclaving. Subsequently, we delved into non-heat methods, such as Ethylene oxide (EtO) and Formaldehyde, which are employed for sterilizing items sensitive to heat. These two methods deploy chemical agents for gamma irradiation sterilization. 

Much like EtO and formaldehyde, gamma radiation sterilization is categorized as a ‘Cold Process.’ This means that the temperature of the treated product remains relatively unchanged, making it a suitable method for sterilizing heat-sensitive items. Gamma irradiation sterilization operates independently of humidity, temperature, or pressure and can be applied to packaged goods. 

Gamma irradiation sterilization represents a physical/chemical sterilization method. It eradicates bacteria by breaking down bacterial DNA, impeding bacterial replication. The energy carried by gamma rays traverses the equipment, disrupting the pathogens responsible for contamination. These molecular-level alterations lead to the death of the contaminating organisms or render them incapable of reproducing. Importantly, the gamma radiation sterilization process does not leave behind residues or introduce radioactivity into the treated items. The extent of penetration achieved depends on the material’s thickness. 


Gamma sterilization process is predominantly employed in the healthcare sector. It is used to disinfect a wide range of medical tools and products. It helps make tools free from micro-organisms as well as restricts reproduction of bacteria from further contamination. 

Gamma radiation sterilization is also applied to items like plastic syringes, hypodermic needles, scalpels, surgical blades, adhesive dressings, and heat-sensitive medications. 

Additional applications encompass syringes, surgical gloves, gowns, masks, adhesive bandages, dressings, ‘tetrapacks,’ bottle teats for premature infants, food packaging, raw materials for pharmaceuticals and cosmetics, and even wine corks. 

A commonly encountered application of gamma irradiation sterilization is in the food industry.
Symec Engineers Private Limited enables food and healthcare businesses to harness the benefits of gamma irradiation sterilization technology.