Optimal Packaging Conditions to Prolong Shelf Life of Lettuce (Lactuca sativa L.) in a Modified Atmosphere

Food preservation has always been a concern for mankind. Different methods have been developed to preserve food for long periods, such as cold storage, plastic covers, and modified atmosphereThis study examined the physicochemical and biological effects of a modified atmosphere on packaged Romaine lettuce at three levels (G1: 40% oxygen, 15% carbon dioxide, 45% nitrogen; G2: 70% oxygen, 15% carbon dioxide, 15% nitrogen; G3: 100% oxygen). The lettuce was packaged in 40 µm (P1) or 50 µm (P2) thick polyethylene at 4°C and stored for 16 days. The least polluted sample was G3 using P2, as assessed by the total number of microorganisms, mold and yeast. This sample was also in the best condition, as measured by pH and color. The highest percentage of weight loss was for G3 and P1; it also showed the greatest decrease in the percentage of soluble solid materials. The results showed that G3 and P1 was the best combination to preserve packaged Romaine lettuce. This combination was effective for two weeks of preservation.