Raw poultry meat sausages in natural casing of 15 mm diameter, packed into PolyEthylene Terephthalate (PET) trays conditioned under modified atmosphere (selected gas mixture 50%/50% (CO2/N2)) were purchased from a local producer, and used as experimental material. Poultry sausages contained poultry meat (78%), pork fat, water, glucose, acidifying agents and antioxidants, nitrite salt, and a mixture of spices and natural aromas with a shelf-life of fifteen days. One hundred and forty four trays with sausages from the same batch were unpacked and divided into two equal groups of 72 trays and re-packed into PolyEthylene Terephthalate (PET) trays. Seventy-two trays were conditioned under modified atmosphere composed of a selected gas mixture 50%/50% (CO2/N2). The other 72 trays were packed under air. PET trays with sausages were wrapped by heat-sealing in a thin high barrier polyester-based film (PET/EVOH (Co-polymer of Ethylene and Vinyl alcohol)/PE (PolyEthylene)). The physical prop-erties of the packaging were as follows: oxygen transmission rate b5 cm3/m2•24 h−1•bar−1, CO2 transmission rate b25 cm3/m2•
24 h−1•bar−1 and water vapor transmission rate b5 g/m2•24 h−1• bar−1 at 23 °C and 85% relative humidity.
Packages had a headspace volume ratio of 1/3:2/3 (product:gas). The sausages were purchased three days after production and imme-diately treated by high pressure processing. Between production and purchase, sausages were stored at 4 °C.