What gas or chemical do supermarkets and butchers use to keep meat looking fresh longer?

The gas commonly used to keep meat looking fresh longer is carbon monoxide (CO).

Carbon monoxide is a colorless, odorless, and toxic gas that binds to the myoglobin in meat, forming a bright red compound called carboxymyoglobin. This reaction slows down the deterioration of the meat and preserves its bright red color, making it appear fresh.

The use of carbon monoxide to preserve meat is a controversial practice. While some argue that it is safe and effective, others raise concerns about the potential health risks associated with CO exposure. Carbon monoxide is known to be toxic to humans and can cause various health problems, including headaches, dizziness, nausea, and even death in high concentrations.

Supermarkets and butchers are required to follow strict guidelines and regulations regarding the use of carbon monoxide and must ensure that the levels of CO in their display cases are within safe limits. Additionally, they are required to display proper signage and warnings informing consumers about the use of CO and providing instructions for safe handling and storage of meat products.

Some countries and jurisdictions have banned the use of carbon monoxide in meat preservation, while others have strict regulations and limits on its use. Consumers are advised to be aware of these regulations and to make informed choices when purchasing meat products.