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Sunday, 9 July 2017

What Colour Red Meat Should Be?

Beef Colour and Food Safety
by Jim Chan, Public Health Inspector (Retired)


(photo by Richard Yang)
When purchasing packaged fresh beef in a food store or supermarket, make sure the package is cold and the meat is firm. Inspect the packaging to ensure it is in good condition and should not have holes in the wrapping material. 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?


(photo by Erika Bartels)
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 (photo below). 


Is the off-colour beef still safe to eat or should you throw it out?  

(photo by Erika Bartels)
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


Food Safety - BBQ and Grilling 
(link)

Safe cooking temperature of meat 
(Video)

Food safety at home by Dr. Justin Beaver
 (Video)

Related links

BBQ Food Safety

Food Safety - Ground Beef, USDA

Gas mixtures help preserve the quality of packaged meat

Color of Meat and Poultry - USDA Food Safety

Meat Packaging

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