ABSTRACTCapsicum annuum (red sweet and hot cayenne) and Piper nigrum (black and white) pepper powders were evaluated for inhibition of oxidative reactions and extension of the shelf life of fresh pork sausages packaged in a modified atmosphere. Sausages containing either red sweet pepper or cayenne pepper (0.1%, 0.5%, or 2%) or black or white pepper (0.1%, 0.5%, or 1%) were packaged in a modified atmosphere of 80% O2+ 20% CO2, stored for 16 d in the dark at 2 °C, and analyzed each 4 d for pH, CIE L*, a*, and b*, 2-thiobarbituric acid-reactive substances (TBARS), psychrotrophic aerobes, sensory discoloration, and off-odor. Results demonstrated that Capsicum peppers (sweet red and hot cayenne) enhanced red color but failed to prevent discoloration, whereas they were very effective in inhibiting lipid oxidation, chiefly at the highest concentration used (2%), which resulted in a delay of off-odor formation. Piper peppers (black and white) significantly delayed discoloration with small modification of sausage color; furthermore, they also inhibited lipid oxidation, which led to a delay of off-odor formation, particularly in the form of black pepper. Besides this, all those spices inhibited microbial growth when added at the highest concentration (1%Piper and 2%Capsicum).