MEAT SPOILAGE
Storage of meat should be approached with dilligency. If we don't treat our meat properly, it will become infested with bacteria and break down into a stinking piece of garbage. When you buy meat, you should look for firmness, nice color and surface (not brown and slimy, but red and shiny), good moisture, and no offending smell - just fresh and nice piece of meat. Other than that - you should stay away from it. Remember though that from the time you purchase your meat, it is your responsibility to keep it reasonably fresh and prevent it from spoiling.
There are basically two common ways in which a meat can become spoiled. Microbes and oxidation. Both of these damaging factors can be controlled though. Bacteria and mold, as you might know, can be slowed down or destroyed by a proper temperature. These small living creatures are normally sticking to the surface of the meat, and they get there during the processing of the meat or simply from the air that is normally full of mold spores. The most easily spoiled meats are poultry or other birds, as well as fish - these have to be obtained and eaten as fresh as possible. Beef and pork are more resistant, but not uninvincible! The common result of bacterial or mold spoilage is stinking smell, accompanied by a slimy and discolored surface of the meat. You don't need a very trained nose to detect bacterial spoilage. If you want to attempt to save the meat by cutting away the spoiled surface, remember that some bacteria may have produced toxins that could poison you. Although it is not that common, it can happen, depending on what type of bacteria colonized your meat.
Microbal growth is prevented by cold or hot temperature. In practical terms, keep your meat in refrigerator until you start preparing it, and once cooked, serve it right away. If you still want to store cooked meat for a later occasion, cool it down quickly on an ice bath and then put it into the refrigerator. It may sound like overdoing the safety routines, but as long as the meat is kept between cold and hot, new bacteria will attach to it and start to grow there. And the longer time we keep it in this temperature interval, the number of bacteria will increase dramatically (or exponentially, in mathematical terms).
Oxidation is a tougher problem to tackle, as oxygen is everywhere around us. Naturally, the best way would be to package the meat in vacuum-packets, although this is not very common. However, meat in vacuum can stand on a shelf for a very long time without being spoiled, e.g. beef can stand the test of 12 weeks without rotting. Let's get real though. We usually buy our meat in air-filled packages, or just wrapped in some paper. This means of course that oxygen will quickly spoil the meat if we don't eat it soon enough. Even cooked meat is prone to oxidation, so don't keep your stews for too long in the refrigerator either. If you still want to fight the oxygen, wrap your meat in an air-tight wrap (e.g. Saran wrap) and put it in the refrigerator.
What about freezing? In terms of prevention of meat spoilage, freezing is the best way to do it. After all, we have found mammoth meat of 15,000 years of age, well frozen and still preserved so one could safely eat it (I wonder how a mammoth tastes?). However, freezing severely changes the quality of the meat. The muscle tissue becomes damaged as the water freezes to ice crystals and disrupts the fine muscular network. When we thaw such meat, the ice crystals melt to water, leak out, and leave the punctured meat behind them. We get a destroyed, watery meat. As it's cooked, even more water leaks out from the meat, making it readily dry. Not really the result we want! If you still want to freeze the meat, make sure the freezing is quick (smaller ice crystals form), and when you thaw it, do it in a refrigerator or in a cold water bath. Never thaw your meat in room temperature - you will just optimize the growth capacities of bacteria. Besides, air is not an efficient heat conductor. Water, on the other hand, is much more efficient, even if it's colder than the air. Also remember that you can cook frozen meat directly, without thawing it first, but it takes longer time and is not suited for quick-cooking methods.