Carbon dioxide

Carbon dioxide (CO₂) is a colourless, odourless gas that serves multiple functions in food production. As a carbonation agent, it creates the characteristic effervescence of sparkling water, carbonated soft drinks, beer, and sparkling wine. As a packaging gas (modified atmosphere packaging), it inhibits the growth of aerobic bacteria and moulds, significantly extending the shelf life of fresh meat, cheese, baked goods, and salads without any chemical residue. It is also used as a propellant in aerosol food products.

No formal JECFA ADI has been assigned — carbon dioxide is a normal product of human metabolism, exhaled with every breath and produced continuously by cellular respiration. There is no toxicological concern at any exposure level achievable through food consumption. The small amount dissolved in carbonated beverages is rapidly released during digestion and absorbed into the bloodstream as normal metabolic CO₂.

Carbon dioxide is universally approved in the EU, US (GRAS), UK, Australia, Japan, and Vietnam. Food-grade CO₂ must meet purity specifications to exclude contaminants such as benzene or methanol. It is one of the most important and safest food processing aids available, and its presence in a product is not cause for any health concern. The perception that carbonated beverages cause "bloating" is attributable to the gas release during digestion, which is a physical effect rather than a toxicological one.