There was a small amount of MetMb observed in CO-MAP steaks
since about 0.2% residual oxygen was detected in the primary headspace
gases, but the MetMb% was limited over time. This was likely
because carboxymyoglobin is much more stable against oxidation
than oxymyoglobin, due to the stronger binding of CO to the ironporphyrin
site on the myoglobin molecule (Wolfe, 1980).