PURPOSE: To enable the storage of fresh salad for about 7W10 days at normal temperature in vacuum and for about 1 month in refrigerated state in vacuum, by treating fresh green vegetables with potash alum, potassium chloride, etc.

CONSTITUTION: Short and small pieces of fresh green vegetables are washed with about 0.5% aqueous solution of potash alum, immersed in a 0.1W0.3% aqueous solution of potassium chloride, and pressurized under a pressure of about 3W4kg/cm2 for 20W30min at least once during the immersion process. After the completion of immersion, the drained green vegetables are immersed in a mixed aqueous solution containing 0.2W0.4kg of calcium phosphate, 0.09W0.2kg of ammonium chloride, 0.09W0.2kg of magnesium carbonate and 2W4kg of potassium chloride for 10W20min, taken out of the solution, drained, and dressed with mayonnaise or dressing.