Also check the packaging date or the best before date (or use by date) to ensure getting freshly packaged beef.
Good quality beef should have a rich, vibrant, reddish colour (photo right) but packaged beef can sometimes turn from red to an un-appetising bluish-red or greyish colour.
When off-colour meat products such as steaks, roasts and ground beef are left in the store or supermarket refrigerator, sometimes customers would complain to public health department about store selling “bad” meat.
No need to worry as discolouration of beef indicates a lack of exposure to oxygen due to the packaging. The beef will change to a brighter red colour (photo below) once it is removed from the packaging and expose to air.
What causes beef to change colour? Has it gone bad?
Beef, especially ground beef often undergo discolouration prior to spoilage but still safe to eat after cooking to a safe internal temperature 71°C (160°F). Beef contains a pigment in the muscle tissues called Myoglobin and this pigment is normally a dark greyish-purple colour.
After cutting or slicing, the beef comes into contact with oxygen and turns myoglobin into oxy-myoglobin through oxidation. Oxy-myoglobin is a deep red colour pigment that gives beef the supermarket “fresh red meat look”.
When freshly cut or ground beef is packed into an air tight package or vacuumed bag, the beef can turn into a greyish colour when deprived of oxygen, especially when kept in the package for a few days. Problem is, consumers do not find greyish colour beef very appetising as they often associate greyish colour as spoilage and off-colour meat as rotten meat. So for the purpose of merchandising, the store often infused meat packaging or bag with oxygen or other gases (nitrogen, carbon dioxide) to prevent discolouration of beef.
Is the off-colour beef still safe to eat or should you throw it out?
Even if there is a colour change in the beef, which might not be as visually appetising but the meat is still fine to eat. However, make sure the beef is stored properly in the refrigerator or freezer and consumed within a short period of time. Always cook meat to a safe internal temperature, especially for ground beef items such as burger and meat loaf that should be cooked to an internal temperature of 71°C (160°F) (Safe cooking temperatures).
However, if the package of beef is off-colour all the way through and does not turn red when exposed to air within fifteen to twenty minutes, it is most likely spoiled and can increase the risk of food poisoning. Also, spoiled beef usually has a sulphurous or foul smell and often with a slimy surface and should be tossed.
Certified Public Health Inspector, Canada
Jim Chan began his career as a Public Health Inspector at Toronto Public Health in 1977 after completing his science degree at University of Guelph and the Environmental Health program at Ryerson University. Throughout his 36-year career, Jim has been responsible for managing and implementing programs and activities dedicated to the protection of public health. Programs such as Food Safety Inspection (DineSafe Toronto), Communicable Disease Control (including case management during the SARS outbreak in 2003 and health & safety during the H1N1 outbreak in 2009), Infection Control, Tobacco Control Enforcement and Health Hazard Investigation.
Jim retired on October 31, 2013 from Toronto Public Health. After retirement, Jim began an interesting career as a food safety consultant to media outlets & on-air guest in various TV shows, presenting at conferences and workshops, developing food safety training materials, and promoting public health and food safety using social media. Jim’s recent adventure is teaching a food safety course to public health inspectors at Conestoga College, School of Health & Life Sciences in Kitchener, Ontario, Canada.
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