Liquid nitrogen in foods draws Tamil Nadu’s ire, yet again Premium

A substance used to preserve food has found its way into consumption, raising safety concerns

Liquid nitrogen being poured from a container into a bowl. | Photo Credit: Cory Doctorow/Flickr

A week ago, a video of a child screaming went viral on social media. There were visuals of adults spewing white smoke from their mouth and nose. What the child said was garbled in the video, but it was soon apparent that the child had consumed a food item infused with liquid nitrogen.

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Television channels and online media took up the issue. The Tamil Nadu government issued an advisory banning the use of liquid nitrogen in food and warned of stringent action against violators.

In May 1991, The Hindu reported that a London-based company developed a system to improve the quality and shelf life of food. It introduced droplets of liquid nitrogen in the packaging on the production line. Since nitrogen’s volume expands 700-times when it evaporates, it displaces the oxygen in the food pack, preventing microbial action and preserving the freshness.

The technique was useful in packing coffee, potato crisps, peanuts and peanut butter, milk products, cheese, and dried potatoes, the article said.

As with every novelty, some chefs also experimented with liquid nitrogen to make food more interesting. In 2016, a few upmarket restaurants and eateries in Chennai and elsewhere used liquid nitrogen to entice customers.

The trend caught up in other parts of the country. In August 2017, the then Union Environment Minister Harsh Vardhan said in Rajya Sabha that the government would investigate the addition of liquid nitrogen in food and drinks served in some restaurants. He was responding to an incident in Gurgaon a few months prior, when a man drank a cocktail with liquid nitrogen at a pub and ended up with a perforation in his stomach.

Six months ago, in Tiruchirappalli, a vendor’s shop was sealed after authorities found liquid nitrogen in food, the designated food safety officer of the city said.

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,” Arvind Krishnamurthy, professor and head of surgical oncology at the Adyar Cancer Institute, said. “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 to use it as cryo-adhesion to remove foreign bodies,” he explained.

“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 formation of intracellular ice crystals, which will eventually swell, blister, and crust out,” Dr. Krishnamurthy added.

Cryotherapy has been attempted to treat many cancers, including those of skin, bone, breast, cervical, eye, kidney, liver, lung, and prostate.

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

A day after the viral video, 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 fine and legal proceedings, if it is used for other purposes.

(sujatha.r@thehindu.co.in)