Recently a young man at a New Delhi bar consumed a cocktail from a glass chilled with Liquid Nitrogen. Immediately he began to feel ill and was rushed to hospital. When the doctors prepared him for surgery they saw that his stomach had been perforated so badly that half of it had to be removed. The incident has sent shock waves across the food and beverage industry. There are a number of trendy bars and restaurants that chill cocktail glasses with Liquid Nitrogen or use it in foods for its dramatic food experience. When liquid is added to the glass it begins to smoke and emits a vapour which makes foods and beverages interesting. The chefs and bartenders using Liquid Nitrogen are usually well trained. They even make it a point to caution the customers not to drink the cocktail or eat foods until the smoke from the Liquid Nitrogen is completely vaporised.
While Liquid Nitrogen is safe to use in food or beverages it should not be consumed. The main point is that liquid nitrogen must be fully evaporated from the food or drink before serving. Drinking the liquid without full vaporisation means the customer will ingest it. Ingesting is dangerous because it causes severe damage to the tissues in the mouth, oesophagus, and stomach. As Liquid Nitrogen vaporizes it turns into nitrogen gas which causes pressure in the body tissues and can cause holes in the tissues. Since it is extremely cold it can also cause severe frostbite. But while liquid nitrogen is commonly used by trained chefs, it can be extremely dangerous or deadly if not handled properly.
Liquid Nitrogen in food industry
Liquid Nitrogen is used in food industry for the following
- Freezing and chilling because it is more cost effective when compared to traditional methods. It can chill large quantities of food in just a few minutes unlike traditional chilling and freezing methods which take hours
- Freezing meats, fish, poultry, dairy and bakery products besides pasta, microwavable meals, fruit and vegetables.
- Maintaining the freshness of packaged food products. It also delays rancidity of fatty food products and prevents oxidative damage. Traditional freezing can cause large crystal formations on food products but Liquid Nitrogen prevents crystal formation and so there is no cell damage or dehydration. The fast freezing with Liquid Nitrogen creates very tiny ice crystals which seal in the moisture in the food product and so maintain better quality.
- Fresh fruit and convenience foods do not require freezing only chilling and so they are chilled cryogenically using Liquid Nitrogen.
- Liquid Nitrogen has become popular in the retail food and beverage industry for the preparation of novelty ice creams and cocktails also.
- Liquid Nitrogen is also used in industrial packaging like Modified Atmosphere Packaging (MAP) and Controlled Atmosphere Packaging (CAP). Liquid Nitrogen is injected into the packaging which rapidly expands displacing air in the container. This can be used to lengthen product life or to pressurize the container.
Use of Nitrogen as per FSS Act, Rules & Regulations
‘Nitrogen’ as an additive bearing INS no. 941 allowed to be used in food products, through GMP tables given under Food Safety and Standards (Food Products Standards and Food Additives) Regulations, 2011 and the latest amendment on September 5, 2016.
Nitrogen (INS 941) has two technical functions (as given under regulations) – Packing gas and Freezant, so it is allowed to be used in some of the categories of food products as per Good Manufacturing Practice (GMP). The categories of food products have also been mentioned where this additive can be used along with its keen purpose. GMP means; a minimum required quantity of an additive to give a desired effect for its intended use.
FSSAI has permitted the use of nitrogen (INS 941) in the following food categories:
- Fermented milks (plain) heat treated after fermentation – Nitrogen (INS 941) to be used as packing gas only, RML as per GMP.
- Renneted milk (plain) – Nitrogen (INS 941) can be used, RML as per GMP.
- Sterilized and UHT creams, whipping and whipped creams, and reduced fat creams (plain) – Nitrogen (INS 941) to be used as packing gas only, RML as per GMP.
- Peeled or cut fresh fruits – Nitrogen (INS 941) to be used as packing gas only, RML as per GMP.
- Coffee, coffee /coffee substitutes, tea, herbal infusions, and other hot cereal and grain beverages, excluding cocoa – Nitrogen (INS 941) to be used as packing gas only RML as per GMP. It can also be used in the ready-to-drink products and pre-mixes for ready-to-drink products only.
- Fruit juices (fruit juices for industrial use, thermally processed fruits juices) – Nitrogen (INS 941) can be used, RML as per GMP.
- Vegetable juices(vegetable juices for industrial use, thermally processed vegetable juices, thermally processed tomato juice – Nitrogen (INS 941) can be used, RML as per GMP.
- Concentrates of fruit juices (concentrated fruit juices for industrial use) – Nitrogen (INS 941) can be used, RML as per GMP.
- Concentrates of vegetable juices (concentrated vegetable Juices for industrial use) – Nitrogen (INS 941) can be used, RML as per GMP.
The food category “Aromatized alcoholic beverages” indirectly comes under the category of food products where Nitrogen (INS 941) can be used as per GMP as though specifically it is not mentioned but since it does not come under the category of food products for which GMP Table shall not apply. FSSAI has not specifically mentioned “Liquid Nitrogen” anywhere in the regulations.
About Liquid Nitrogen
Liquid Nitrogen is actually nitrogen in a liquid state which has extremely low temperature (-196°C). At room temperature it expands rapidly into nitrogen gas. Just one litre of Liquid Nitrogen produces 700 litres of nitrogen gas. Liquid nitrogen is completely inert, colourless, tasteless, odourless, and has no adverse environmental effects. It is also called a cryogenic liquid and is commonly used in a variety of cooling applications such as food freezing, biological sample preservation, metal treatment and lesion removal (cryotherapy).
Precautions when using Liquid Nitrogen
- Liquid Nitrogen must be used only in areas that are properly ventilated. Since liquid nitrogen has no odour or colour its presence cannot be detected easily.
- The areas where Liquid Nitrogen is stored must have an oxygen monitoring system as leaking nitrogen can displace oxygen. When nitrogen becomes loose in the atmosphere, it creates a state of oxygen deficiency leading to suffocation. The oxygen monitoring system takes regular readings of the oxygen in the environment and if there is a deficiency workers have enough time to evacuate the premises.
- Personnel handling Liquid Nitrogen must wear protective clothing including thick gloves like, closed tough shoes not canvas ones as those can absorb nitrogen gas. If workers accidentally get liquid nitrogen on their skin while manufacturing they will suffer severe burns.
- Use only cryogenic storage tank or liquid cylinder for storing Liquid Nitrogen
- When transferring Liquid Nitrogen prevent splashing and pressure build up
- All personnel working with Liquid Nitrogen must be fully trained about handling it, using protective gear, know how to calibrate oxygen monitoring equipment and handle emergencies.
- An emergency plan must be in place including first aid measures.
** RML – Recommended Maximum Level