Gases used in refrigeration including carbon dioxide, nitrogen, oxygen, helium, and ammonia play an important role in frozen food and food storage applications. Whether the gases are used to maintain quality, preservation, freezing, or extend shelf life, they have created numerous benefits for consumers.
When it comes to frozen food storage and preservation, the use of gas is critical. However, gas safety is just as critical for those working around these gases.
The Role of Gases in the Frozen Food Storage Applications
The technology of using compressed gases for refrigeration began in the late 19th century. In the early 1900's home refrigerators using small gas compressors were developed. However, it was not until World War II when the military required large quantities of food to be transported and stored efficiently. “An army marches on its stomach” is often attributed to French Emperor Napoleon Bonaparte. In addition to dried and canned foods, soldiers wanted fresh food from home. This helped start the future industrial use of gases for food storage and preservation.
As the need for all gases in industry increased, the application of gases for quick freezing and packaging at an industrial scale became a crucial segment. Whether gas was used in maintaining the quality, safety, or shelf life of food, it quickly became essential in the field. With the use of gases like carbon dioxide, nitrogen, oxygen, helium, and ammonia, the frozen food industry has been able to further advance food quality and create benefits for consumers.
Gases Used in Frozen Food Applications
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Liquid Nitrogen (LN2): Liquid nitrogen is often used for quick freezing of food products known as “cryogenic freezing”. It has an extremely low boiling
point of -196° degrees Celsius (-321° degrees Fahrenheit), making it
highly effective for rapidly reducing the temperature of food. - Nitrogen (N2): Nitrogen is used in several ways in the frozen food industry, for inert gas blanketing to displace oxygen and create a protective atmosphere in food packaging and to prevent oxidation. With the use of nitrogen, food manufacturers can preserve and maintain food quality as well as increase the shelf life of fresh food.
- Carbon Dioxide (CO2): Carbon dioxide can be used as a refrigerant in modified atmosphere packaging (MAP) to control the gas composition or to extend the shelf life and preserve product quality. It can also be used to carbonate frozen beverages and add flavor to carbonated products. Further, CO2 is also used as dry ice for food refrigeration in transit and short-term storage.
- Oxygen (O2): While oxygen is not used directly in frozen food processing, its exclusion through modified atmosphere packaging or inert gas blanketing helps prevent oxidation and maintains the quality of frozen products.
- Helium (He): Although less common, helium can be used in cryogenic cooling and freezing applications. This is in part due to its advantage of being extremely cold and non-reactive, making it suitable for specific freezing processes. It's recent scarcity concerns have limited its use in food production.
- Ammonia (NH3): These gases are used in industrial refrigeration systems for maintaining low temperatures in storage and transportation of frozen food products. This gas is also highly toxic and flammable, making it a hazardous cold storage gas. Ammonia if not properly monitored, can lead to prolonged chronic exposure and lead to several irreversible effects.
Overall, the use of gas in the industry serves a variety of purposes, each of which holds their respected function in the processing, preservation, chilling, and packaging of food. These gases paired across application help to maintain the freshness, texture, flavor, and nutritional value of the food, as well as ensure safety for its consumers. Further, the frozen food industry needs preservation and there is no other element than gas that can aid in preserving temperatures below 0°C which is critical. In the absence of gas, this industry would result in slower freezing, likelihood of food borne illnesses, and degradation of quality and texture.
Gas plays a critical role in food production that we know directly impacts both producers, manufacturers, and consumers in the field.
Which Frozen Food Storage Applications use Gas?
Food production, preservation, and flash freezing involve various industries and sectors, as the process is applied to a wide range of food products. When it comes to industry segments, they all use gases respectively, but how they use that gas ranges depending on the application and the desired outcome of the product. Below we highlight some of the industries in food production that utilize preservation, cold storage, freezing, and above all else - gas.
Modified Atmosphere Packaging
Modified atmospheric conditions are now commonplace in the packaging, storage, and transport of all kinds of food products, from fresh to frozen produce. High carbon dioxide and reduced oxygen levels can also be beneficial for killing insect species of microorganisms that would otherwise grow on and spoil the food as it was stored.
High nitrogen concentrations can additionally be used as a humidity control for dried foods as it can help preserve food quality while extending food lifetime. By using gas mixtures to replace insecticides and the addition of preservatives such as nitrites to meats, modified atmospheric packaging offers a versatile way to preserve foods without the need to add additional chemicals or processing stages.
Beverage Industry
The carbonation of beverages, such as carbonated soft drinks, sparkling water, and beer, involve the use of carbon dioxide (CO2) gas to create effervescence. In addition, nitrogen can also be used to give frothy texture to certain beverages, such as stout beer or nitro coffee. Blanketing with gases, usually nitrogen, can be used in addition to create a protective atmosphere above the liquid in storage tanks.
Baking and Pastry Production
In the baking and pastry industry, gases are used for leavening, where carbon dioxide is produced to help dough rise, resulting in baked goods like bread, cakes, and pastries with a light, airy texture. When fillings or toppings, such as those in quiches, expand and set during baking, gas production can also play a role in the desired texture or appearance. Nitrogen can additionally be used as a key cryogenic agent in cooling, chilling, and food freezing.
Dairy Industry
The dairy industry uses gases in various applications, including the injection of nitrogen gas into milk to remove oxygen, extend shelf life, and preserve the flavor and nutritional quality. Gases may also be used to control the temperature and humidity in dairy storage facilities, ensuring that dairy products are stored in the appropriate conditions to maintain their quality and safety.
Freezing and Cryogenic Cooling
Gases such as liquid nitrogen (LN2) are used for rapid freezing and cryogenic cooling in various food industries to preserve the quality of products during the freezing process. This process involves lowering the temperatures of food to a point where most of the water in the food turns to ice. Freezing also prevents microbial growth and enzymatic activity that can spoil the food. There are different methods of freezing, such as air-blast freezing, contact freezing, and cryogenic freezing.
Animal Processing and Euthanasia
This segment relates to the euthanasia of livestock and animal processing. The choice of gas and method depends on the situation and specific needs of the species involved. Typically, carbon dioxide and nitrogen are used commonly to stun animals before slaughter. This can induce an unconsciousness and alleviate pain and distress often used for poultry production.
Food Distribution and Transportation
This is the process of transporting and delivering frozen food products to consumers, retailers, or end users. Distribution often requires maintaining the cold chain, which is a system of refrigerated storage and transportation that ensures the food remains frozen and safe throughout its journey. Nitrogen is most often used to create an inert atmosphere during food distribution that prevents oxidation and microbial growth.
Canning and Food Preservation
Gases, such as nitrogen, can be used to create a protective atmosphere in canned food products to prevent oxidation and maintain product quality. In the canning process, inert gases like nitrogen are used to displace oxygen within the cans before sealing. This inert gas blanket prevents the oxidation of the food, which can lead to spoilage, off-flavors, and color changes.
Frozen Food Compressed Gas Hazards
Within food production and manufacturing there are several sub-industries we previously touched on, all that use compressed gases as an essential component of their day-to-day process. The use of these compressed gases can present various hazards, and it’s essential to manage these risks by use of gas safety monitoring to ensure the safety of both workers and consumers.
Common hazards associated when using compressed gases include pressure, asphyxiation, convulsions, toxicity and inadequate ventilation. Because gases are stored at such high pressures, if not properly handled, they can lead to ruptured containers, leaks, or even explosions.
Workers in the food production, preservation, and chilling industries may often be at risk of injury from flying debris or the force of the gas release. In addition, some gases used in food production, like nitrogen and carbon dioxide, can displace oxygen in confined spaces. This can lead to inadequate ventilation, oxygen deficiency, or pose a risk of asphyxiation to workers and those near gas hazard points.
For some gases that react with food products or other substances in the production environment, they too can also lead to potential negative health effects or chemical reactions due to hazardous byproducts. This can further affect food quality, product, and overall safety for the consumer and end user. To mitigate these hazards, it is critical to follow strict safety procedures when dealing with compressed gases and be able to mitigate hazards before they occur.
Below we highlight the main hazard locations you should know when working near or around dangerous compressed gases in the field.
- Cold Storage Areas: Cryogenic gases like liquid nitrogen are used for rapid cooling and freezing of food products. These gases can be extremely cold and can cause frostbite or cryogenic burns if they meet skin or eyes. These areas can present fire safety concerns. For instance, a fire broke out at Buffalo Farms Freezer and Cold Storage, a fruit-packing and storage warehouse in Hammonton, New Jersey, which reportedly started from hot work activities taking place at the facility.
- Post-Lethality Region: After thermal processing, food products are typically exposed to the environment prior to freezing in an area commonly referred to as the post-lethality region. This area is a critical component of Listeria monocytogenes control.
- Gas Supply and Storage Areas: The area where compressed gas cylinders are stored and maintained can be dangerous if not managed properly. Leaking cylinders, improper storage, and mishandling pose risks to workers in this area.
- Food Production and Packaging Line: The use of compressed gases for modified atmosphere packaging is common. These gases can be used inside the food packaging yet when altered, can carry risks associated with the handling and storage of these gases. Gas leaks or incorrect gas mixtures can affect product quality and safety.
- Laboratories and Quality Control: Food production facilities often have laboratories for quality control and testing. Some of these labs may use compressed gases for various analytical processes, and potential hazards must be managed in these areas.
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Food Transportation and Handling: The transport and handling of
compressed gas cylinders to and from various areas in a food production facility poses risks if not done carefully. Falling cylinders can cause injuries, leaks, and damage.
To mitigate risks in these areas, food production facilities should implement safety measures, including proper training, the use of appropriate gas safety monitoring, personal protective gear, regular inspections, and overall adherence to safety standards. Additionally, facilities should conduct risk assessments and emergency response planning to address potential compressed gas hazards effectively.
Gas Safety in Food Storage
For those entering cold rooms or walk-in freezers, these areas are an integral part of the food production industry. Yet, typical refrigerant gases are present which include but are not limited to carbon dioxide, ammonia, nitrogen, and hydrocarbons such as propane, isobutane, and propylene. Thus, a versatile range of gas safety detection solutions are required.
For example, there have been numerous accidents involving gas leaks that have been reported worldwide, hospitalizing hundreds, and even resulting in fatalities.
Typical gas leak accidents involve system wear or failure of components, lack of preventative maintenance guidelines, and lack of gas detection solutions.
For frozen food production and preservation, only a gas safety monitor or a analyzer can help mitigate hazards, maintain preservation of product and ensure employee safety for your staff and establishment.
Because gases like CO2 are so dangerous and can’t be detected by the human eye, the National Institute for Occupational Health and Safety (NIOSH) has put standards in place. These standards state that CO2 levels of 40,000ppm (4%) are immediately dangerous to life and health within 10-hour workplace exposure limits.
In fact, due to such severe incidents around the globe, the Occupational Safety and Health Administration (OSHA) has put together a list of standards for businesses to abide by when entering confined or potentially oxygen deficient spaces.
These standards state, “For any employee who must enter a confined space or potentially oxygen deficient space may require a low oxygen deficiency alarm, a respirator, or personal protection equipment." OSHA also defines an oxygen deficient atmosphere, as any atmosphere where less than 19.5% oxygen is found by volume. At lower levels, severe negative health effects can occur as follows:
It’s a popular myth in the industry that monitoring for low oxygen levels will give an appropriate carbon dioxide reading. The reality, however, is that carbon dioxide can escalate to danger before any oxygen sensor would ever alarm, because CO2 settles first at the floor and oxygen sensors are most typically mounted at eye level.
Like NIOSH, OSHA also sets a current standard for those working, using, or storing hazardous carbon dioxide gases. The current OSHA standard is 5000 ppm as an 8-hour time weighted average (TWA) concentration. Concentrations of 10 (100,000 ppm) or more can further produce unconsciousness, seizures, and even fatality.
Normal levels of CO2 in fresh air are approximately 400 ppm (parts per million) or 0.04% CO2 in air by volume. The table below shows the effects of increased CO2 levels in an enclosed space as a percentage of air by volume.
Read the complete list of OSHA, NIOSH and other CO2 standards here.
Overall, when it comes to hazardous gases like nitrogen, oxygen, ammonia, and carbon dioxide; extreme exposure can be fatal. If a canister or supply line begins to leak, gas will soon enter the entire facility or if a fitting is loose, this can mean severe danger for anyone in the establishment. When this happens, hazardous gas can displace the air and since no one can tell of the leak, only a real-time gas safety monitor can indicate that danger is near.
These gas leaks, as unfortunate as they are, are common in enclosed spaces such as food production rooms, freezers, processing lines, and chillers. The easiest way to protect employees’ safety is by installing a gas safety monitor to track gas levels, sound an alarm, and warn all employees near potential leak points. These safety monitors operate by tracking gas concentrations in real-time, sounding an alarm for high concentrations, and ensuring peace of mind for your staff, employees, and establishment.
Gas Safety Monitors
Gas detection monitoring is a critical piece of safety for food production, preservation, and chilling industry professionals. However, for every application, there are several core factors that individuals should know specifically when choosing a device. If you need to monitor the lack of oxygen or nitrogen in space, look for an oxygen deficiency safety alarm.
If you need to measure high concentrations of carbon dioxide, look for a carbon dioxide safety alarm. The issue isn't so much finding the right gas detection device but choosing the right device from the many choices you have.
Gas detectors typically come in two options – fixed or portable gas detection. When we look at fixed or wall-mounted gas detectors as a category, these devices are most identified for general installation in a commercial facility. They detect leaks as well as provide an early warning of higher than normal gas concentration levels.
Mounted in one location, these devices are permanent fixtures used when constant gas detection is required. Fixed gas detection systems also are typically configured using relays and specified alarm settings to meet code requirements, or OSHA, NIOSH, and CGA standards. These settings ensure that fixed gas detectors respond quickly and accurately to atmospheric hazards. In addition, relays provide several functionalities that can be vital to saving lives, including:
- Triggering an exhaust fan
- Opening ventilation
- Triggering valves that shut-off gas supply
- Notifying emergency services by wiring to a fire control panel
Alternatively, handheld or portable gas detectors are used when detection is temporary, when fixed detection is not an option, or for personal gas safety and protection.
Portable gas detectors are also used in confined space entries. For instance, individuals that are working in and out of cold storage facilities or who transport dry ice find these devices critical and useful for their day-to-day operation.
Need more assistance to ensure you are choosing the right gas detection safety monitor for your industry or location? Contact us today.
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