Poultry and poultry products are highly perishable foods because of their high moisture content, rich nutrient composition, and near-neutral pH, which provide ideal conditions for the growth of spoilage microorganisms. Spoilage begins immediately after slaughter if hygienic handling and proper refrigeration are not maintained. The major sources of contamination include feathers, skin, intestinal contents, processing equipment, water, air, and handlers. Improper processing, cross-contamination, and inadequate storage significantly increase the rate of microbial spoilage. The principal spoilage microorganisms in poultry include species of *Pseudomonas*, *Acinetobacter*, *Moraxella*, *Brochothrix thermosphacta*, *Lactobacillus*, *Enterobacter*, *Proteus*, and various yeasts and molds. Under refrigerated aerobic conditions, *Pseudomonas* species are the dominant spoilage organisms because they grow rapidly at low temperatures. Under vacuum or modified atmosphere packaging, lactic acid bacteria become more significant. In frozen poultry, microbial growth is greatly slowed, but surviving microorganisms can multiply after thawing if temperature abuse occurs. Spoilage in poultry is characterized by unpleasant odors, slimy surface formation, discoloration, off-flavors, and soft or sticky texture. Protein degradation by bacteria produces ammonia, hydrogen sulfide, amines, and other volatile compounds responsible for foul odors. Lipid oxidation also contributes to rancidity, especially in fatty poultry products. Molds may grow on processed poultry products stored under humid conditions, causing visible fungal colonies and quality deterioration. Processed poultry products such as sausages, nuggets, burgers, and smoked meat may undergo spoilage because of inadequate heat treatment, post-processing contamination, or improper storage. Vacuum-packed products may spoil due to lactic