When properly packaged, meat generally retains the colors of bright red or a light pink only occasionally marbled with or covered with light-white layers of fat; this coloring usually is looked upon as a sign of freshness. However, on occasion, meats appear brown before cooking. While this is typical after cooking for red meats and white meats that have been roasted or caramelized, it can be disconcerting in fresh or frozen uncooked portions. For the three most common meats -- beef, pork and chicken -- this coloring can indicate different things.
Fresh ground beef typically is red on the exterior and brown on the interior. This is because the surface meat is exposed to air, and oxygen enhances the bright-red look, while the internal meat remains brown within this exposure. However, prolonged exposure to air also can create a brownish shade, but this does not mean the meat cannot be eaten. Do not use the color of beef to indicate consumption safety; check that the fresh meat is being eaten before the use-by date, or within three to five days of the sell-by date for beef cuts and within one to two days for ground beef.
Oxidation, or exposure to air and the oxygen within it, also affects pork in a similar way as beef. While not as originally vibrant as its cow-based counterpart, pork turns brown on the outside if continuously exposed to air. However, this does typically mean the pork has gone bad, and is one of the most common ways of telling. It often is accompanied by a bad smell. Discard any pork immediately if it begins to exhibit these traits.
Changing colors in white meats, such as poultry, is fairly typical. This generally happens as the meat ages, becoming slightly more gray. However, brown is not the usual color for fresh poultry, and can indicate spoilage. Similar to beef and pork, a main means of determining whether meat has spoiled is through the combination of this color change with an off smell or a slimy feel. Chicken and other poultry also spoil quickly, so ensure the raw meat is used prior to the "best before" date.
Do not use meat after the "best before" date unless it was frozen before this time and has been stored properly at 0 Fahrenheit or below. Always ensure it is stored in a refrigerator set to 40 degrees Fahrenheit or below, and has not been left out for more than 30 minutes at room temperature. If the meat has not been stored properly or has been exposed to room temperature for longer than 30 minutes, discard the meat immediately, as this can cause bacteria to grow.