The topics related to meat is very large and inexhaustible. However, I will share a few basic rules to you.
There are three types of meat: 1) freshly slaughtered, 2) chilled (matured), and 3) frozen.
Note the following:
• Don't buy meat at a doubtful places (especially at paces that are located on the side of the road)
• Do not buy meat that has signs of thawing / freezing for several times
• Do not buy meat on hot summer days that are not stored in the fridge
• Do not buy meat, if you notice at least 1 sign of spoilage (I have often heard about its cutting / throwing, which is wrong)
• When buying meat in the market, pay attention to the “seal” of examined / verified meat
As for the frozen meat and freezing in general, it significantly worsens the quality of meat (when frozen, it is generally frozen at -40 degrees and stored for 1-2 years, the price of which is certainly much lower than of fresh meat)
Frozen meat can be: 1) freshly slaughtered and 2) matured
Freshly slaughtered meat is soft, tender and juicy. However, within 4 hours of slaughter it becomes so solid that it is impossible to soften it even with thermal processing. It’s broth is not very useful as well (it is quite tasteless). If you still buy such meat, it is better to mature it in the fridge (at + temperature), it will soften in 1-2 days, the taste and smell will improve. The meat usually sold at the shops are 1-2 days matured meat, which is good.
It is advisable to use matured meat right away! unfrozen meat is considered fresh if: its skin is dry (i.e. it does not get wet when putting on a paper towel), the meat has a smell specific to its variety, the consistency of the meat is non-rigid and elastic (if you press finger a small hole should be filled immediately), the mass should be wet and not sticky. Tendons should be elastic and solid, the joints should be white, and fat should not be yellow.
Identifying of frozen and subsequently thawed meat - the meat is wet and when you put on a paper towel, it gets quite wet, the juice always comes out and it is not elastic. After pressing the finger, the hole does not get filled for a long time
Beef fat has a white, cream or yellowish coloring. Pork fat is soft and the color is white or light pink, while lamb fat is white and dense.