To avoid spoilage, the temperature, humidity and airflow in butcher refrigerators have to be monitored constantly. Depending on the type of meat and the species, we refrigerate carcasses before cutting. It is important that the carcass is in prime condition and clean before processing.
Refrigerating a carcase too soon will have an adverse effect. The internal muscle temperature has to be allowed to decrease slowly before refrigeration begins. If not a process called “cold shortening” will make the meat tough. Carcasses should cool at 16 degrees C for 16 hours.
The carcass is usually vacuum sealed after is cut and boned. This extends the shelf life by removing oxygen from the packaging. (Microbes need oxygen to multiply).
If you open a vacuum sealed pack, sometimes there will be a smell. A mild rotten egg is one way to describe it. This usually goes away in less than an hour and is from the vacuum packing process.
So, by the time you buy beef cut into steaks, it may have been maturing for up to 28 days.
The aging process has to be carefully monitored for beef to tenderize so that it is at its best.
Enzymes in meat break down the fibres and over a period of about 20 + days the tenderization occurs. You could eat meat two days after slaughter but it will be tough and lacking in flavor.
There is also a process called Modified Atmosphere Packaging. (MAP) that replaces oxygen with gas that retards microbial growth in the pack.
Meat cut from quarters into primals, then deboned and cut into steaks, ground beef and roasts.
Discoloration happens faster when the meat surfaces are exposed to air