SULPHURATING OF TABLE GRAPES

For table grapes it is necessary to use a special technique of preserving and an adequate refrigerator equipment, which differ from the common systems adopted for other fruit and vegetable products. Regarding the grapes' sensitivity to a weight decrease during refrigeration, and their vulnerability as for fungi (botrytis Cinerea), a solution was found in an equipment series which allows for the preservation as well as the treatment of this product, for a better distributed and more constant commercialization, ensuring optimal phytosanitary properties. The use of special concentric plastic panels with the cells, under which the product is placed, leads to indirect refrigeration guaranteeing a very high relative humidity of about 95% - 98%. Within these panels, special ventilators contribute to the ventilation with consequent thermic exchange between the product and the external refrigerator plant.

The adding of gas treatment on a basis of sulphur dioxide for short periods, with product temperatures near zero, complete the treatment. The cutting down of sulphur dioxide SO2 is achieved by washing the treated air with countercurrent water, by means of a washing tower of stainless steel.

All the structures which form part of the plant, including the evaporator of sulphur dioxide SO2, are made of non corrosive material, stainless steel or PVC.