Effect of Modified Atmosphere Packaging (MAP) Varying in CO₂ and N₂ Composition on Quality Characteristics of Dry Fermented Sausage During Refrigeration Storage

The current study investigated the effects of the most suitable modified atmosphere packaging (MAP) on the physicochemical, microbiological, and sensory properties of fermented dry sausages during 45 days of refrigeration (4ºC) storage period. Treatments were vacuum-packed (control), 25% CO₂/75%N₂ (MAP1), 50%CO₂/50%N₂ (MAP2), 70%CO₂/30%N₂ (MAP3) and 100% CO₂ (MAP4). All MAP samples regardless of their CO₂ composition significantly (p<0.05) decreased in pH, a_w, total plate count (TPC), and LAB count values as compared to the vacuum package during storage. The Enterobacteriaceae count in all MAP packaging was significantly (p<0.05) lower than the vacuum-packed samples and counts in MAP3 and MAP4 samples were markedly (p < 0.05) lower than all other treatments in prolonged storage of 15 and 45 days. Based on the TBARS content at day 15 and 30 storage time, treatments are ranked as follows: vacuum-packed >MAP1 >MAP2 >MAP3>MAP4. The* value of MAP4 was higher than all other treatments. In the final storage days, no variation was exhibited (p>0.05) among treatments in lactic acid aroma and sourness, and MAP2 samples had the lowest (p<0.05) overall acceptability. The use of MAPs with an increase in the CO₂ from MAP1 to MAP4 samples can help in better microbial inhibition than vacuum package, and 70%CO₂/30%N₂ (MAP3) and 100% CO₂ (MAP4) were effective to maintain several quality parameters (a_w, pH, microbial inhibition, stability against lipid oxidation, and instrumental color traits) and extend the shelf life of dry fermented sausage.