Dragon's Breath – Take precautions when using liquid nitrogen in food and beverages
A novel food trend has been popping up in shopping malls, carnivals, fairs, and restaurants, using liquid nitrogen to create frozen desserts, or to produce vapour clouds when foods such as cereals and cookies dipped in liquid nitrogen are exposed to air, commonly known as “dragon's breath” snacks. Liquid nitrogen has long been used by the food industry to chill, freeze, and reduce microbial growth during manufacturing processes. However, using liquid nitrogen at the point of sale poses a risk of accidental exposure to consumers if they are not well-informed of the risks and proper handling practices.
Liquid nitrogen is a liquid that has a very low boiling point of -196°C, and is present as a gas at room temperatures. Accidental contact exposure to liquid could cause burns and frostbite, and accidental inhalation or ingestion could cause asphyxiation and airway or gastric perforations due to the extreme cold. Several injuries from ingestion of foods and beverages containing liquid nitrogen have been reported. A 14-year-old experienced a burn on her thumb after handling a liquid nitrogen dessert at a fair. Pollard et al. describe a case of gastric perforation in a teenage girl after consumption of a beverage containing liquid nitrogen; emergency surgery was required to remove the perforated stomach. In Malaysia, a teenager was burned on the palm when he poured some “dragon breath” cookies onto his palm. In Singapore, incidents of burns were reported after consuming “dragon breath” desserts. In India, a man required emergency surgery to remove half of his stomach after consuming beverages containing liquid nitrogen.
As a result of several reports of injuries related to consumption or inhalation of liquid nitrogen and its vapour, the U.S. Food and Drug Administration has issued an advisory to urge consumers to avoid eating, drinking, or handling food products prepared with liquid nitrogen at the point of sale immediately before consumption. Foods that are treated with liquid nitrogen prior to the point of sale, such as frozen desserts, result in complete evaporation of liquid nitrogen. Therefore these foods do not pose a significant risk of injury and are excluded from this advisory.
The BC Centre for Disease Control has developed a series of Notes from the Field documents on the food safety issues that staff have seen in the past. In the document describing the risks and uses of liquid nitrogen in food and beverages, the recommendations include:
- Using food grade nitrogen in food preparation
- No residue of liquid nitrogen should remain in the serving container, and no liquid refill should be provided
- The opening of the serving container should be narrow to prevent consumers from pouring the contents into their hands
- A utensil should be provided to allow only one piece to be picked up at a time
- Clear instructions should be provided to consumers at the point of sale about the dangers and the precautions that must be taken.
For more information about the risks of using liquid nitrogen in food and beverages, please see the BCCDC Notes from the Field document: Safety of novel use of liquid nitrogen and dry ice in the food and beverage industry.