TY - JOUR T1 - Two-Stage Generation of Sulfur Dioxide within closed Containers to Control Decay of Table Grapes JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 290 LP - 301 DO - 10.5344/ajev.1966.17.4.290 VL - 17 IS - 4 AU - K. E. Nelson AU - J. P. Gentry Y1 - 1966/01/01 UR - http://www.ajevonline.org/content/17/4/290.abstract N2 - A two-stage system for controlled generation of sulfur dioxide to retard spread of decay from Botrytis cinerea Pers. in packed table grapes was developed for closed containers holding 27 pounds of fruit, either: 1) unvented telescope paraffin-plastic-coated corrugated paper; or 2) wooden lugs with completely closed polyethylene-coated chip-board liners. For the first-stage system, tissue-paper packets containing sodium bisulfite were distributed evenly in excelsior cushion pads above and below the fruit. Dose per container was 1.8-5.4 grams, divided among 12 packets. For the second-stage, sodium bisulfite was sealed in paraffin-coated tubes of 2 x 150 mm evenly spaced in the pads. Dose per container was 4.8-10.8 grams, distributed in 6 tubes. Packed containers were closed, precooled, and stored at 31 °F. Within 2 hours of closure, first-stage sulfur dioxide was detected, in some experiments reaching maximum concentration (12-40 ppm, depending on dose) by the second day. The second-stage system started generating sulfur dioxide after 5 days reaching maximum concentration (2-40 ppm) by the 12th day. Containers with high second-stage doses still contained 2-4 ppm of sulfur dioxide in the air at 53 days. Low-dose treatments were exhausted in about 40 days. For periods up to 30 days, high-dose first and second stages gave decay control equal to or better than that in the control—vented containers fumigated initially with sulfur dioxide and weekly thereafter. However, this dose caused appreciable bleaching. The low-dose first and second stages produced less or no more bleaching than that in the controls. Berries and stems in closed containers were conspicuously more turgid and fresh than those in the controls, because of considerably less water loss. Storage temperatures to 39°F had no effect on exposure to sulfur dioxide but did increase spread of decay. A simulated export shipment test demonstrated that the two-stage system without sawdust protected grapes from decay as well as the NaHSO3-sawdust method now used. ER -