GS Paper III

News Excerpt:

The Tamil Nadu government issued an advisory banning the use of liquid nitrogen in food and warned of stringent action against violators.

About the news::

• A week ago, a video of a child screaming went viral on social media. There were visuals of adults spewing white smoke from their mouths and noses.
• It was soon apparent that the child had consumed a food item infused with liquid nitrogen.
• The Tamil Nadu Food Safety Department cited the Food Safety and Standards Regulations, and the Drug Administration Department issued a circular on the use of liquid nitrogen.
• The substance can only be used to preserve packaged food, the circular explained. The department also warned of stringent action, including fines and legal proceedings, if it is used for other purposes.

Liquid nitrogen:

• Liquid nitrogen is simply nitrogen that has gone from its natural gaseous state to a liquid state. It becomes liquid when its temperature goes below, around -195.8°C.

How is liquid nitrogen made?

• Generally, industrial production of pure liquid nitrogen is achieved by distilling it from liquid air. Air is composed of oxygen (21%), nitrogen (78%), and a small percentage of other gases.
• To make the air liquid, it undergoes a liquefaction process by means of strong compression by pistons that inject the air, and then it is cooled to very low temperatures.
• Some 700 litres of air in the gaseous state condense into just 1 litre of liquid air.
• Nitrogen and other liquid gases are stored in Dewar containers(Insulated cryogenic containers), which are pressurised vessels that provide high thermal insulation.

Industrial uses of liquid nitrogen:

• In the construction and maintenance of public works, liquid nitrogen is used to temporarily freeze a section of pipe and thus prevent its contents from spilling out when opening it to carry out some work. It can also be injected into an area where a crack has been covered with sealing material, producing a plug of frozen matter to buy time and let the repair be fixed.
• It is also used for manufacturing electronic components and as a shielding gas in welding processes.
• In laboratories for various fields, it is used to remove solvents or water in a gaseous state using cold traps.
• Liquid nitrogen is used to conserve and store semen, both animal and human. This technology is crucial for sperm banks that are used in artificial insemination.
• In the food industry, it is used in deep-freezing processes for vegetables and animal products, which enables preservation and transportation.

Liquid nitrogen in cancer care:

• Liquid nitrogen, an inert, colourless, odourless cryogenic fluid has traditionally been used in the management of many benign pre-cancers and cancers since the 1960s.
• This form of treatment is generally used to manage cancers wherein conventional surgery is not possible or can be used as an adjunct to conventional surgery.
• The procedure involves using the element at a very cold -196 degrees C to freeze and destroy cancer cells. The treatment is scientifically described as cryotherapy. It can also be used to obtain biopsies from cancer tissues for further molecular analysis.
• Another application is cryo-adhesion to remove foreign bodies. During this treatment, liquid nitrogen or any other cooling agent is brought in proximity/contact with the cancerous tissue through several techniques, i.e. open spray, cone, dipstick or tweezer.
• Liquid nitrogen is subsequently pumped to freeze and immediately left to thaw. This process of freezing and thawing is repeated several times to [kill] the cancer cells, largely due to the formation of intracellular ice crystals, which will eventually swell, blister, and crust out.
• Cryotherapy has been attempted to treat many cancers, including those of skin, bone, breast, cervical, eye, kidney, liver, lung, and prostate.

Potential hazards due to Liquid nitrogen:

• Liquid nitrogen can scorch the organ or part of the body it contacts, making it appear like frostbite. It can damage the lips, tongue, throat, lungs, and stomach, causing lesions or burning tissues.
• If it reaches the stomach, the organ could get perforated. In the lungs, it could produce CO2 and the person could become unconscious. It could even prove fatal.

Conclusion:

Liquid nitrogen should be handled by trained professionals with proper protective gear, preferably in a controlled lab or industry. Improper handling or consumption of liquid nitrogen can cause severe damage to the skin, mucous membranes, and internal organs.