COMBUSTION PRODUCT GAS

CAS: 977054-26-4 PH CONTROL AGENT, PROCESSING AID

Combustion product gas is an FDA‑recognized processing aid used under 21 CFR 173.350 to displace or remove oxygen in specific food processing and packaging contexts. It is generated from the controlled combustion of hydrocarbons and must meet defined purity criteria for safe use.

What It Is

Combustion product gas is a food processing aid permitted under U.S. food additive regulation specifically in 21 CFR 173.350, which governs its manufacture, characteristics, and uses in food processing and packaging. It is defined by its method of production and function rather than a single fixed chemical structure; specifically, the additive is produced by the controlled combustion in air of hydrocarbons such as butane, propane, or natural gas under conditions that are designed to produce a gas mixture suitable for food contact. This gas mixture is used to displace or remove oxygen from food and beverage matrices during processing, storage, or packaging. Because combustion product gas is not a typical single molecule but rather a gas mixture derived from combustion, it does not have an established PubChem CID that can be confidently matched to the specified CAS number, and thus its PubChem identification remains unverified. Its inclusion in 21 CFR 173.350 reflects regulatory recognition of its technological role in food processing under prescribed conditions, not an evaluation of flavor, nutrition, or direct consumption. The key identifiers for combustion product gas include its CAS Number 977054‑26‑4 and its regulatory listing under Section 173.350 of Title 21 of the Code of Federal Regulations. It is sometimes referred to simply by its descriptive name "combustion product gas," indicating its origin from a combustion process rather than a traditional additive with a distinct chemical formula. Because the gas mixture produced may vary depending on feedstock and combustion conditions, its specifications focus on limiting undesirable components like carbon monoxide and controlling optical absorbance as measured by defined analytical procedures to ensure a consistent quality suitable for food contact. Combustion product gas functions primarily as a non‑nutritive processing aid and does not impart flavor or nutritional value. The characterization of combustion product gas is rooted in its physical process origins rather than conventional chemical descriptors. Regulatory language emphasizes manufacturing controls, filtration to remove possible toxic impurities, and specifications for carbon monoxide and ultraviolet absorbance. These specifications ensure that the gas mixture used in food contexts meets safety criteria for displacing oxygen without introducing harmful substances. As such, combustion product gas represents a class of processing aids where function and manufacturing controls are the defining attributes, rather than a specific molecular identity in the way that traditional chemicals or compounds are defined.

How It Is Made

The manufacture of combustion product gas is defined by regulation rather than by a single industrial process outline, but the controlling principle is the careful combustion of simple gaseous hydrocarbons such as butane, propane, or natural gas in air under controlled conditions with appropriate filtration to remove impurities. In practice, the process begins with the selection of a suitable hydrocarbon feedstock, typically a purified gas such as commercial butane or propane or pipeline natural gas, which is introduced into a combustion chamber designed for controlled oxidation. The goal is not complete combustion to carbon dioxide and water, but a controlled partial combustion that yields a gas mixture containing inert and combustion‑derived gases, including carbon dioxide, nitrogen, and small proportions of carbon monoxide. This process is typically monitored and controlled to maintain specific output parameters, including temperature, residence time, and air‑fuel ratio. Crucially, the regulatory framework mandates that the combustion equipment be equipped with an absorption‑type filter capable of removing possible toxic impurities before the gas reaches the food or food contact surface. This filtration stage is intended to capture undesired byproducts or particulates that could arise from incomplete combustion or contaminants in the feedstock. After filtration, the resulting gas mixture is tested for compliance with regulatory criteria, including limits on carbon monoxide content and ultraviolet absorbance in a specified solvent matrix, to verify that it conforms to the standards set out in 21 CFR 173.350. The testing methods employ spectrophotometry to measure absorbance in the ultraviolet range to ensure the gas composition falls within acceptable quality thresholds. This method of production and quality control reflects a broader category of industrial gas processing where safety and purity are central concerns. Because combustion product gas is intended for contact with foods during processing and packaging, its manufacturing environment must be controlled to minimize contamination and ensure that the final gas mixture meets defined criteria for use. The regulatory specifications for its manufacture emphasize both the controlled combustion process and the post‑combustion purification to ensure consistent and safe use as a processing aid. The absence of a well‑defined molecular structure makes the regulatory specification of production and testing conditions central to its identity and safe application.

Why It Is Used In Food

Combustion product gas is used in food processing primarily for its ability to displace or remove oxygen from environments where foods are being processed, stored, or packaged. Oxygen presence can facilitate oxidative changes, spoilage, and the growth of aerobic microorganisms in certain food products. Within the regulatory framework of 21 CFR 173.350, the primary technological function of combustion product gas is to create a controlled atmosphere with reduced oxygen content by physically displacing air in the headspace of packaging or in processing environments. This inerting action can help improve product stability and shelf life for beverages and other foods where oxidative changes are a concern. It is important to note that this role is distinct from active antioxidant additives; combustion product gas does not chemically react with food components to prevent oxidation but instead creates an environment less conducive to oxidative processes. The regulated use of combustion product gas is limited to specific contexts where displacing or removing oxygen is functionally necessary and can be achieved safely under prescribed conditions. The regulation excludes certain products such as fresh meats but includes beverage products and other foods where controlled atmospheres are part of process and quality management. By reducing oxygen levels in processing and packaging, manufacturers can reduce the potential for quality degradation due to oxidation and minimize the risk of spoilage organisms that require oxygen for growth. However, the technology and its application are treated as part of processing control rather than a nutritional or sensory additive, and its use is guided by good manufacturing practices that focus on achieving the intended atmospheric control without introducing harmful byproducts. In contrast to direct food additives that impart flavor, texture, or nutritional benefits, combustion product gas serves a purely technological function that is ancillary to the food itself. Its inclusion in regulatory lists underscores the food safety system’s recognition of controlled atmospheric modification as a valid and potentially beneficial tool in food production when it meets defined safety criteria. Because the gas mixture is designed not to remain in significant amounts in the final packaged product and because its function is wholly related to process control, it exemplifies a class of indirect additives and processing aids that aid in quality maintenance rather than direct contribution to food composition.

Adi Example Calculation

Because combustion product gas is a processing aid and not a direct food additive that remains in the final product at appreciable levels, there is no established acceptable daily intake (ADI) for this substance, and therefore illustrative calculations using an ADI are not applicable. In regulatory practice, ADI values are assigned to food additives that are consumed in measurable quantities and require toxicological evaluation to set safety thresholds. Processing aids like combustion product gas are regulated through specifications that limit undesirable components and by ensuring that residual exposures are negligible. Consequently, attempting an ADI‑based example calculation would not reflect how food safety authorities assess the safety of processing aids that are not intended for consumption, and no numeric ADI is available for such a calculation.

Safety And Health Research

Because combustion product gas is a processing aid rather than a conventional additive that remains in the final food, the safety focus is on ensuring that the gas mixture meets specified quality criteria and does not introduce contaminants or hazardous byproducts into food during processing. Regulatory specifications emphasize limits on certain components such as carbon monoxide and total ultraviolet absorbance as proxies for purity and potential harmful constituents, and these analytical criteria serve to minimize the likelihood that combustion byproducts of concern are present at levels that could pose a risk. The requirement for an absorption‑type filter in the gas production and delivery system reflects a precautionary measure to remove possible toxic impurities from the gas mixture before it reaches food contact surfaces under normal use. These regulatory controls are designed to address potential safety concerns associated with incomplete combustion products or contaminants in the hydrocarbon feedstock. Unlike additives that are intentionally ingested and thus subject to toxicological assessment including acceptable daily intake (ADI) determinations, combustion product gas is used to modify processing environments and is not intended to remain in significant amounts in the final product. As a result, it has not been subject to the same type of toxicological evaluation that would yield established ADI values or comprehensive hazard assessments in the manner typical for direct food additives. Searches of authoritative international food additive safety evaluation databases such as the JECFA database do not readily show a specific chemical evaluation entry linked to the CAS number provided, indicating that formal evaluations of combustion product gas as a distinct additive may not have been published in that context. Therefore, detailed studies on chronic toxicity, genotoxicity, reproductive toxicity, or other health endpoints specific to combustion product gas as a mixture are not available through major international safety evaluation programs. The safety research context for combustion product gas is thus grounded in regulatory quality controls and manufacturing requirements to limit potential exposure to harmful combustion byproducts rather than in direct ingestion studies. By specifying maximum allowable levels of carbon monoxide and controlling the composition through absorbance criteria, regulators aim to mitigate the potential for introducing hazardous substances during processing. However, because it does not have a dedicated toxicological monograph or ADI established by major international bodies like JECFA, definitive statements about specific health effects are not available, and safety assurance relies on compliance with the production and purity specifications set by regulatory authorities such as the U.S. Food and Drug Administration.

Regulatory Status Worldwide

In the United States, combustion product gas is authorized for specific uses under the Federal Food, Drug, and Cosmetic Act and codified in the Code of Federal Regulations at 21 CFR 173.350. This regulatory section specifies the conditions under which the gas mixture may be generated, filtered, and applied to food processing and packaging operations to remove or displace oxygen, including manufacturing controls, purity specifications, and labeling requirements for the equipment providing the gas. The regulation defines both permitted uses and limitations, such as excluding fresh meats from the foods for which combustion product gas use is allowed. Compliance with the carbon monoxide and ultraviolet absorbance specifications is required to ensure safety and consistency of the gas mixture used in food contact operations. Because the regulation is specific to U.S. federal law, it represents a legally binding authorization for the additive’s use in U.S. food processing when the prescribed conditions are met. At the international level, there is no readily available listing of combustion product gas in major global additive inventories such as the FAO/WHO JECFA database as of current publicly accessible datasets, and searches of authoritative JECFA resources do not reveal a specific evaluation or specification entry for this gas mixture. The absence of a clear JECFA entry suggests that it may not have been the subject of a standalone JECFA safety evaluation or that any evaluation has not been linked directly to the CAS number provided. Consequently, global harmonization of regulatory status may vary by jurisdiction, and food regulatory authorities outside the United States may treat the use of combustion product gas according to their own processing aid frameworks or general food contact substance rules. In jurisdictions with additive approval systems similar to the U.S. approach, authorization may be contingent on meeting analogous safety and purity criteria defined by local food law. In summary, the regulatory status of combustion product gas is clearly established in U.S. law under 21 CFR 173.350, which delineates permissible uses, manufacturing requirements, and quality specifications. Outside the U.S., formal listings in international additive databases such as JECFA are not easily identified, and its regulatory acceptance may depend on national food contact substance regulations rather than universal additive listings. Users and regulators must therefore refer to local food safety frameworks to determine permissible applications and compliance requirements in non‑U.S. markets.

Taste And Functional Properties

Combustion product gas, by virtue of being a gas mixture intended for atmosphere control rather than direct ingestion, does not have a taste profile in the way that conventional food ingredients do. It is not included for the purpose of adding flavor, sweetness, or other sensory characteristics, and regulatory descriptions do not ascribe any organoleptic properties to it because its role is not to alter sensory perception. Instead, its functional properties are tied to its physical behavior in displacing oxygen and providing an inert atmosphere in processing or packaging contexts. The gas mixture typically contains a majority of inert components and controlled concentrations of combustion byproducts such as carbon dioxide and minor amounts of carbon monoxide, each of which in the low regulatory‑specified concentrations does not impart a discernible taste when used appropriately for atmosphere displacement. From a functional standpoint, the gas mixture must meet specific physical criteria to be suitable for use in food processing. These include a limit on carbon monoxide content and a specified range for ultraviolet absorbance in isooctane solution, which serves as a proxy for the overall composition and purity of the gas mixture. Meeting these criteria ensures that the gas mixture behaves predictably in its role of displacing oxygen without introducing excessive amounts of reactive or undesirable species. The absence of defined sensory properties reflects its purpose; combustion product gas is not intended to remain in appreciable amounts in the final product or to contribute to flavor or texture. Rather, its effectiveness is measured by its ability to reduce oxygen levels and maintain controlled atmospheres that support product stability. Because gas mixtures used for this purpose are typically flushed through equipment or packaging and not retained in the food at significant levels, they do not contribute to organoleptic profiles. In summary, combustion product gas’s functional properties revolve around its physical role in oxygen displacement and atmospheric modification. It does not have sensory attributes relevant to taste or mouthfeel, and its influence on final product properties is indirect and related to stability rather than sensory enhancement. Its regulatory specifications ensure that the gas mixture used in processing contexts is of sufficient purity and composition to fulfill its technological function without introducing unnecessary risk.

Acceptable Daily Intake Explained

Acceptable daily intake (ADI) is a toxicological concept used by food safety authorities to describe the amount of a substance, typically a food additive, that can be ingested daily over a lifetime without appreciable health risk. It is usually expressed in milligrams of substance per kilogram of body weight per day and is derived from controlled studies where adverse effects are evaluated and safety factors are applied. However, for processing aids like combustion product gas that are not intended to remain in the final food at significant levels, ADI values are generally not established because the focus is on ensuring that residual exposures are negligible and that production and application conditions minimize potential contamination. In the case of combustion product gas, regulatory frameworks such as 21 CFR 173.350 emphasize manufacturing controls and purity specifications rather than ingestion‑based toxicological thresholds. Because the gas is used to displace oxygen and is not a direct additive meant for consumption, safety evaluation centers on controlling undesirable components such as carbon monoxide and potential impurities through defined analytical criteria. This approach reflects the regulatory distinction between substances that are deliberately ingested and those that serve auxiliary roles in processing. Consequently, there is no ADI established by major international bodies like JECFA for combustion product gas, and discussions of ADI are not applicable in the conventional sense. For lay readers, it is important to understand that ADI values are primarily relevant for additives expected to be consumed in foods on a regular basis. In contrast, processing aids that perform technical functions during manufacturing but are not present in significant amounts in the finished product are regulated through manufacturing and use conditions that limit potential residual exposure. In this context, safety assurance is provided by compliance with regulatory criteria for composition and purity rather than by a quantified ADI. Therefore, although the concept of ADI helps explain how direct food additives are evaluated for long‑term consumption, it does not directly apply to combustion product gas as a processing aid whose presence in final foods is minimized and controlled.

Comparison With Similar Additives

Combustion product gas performs a technological role similar to other atmosphere control agents used in food processing, but it differs from many additives that remain in the final product. For example, nitrogen gas is commonly used as an inerting agent in packaging to displace oxygen and protect foods prone to oxidation. Like combustion product gas, nitrogen functions to remove oxygen from headspaces in processing and packaging environments, but nitrogen is a defined single molecule with well‑characterized physical properties and is widely accepted in many jurisdictions for direct contact applications. In contrast, combustion product gas is a combustion‑derived mixture whose composition can vary and is subject to regulatory specifications that control undesirable components. Another related group of substances includes carbon dioxide, which is used both as a processing aid and as a component in modified atmosphere packaging. Carbon dioxide can inhibit microbial growth and is used in packaging of fresh produce and other foods, often in combination with nitrogen. While carbon dioxide can have direct sensory effects at higher concentrations, its use as an atmosphere control agent highlights how gases can serve multiple roles depending on context. Combustion product gas, on the other hand, is not used for sensory or preservation functions directly but strictly for oxygen displacement under prescribed conditions. Oxygen scavengers such as iron‑based sachets or chemical absorbers represent a different class of oxygen removal technologies used in packaging. These typically involve materials that react with oxygen to chemically bind it and are used to maintain low oxygen levels in packaged foods susceptible to oxidation. Unlike combustion product gas, which physically displaces oxygen, chemical scavengers actively remove oxygen through chemical reactions. Each approach has its own technological context and regulatory considerations, with combustion product gas situated within the regulatory framework for processing aids and atmosphere control in U.S. law. By comparing these technologies, it becomes clear that combustion product gas’s role is specific to controlled combustion gas mixtures used to displace oxygen, rather than a broader class of inert gases or reactive scavengers used to maintain package atmospheres.

Common Food Applications Narrative

Combustion product gas is most often encountered in industrial and commercial food processing settings where control of the processing environment is critical to product quality and stability. Because its principal role is to displace oxygen in environments surrounding food products during processing or packaging, it is used in situations where controlled atmospheres can help maintain product attributes and extend shelf life. For example, in beverage production, oxygen removal can be important during bottling or canning processes to limit oxidative changes that might affect color, aroma, or shelf life. Similarly, certain packaged foods that are sensitive to oxidation may be processed in equipment where combustion product gas flows through the headspace to create an atmosphere with reduced oxygen before final sealing. The use of combustion product gas is defined by regulation and confined to specific functions and food categories. It is not used in consumer kitchens or home food preparation but rather in manufacturing operations where packaging lines and processing chambers can be equipped to introduce the gas under controlled conditions. Beverage products like juices, soft drinks, and other non‑meat foods can be treated with combustion product gas to remove oxygen prior to sealing, which can help preserve quality attributes that might otherwise degrade in the presence of oxygen. Because the regulation excludes fresh meats from its allowable uses, its application in meat products is limited, and processors rely on other approved atmosphere control methods for such foods. In commercial beverages and other packaged foods, the focus is on creating an appropriate processing atmosphere rather than imparting direct changes to the finished product’s composition. Combustion product gas is not present as a significant residual in the final product but is rather a tool used during manufacturing to ensure that packaging environments are optimized. The widespread adoption of controlled atmosphere techniques across various segments of the food industry underscores the importance of oxygen management in ensuring product stability and quality, and combustion product gas represents one regulatory‑recognized means of achieving this when used in compliance with prescribed conditions. Its use is typical in large‑scale production facilities where equipment can accommodate the gas introduction and monitoring required to meet 21 CFR 173.350 specifications, and it is part of the suite of technologies employed by food processors seeking to manage oxygen levels without resorting to direct additive incorporation into the food itself.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 173.350

EFSA

  • Notes: EFSA evaluation not identified in available authoritative additive databases

JECFA

  • Notes: No specific JECFA evaluation entry identified for this CAS number

Sources

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