Here's what i know of this subject.
If you mean after the slaughter, then the meat needs to be chilled as fast as possible. With the immediate chilling of the carcass below 7°C, we avoid the spoilage of the carcass due to the growth of spoilage bacteria. Also, the growth of pathogenic bacteria that may exist on the carcass is suspended. With the chilling, the final product will be softer and tastier, as it keeps the characteristics of the "fresh" meat, due to the slower reactions physicochemical reactions of the meat. Now, after the slaughter, the carcass should be tested by a veterinarian. This happens before the chilling, but it takes less than two hours for the specialist to take samples and test the carcass.
Always, leaving a product (that needs to be refrigerated) outside the fridge, causes spoilage and the growth of pathogenic and spoilage bacteria. Meat and dairy are a very sensitive group of products.