Under EU regulations, the ideal cucumber is 30 cm long with a curvature of some 10 mm for every 10 cm. Light curving cucumbers may have a curvature of 20 mm per 10 cm according to regulation No 1677 of 1988.
EU rules for cucumbers also cover shop sales, but it is not illegal to sell non-classified cucumbers. This differs from the rules on strawberries, which prohibit the sale of berries smaller than 18 mm in diameter.
EU rules on cucumbers and strawberries are often cited as examples of an EU obsession with regulating everything.
Notes
The United Nation Economic Commission for Europe, ECE, and the Organisation for Economic Co-operation and Development, OECD, have voluntary quality norms for fruit and vegetables, but at the wholesale level, not retail.