TY - JOUR T1 - Patterns of Sulfite Residue Persistence in Seedless Grapes During Three Months of Repeated Sulfur Dioxide Fumigations JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 121 LP - 124 DO - 10.5344/ajev.1997.48.1.121 VL - 48 IS - 1 AU - Rodney K. Austin AU - Willena Clay AU - Samrane Phimphivong AU - Joseph L. Smilanick AU - Delmer J. Henson Y1 - 1997/01/01 UR - http://www.ajevonline.org/content/48/1/121.abstract N2 - In 1989, the United States Environmental Protection Agency instituted a sulfite tolerance of 10 µg SO2 per gram in grapes (Vitis vinifera L.). Accordingly, the residues resulting from repeated weekly SO2 fumigations of table grapes in storage, a typical industry practice, are a concern. In a simulation of commercial practices, grapes (cv. Thompson Seedless) were fumigated once a week with 2000 or 5000 µL SO2 per liter of storage volume and aerated 30 minutes while stored at 0°C for at least fourteen consecutive weeks. Each week, grapes were frozen immediately after aeration or stored at 0°C, 10°C, 20°C, or 30°C for 24 hours. The mean SO2 concentration for the treatment with the highest residues was 2.3 µg/g (5000 µL/L dose, seven fumigations). The maximum residue levels at each dose level were observed between the seventh and eleventh weekly fumigations. The influence of post-fumigation temperature on sulfite residue loss was minor and inconsistent. These data suggest that current industry practices leave sulfite residues well below the official legal tolerance. ER -