There are no U.S. standard grades for Swiss chard. Like all leafy greens, this vegetable should be fresh, crisp, not showing yellow or browned portions, and should be free of aphis or other insect infestation. It should be clean and cold. Unless it is under refrigeration, the quality is doubtful. Stalks that are wilted and rubbery will be tough and unsatisfactory.
Coarse stalks indicate pithiness.
This may be discovered by pressing or twisting the stalk. Losses Of Vitamin C During The Cooking Of Swiss Chard. Riboflavin Content Of Fresh And Processed Swiss Chard. Ascorbic Acid Content, Color, And Palatability Of Fresh And Processed Swiss Chard And Beet Greens. Acceptance Of Twenty-Six Vegetables.