Fig. 1. Changes in pH of vacuum-packaged, sulphited, 50% N2–50% CO2 as well as 100% N2-treated Giant Red shrimp (GRS) samples during frozen storage (months). Error bars (n = 3) are smaller than symbols. Symbols used in the graph include: j: Vacuum; N: N2–CO2; 4: N2; s: Sulfited.