Exposure to light can affect the color of certain types of meat, including beef. Changes in color can also be caused by the process in which the meat is cured.
Spoiled meat changes in texture and becomes sticky or slimy. Meat that has gone bad produces a foul or unusual odor. If the meat is fading in color, this can also indicate spoilage.
Color changes on meat that occur in the freezer do not pose a food-borne illness threat, but can alter the taste and quality.Learn more about Meat