RETARDING DETERIORATION OF TABLE GRAPES WITH IN-PACKAGE SULFUR DIOXIDE GENERATORS WITH AND WITHOUT REFRIGERATION
Inoculated 'Thompson Seedless' grape packs (V. vinifera L.) held at 25°C in unvented poly liners with a QR generator had no decay until the fourth day. Grapes with a modified QR generator (2.7 g NaHSO3) had no decay until the fifth day. Fruit in a poly liner with 6 mm diameter vents on a 112 mm spacing (0.23% vented area) had significantly more decay than that in an unvented liner packed with either the 1.5 or 2.7 g generator. A vented area of 0.92% generally increased decay but with an area of 3.68% decay was less. Drying and browning of stems and softness of berries was related directly to the amount of vented area. The three SO2 treatments significantly retarded browning of stems and the amount of browning was related inversely to dose of SO2. Weight loss was 0.1% after six days for grapes in an unvented liner, but was 3.75% if the liner had 0.23% vented area. With 0.92% vented area the loss was 4.3% and with a vented area of 3.68% the loss was 6.5%. This last value exceeds significantly the 5.7% weight loss for the vented Kraft liner.