What factors affect the color of meat and poultry?
Myoglobin, a protein, is responsible for the majority of the red color. Myoglobin doesn't circulate in the blood but is fixed in the tissue cells and is purplish in color. When it is mixed with oxygen, it becomes oxymyoglobin and produces a bright red color. The remaining color comes from the hemoglobin which occurs mainly in the circulating blood, but a small amount can be found in the tissues after slaughter.
Color is also influenced by the age of the animal, the species, sex, diet, and even the exercise it gets. The meat from older animals will be darker in color because the myoglobin level increases with age. Exercised muscles are always darker in color, which means the same animal can have variations of color in its muscles.
In addition, the color of meat and poultry can change as it is being stored at retail and in the home (see explanation in question 5). When safely stored in the refrigerator or freezer, color changes are normal for fresh meat and poultry.
Does a change in color indicate spoilage?
Change in color alone does not mean the product is spoiled. Color changes are normal for fresh product. With spoilage there can be a change in color -- often a fading or darkening. In addition to the color change, the meat or poultry will have an off odor, be sticky or tacky to the touch, or it may be slimy. If meat has developed these characteristics, it should not be used.
If the color of meat and poultry changes while frozen, is it safe?
Color changes, while meat and poultry are frozen, occur just as they do in the refrigerator. Fading and darkening, for example, do not affect their safety. These changes are minimized by using freezer-type wrapping and by expelling as much air as possible from the package.
What are the white dried patches on frozen meat and poultry?
The white dried patches indicate freezer burn. When meat and poultry have been frozen for an extended period of time or have not been wrapped and sealed properly, this will occur. The product remains safe to eat, but the areas with freezer burn will be dried out and tasteless and can be trimmed away if desired.
Provided by the United States Department of Agriculture