The term 'Dark Cutting' is used for meat that does not bloom or brighten when it is cut and exposed to air. Beef customers prefer beef cuts to be a bright pinkish colour at retail, they avoid dark coloured meat. Dark cutting beef (DCB) is largely linked with stress and the mobilisation of muscle glycogen—energy store—in the live animal prior to slaughter.
In the time between slaughter and chilling, a chemical reaction known as glycolysis occurs in the muscle tissue. This reaction converts glycogen into lactic acid. This lactic acid causes the meat pH to decline from the neutral value of 7.2 found in the live animal. The amount of pH fall is determined by the quantity of glycogen available in the muscle for conversion to lactic acid.
Desirable eating table beef has an ultimate pH in the range of 5.3 to 5.7. If the quantity of glycogen in the muscle tissue was low, and the pH remains above 5.8, then DCB is a likely outcome.
In addition to the unacceptable appearance, DCB has the following characteristics:
- a high water holding capacity – so the meat loses a lot of moisture during cooking and becomes very dry;
- reduced shelf life – bacteria grow more rapidly due to the higher pH and moisture;
- a sticky texture.
