Storage Life of Selected Meat Sandwiches at 4°C in Modified Gas Atmospheres

The refrigerated storage life of selected meat sandwiches packed in elevated carbon dioxide atmospheres with air or nitrogen was studied by acceptability scores of untrained panelists and by microbiological analysis. Commercially produced sandwiches, including processed meats, roast beef and hamburgers, were packed in gas impermeable film with 50% CO₂ and 50% air, stored at 4°C, and compared with a frozen reference sample. Processed meat products were still acceptable up to 35 d storage, roast beef for 28 to 35 d storage, and hamburger for only 14 d. The effect of gas atmospheres with 30, 50, or 70% CO₂ and either air or nitrogen, on acceptability of laboratory-packaged bologna, ham, roast beef, and hamburger, was also studied. The most significant effect was observed with hamburger samples, in which exclusion of oxygen extended storage life from 14 to 35 d. Initial product quality was a more important factor determining the length of storage life than the range of gas atmospheres between 30 and 70% CO₂, except for hamburger packaged in atmospheres containing air. A universal storage life for these products cannot be recommended. However acceptance of the products by an untrained taste panel generally extends beyond achievement of maximum microbial load.