Description
Carbon monoxide (CO) is a colorless, odorless, and tasteless
gas that is slightly lighter than air. It is toxic to humans and
animals when encountered in higher concentrations, although it is
also produced in normal animal metabolism in low quantities, and is
thought to have some normal biological functions. In the atmosphere
it is spatially variable, short lived, having a role in the
formation of ground-level ozone.
Meat coloring
Carbon monoxide is used in modified atmosphere packaging
systems in the US, mainly with fresh meat products such as beef,
pork, and fish to keep them looking fresh. The carbon monoxide
combines with myoglobin to form carboxymyoglobin, a
bright-cherry-red pigment. Carboxymyoglobin is more stable than the
oxygenated form of myoglobin, oxymyoglobin, which can become
oxidized to the brown pigment metmyoglobin. This stable red color
can persist much longer than in normally packaged meat. Typical
levels of carbon monoxide used in the facilities that use this
process are between 0.4% to 0.5%.
The technology was first given "generally recognized as safe"
(GRAS) status by the U.S. Food and Drug Administration (FDA) in
***2 for use as a secondary packaging system, and does not require
labeling. In ***4 the FDA approved CO as primary packaging method,
declaring that CO does not mask spoilage odor. Despite this ruling,
the process remains controversial for fears that it masks spoilage.
In ***7 a bill was introduced to the United States House of
Representatives to label modified atmosphere carbon monoxide
packaging as a color additive, but the bill died in subcommittee.
The process is banned in many other countries, including Japan,
Singapore, and the European Union
