Thermochemically modified lysozyme was added to pork meat packaged in preservative gas atmospheres (10% N-2, 20% CO2, 70% O-2) and stored at 4 +/- 1 degrees C for 26 days. The modified enzyme exhibited an antibacterial action against Pseudomonas and Enterobacteriaceae bacteria. The surface application of the lysozyme resulted in retardation of adverse change's in aroma of the meat. No significant effect of the enzyme on pH and colour of the meat was obsd.