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September 18, 2018

What are the Perils of Liquid Nitrogen in Food?

The Power To Take Your Breath Away – and So Much More!

liquid nitrogen food

What’s cold enough to burn your insides and ephemeral enough transform you into a fire-breathing dragon? Liquid nitrogen, the new darling of festival and fair food, turns out to be an additive that we need to treat very carefully. With the new craze for Dragon’s Breath cereals sweeping the carnival-going community, how concerned should we be about our children’s health when it comes to chemically-enhanced snacks? Read on to learn more…

Ever heard of Dragon’s Breath…?

As the heat of summer segues slowly into the mellow fruitfulness of fall our thoughts turn to festivals and fairs, a staple of autumn and one of life’s mile markers of the true end of summer. And who doesn’t love fairs, with all of the innocent activities of our childhoods – the roller coasters, taffy apples, and carnival barkers vying for our attention, not to mention our dollars. And another great excitement about these fairs as they trundle into town is the array of new food temptations and novelties they bring with them. We’re talking about items never seen anywhere else – delicacies such as spicy peanut butter and jelly cheeseburgers, deep-fried Oreos, or pickle dogs that all just beg to be consumed on a trip to the fair because…if not now then when? According to Jessica Wakeman, a writer for CNN Travel, we love to sample ‘offbeat’ fair victuals, a fact that keeps vendors ‘trying to outdo each other for the weirdest food.’(1) But if you thought the height of cool was a root-beer float or the iconic sno-cone, think again. There’s something altogether frostier that’s topping the list of ‘cool foods’ at fairs today and unfortunately it is not without dangers. Ever heard of Dragon’s Breath…?

…imagination, a certain culinary flair, and the application of science – the use of liquid nitrogen, to be exact.

Imagine, if you will, popping a food treat into your mouth and exhaling clouds of pure white smoke. Or, if festival food is not to your taste, conjure up the image of a classic vodka martini, fog roiling out of the glass and snaking its way along the polished bar top. Or perhaps your preference is for a creamy frozen dessert at a Michelin-starred restaurant, icy crystals of raw frozen honey glittering atop a smoking cold dish. All of these foodie delights – from annual festivals to once-in-a-lifetime culinary extravaganzas – are possible only with a good deal of imagination, a certain culinary flair, and the application of science – the use of liquid nitrogen, to be exact.

Liquid nitrogen – LN or LN2 – is the fractionated distillation of liquid air and, with the ability to freeze living tissue on contact, is a leading cryogenic fluid. Beloved of school science experiments for its ability to billow delightful clouds of white ‘smoke,’ LN is a colorless, clear liquid with a broad spectrum of purposes, from use as a coolant in CCD cameras in astronomy or overclocked computer processors, to hypoxic fire prevention systems, to promession – the freeze drying of human remains for disposal. When stored correctly, LN can be transported relatively easily in a vacuum flask and, given appropriate insulation, maintains its low temperature, which makes it a useful tool in both in the kitchen and the laboratory alike. But it is specifically the innovative ways in which it is used in food that has us looking closely at this frosty ingredient.

…Hector Blumenthal of ‘The Fat Duck,’ one of only five 3-Michelin-starred restaurants in the United Kingdom, uses LN to create his feted bacon and egg ice cream.

First liquefied in 1883 by physicists Zygmund Wróblewski and Karol Olszewski of the Jagiellonian University in Krakow, Poland, liquid nitrogen is all about temperature. The speed with which it freezes ingredients allows very tiny ice crystals to form in dishes where creaminess and an ultra-smooth consistency is required. For instance, in an inarguably innovative but subjectively unappetizing dish, Hector Blumenthal of ‘The Fat Duck,’ one of only five 3-Michelin-starred restaurants in the United Kingdom, uses LN to create his feted bacon and egg ice cream. And Blumenthal is not alone in his creativity. Spanish chef Quique Dacosta also uses LN to create a solidified Parmesan foam that he dusts across quite ordinary mushrooms in order to emulate the taste and experience of those foodie favorites, the wild truffle. From ‘cryopoaching’ oils to ‘cryoshattering’ meat or cheese, LN flash-freezes foods without disrupting the cellular structure of the materials involved. And once that berry is cyro-frozen, it can be crushed into a powder to dust a morsel of moist chocolate brownie or float on the top of a refreshing libation.

And, in essence, all that’s needed to create these gastronomic curiosities are a few basic tools such as safety canisters, protective eyewear, and gloves. And, of course, a solid working knowledge of how the gas reacts to changes in pressure and its effects on the human body when ingested, which is perhaps the key to our examination of the Dragons Breath phenomenon today. For instance, when using the liquid it is critical to ensure proper ventilation to maintain flasks of LN safely. If the ventilated container becomes sealed, pressure can rise and lead potentially to an explosion. Why? Because when liquid nitrogen warms it expands into a gas that is 700 times the volume of the liquid form. In a sealed unit, this expansion clearly cannot occur safely. Furthermore, if a volume of the liquid is released as a gas into an unventilated room, it can create an hypoxic environment that silently, without odor or color, risks suffocating anyone unfortunate enough to be working therein.

And there is a second difficulty in working with the liquid: burns. When the frozen vapor comes into contact with the skin it warms immediately, turning from liquid to gas and evaporating into the air. Assuming this contact is sufficiently brief, there is little danger of injury but, if the contact is prolonged, the liquid, which maintained at 77Kelvin or -321.07ºF has the ability to cause damage not only to the skin but also to the underlying tissues. And if it pools on a surface, the results can be life-threatening. Take, for example, when ingested in a shot of alcohol…

According to a report in BBC’s Newsbeat, a British woman suffered a perforated stomach from consuming a cocktail laced with LN.(2) Following the ingestion of the Nitro-Jagermeister shot as a birthday celebration, Gaby Scanlon was rushed to hospital where surgeons were forced to remove her entire stomach which had ruptured after the beverage blew a hole in it. The intervention ultimately saved her life but left her with an esophagus permanently connected directly to her small bowel and, since the incident, she remains unable to eat comfortably, lacks satiety cues, and subsists on a highly restrictive diet.

But how did this occur? In addition to potentially burning the skin and underlying tissues, when LN comes into contact with the warmth of the stomach it expands rapidly releasing a large volume of air. This process is termed the Leidenfrost effect and, when it occurs in a confined area such as within the human GI tract, it can quickly result in organ perforation requiring emergency treatment. So, given the abundance of documentation relating to the hazards of using liquid nitrogen for food and beverages, it seems incongruous that we are starting to adopt this craze when our British cousins across ‘The Pond’ have been aware of the dangers of liquid nitrogen in food and beverages since at least 2012. Perhaps we have better regulation in terms of governmental oversight? Let’s take a look…

In the United Kingdom, the Food Standards Agency (FSA) has publicly issued an alert that while liquid nitrogen ‘was not a toxic substance, it was unsafe to drink and eat as the human body was unable to cope with such a cold internal temperature.’(3) Moreover Dr. John Ashby, director of public health for Cumbria (the area in which Gaby Scalon resides), is on record as stating that bars should not ‘be playing with chemistry,’ advocating enhanced regulation and questioning why ‘more MPs were not challenging the drinks industry.’(4) With that said, the substance is already subject to the ‘Health and Safety at Work etc. Act’ of 1974, the ‘Control of Substances Hazardous to Health Regulations’ of 2005, and the ‘Food Safety Act’ of 1990. This triumvirate legislation governs how staff in food establishments use the substance, how it should be stored and ventilated, and the responsibilities a bar or restaurant would have for ensuring that any victuals using the liquid remain ‘safe and fit for human consumption.’(5)

But the standard of regulation and scrutiny in place for established restaurants – whether Michelin-starred or otherwise – is radically different from that which is in situ for temporary food vendors such as those encountered here at home at seasonal fairs and festivals.

…transient food vendors are realistically unlikely to have complete Hazard and Critical Control Points protocols (HACCPs) in hand…

So let’s take a look at food safety issues with treats you might be tempted to enjoy at the fairground. Although seasonal fairs tend to be especially popular in the fall when the weather is a little cooler, temperatures in some areas remain high enough for bacterial contamination to remain a problem. Indeed, according to the United States Department of Agriculture (USDA) although foodborne illnesses are highest in the summer the humidity of fall also encourages them.(6) And using flash freezing with LN is not going to remove the issue of spoilage of contamination completely because, although the end product is frozen, the ingredients need to be adequately refrigerated prior to purchase. Suppose a vendor is offering a LN ice-cream cone – how do we ensure that the cream and other dairy components used in crafting that treat have been correctly stored and handled? Given that the county or state will usually have limited resources for regulating inspections, and equally that transient food vendors are realistically unlikely to have complete Hazard and Critical Control Points protocols (HACCPs) in hand, it’s easy to imagine that the production, sale, and consumption of these items is probably less regulated than we’d like to believe. So, in the face of a bevy of potential issues, how do we protect ourselves and our loved ones from bringing home more than we’d bargained for on our weekend at the fair?

…food poisoning or injury is definitely not what you want to remember when you think back to that ‘fun day’ spent at the county fair.

The Centers for Disease Control and Prevention (CDC) recommends above all ensuring that the vendor has a current valid license to sell food. With that in the bag, it’s time to check that the employees are wearing gloves or using tongs when handling food, and that all necessary equipment – refrigeration and cleaning stations – are in place and being actively used. But let’s broaden the scope of our inquiry: what about restroom facilities for the food handlers? If access to hygienic facilities is not readily available, it’s easy to imagine how quickly contamination can occur. Which, of course, is why we see outbreaks of E. coli infections clustering around county fairs such as the one in Mesa County, CO, or Washington County in Oregon.(7) And then there’s the problem of food sitting out in the sun all day. Perishable foods that are nonetheless popular at fairs and festivals include innocuous-seeming dishes such as potato salad and leaf salads as side dishes but, despite their appeal as comfort food or a healthy alternative to the deep-fried Oreo stand, the salad shack may not be the best choice for contamination-free snacks. No, that warmed over mayonnaise will probably not lead to you losing your entire stomach, but it could result in you becoming a CDC statistic – like the 48 million people who suffer food poisoning annually, of whom 128,000 are hospitalized, and 3000 die.(8) And as much as carnival or fair foods are tempting for their novelty – whether it is the Dragon’s Breath treats with the power to literally take your breath away or the humble hot dog whose bacterial load can empty your stomach faster than the average roller coaster – food poisoning or injury is definitely not what you want to remember when you think back to that ‘fun day’ spent at the county fair.

Breathing like a mythical creature – would you risk it? Are you concerned about carnival and fair food regulation? We’d love to know your thoughts.

References:

  1. https://www.cnn.com/travel/article/fair-food-america/index.html
  2. https://www.bbc.com/news/uk-england-lancashire-34269286
  3. https://www.theguardian.com/uk/2012/oct/12/mp-ban-liquid-nitrogen-cocktails
  4. ibid
  5. https://www.preston.gov.uk/businesses/health-and-safety/occupational-health/coshh/liquid-nitrogen/
  6. https://www.scpr.org/blogs/southla/2013/04/09/13227/fairs-festivals-contribute-to-food-poisoning-spike/
  7. https://foodpoisoningbulletin.com/tag/county-fair/
  8. https://www.scpr.org/blogs/southla/2013/04/09/13227/fairs-festivals-contribute-to-food-poisoning-spike/

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