Don’t get fooled by the supermarkets. They’re selling you meat from… See more

Bright red beef often attracts shoppers because many people associate redness with freshness. Color, however, is influenced by oxygen, packaging, lighting, animal age, and the muscle pigment myoglobin. A vivid display is not proof that one package is newer or safer than a darker package beside it.

Fresh beef protected from air in a vacuum package can appear burgundy or purplish. After exposure to oxygen, myoglobin forms oxymyoglobin and the surface becomes cherry red. Continued oxygen exposure and store lighting can eventually create brownish red metmyoglobin. The United States Department of Agriculture notes that color change alone does not necessarily mean spoilage.

Shoppers should consider several signs together. Check the use by or sell by information, refrigeration, package integrity, and the amount of liquid present. Avoid packages that leak, are swollen, or have broken seals. Meat with an off odor or tacky, sticky texture should not be used even if some areas still look red.