The standard grades for table stock potatoes shall be limited to U.S. extra number 1 grade, U.S. number 1 grade, U.S. commercial grade, and U.S. number 2 grade and unclassified, and shall conform in all respects and be identical with the latest standards established by the United States secretary of agriculture for the grades herein mentioned, and thus conforming shall be accepted as the legal standards for the state. A and B size or any other size designation with the U.S. number 1 grade, U.S. commercial grade and U.S. number 2 grade shall be in accordance with the U.S. standards for potatoes. Standard grades shall also include a superior grade to be defined by rules promulgated by the commissioner of agriculture under this act and which would be entitled to a seal of quality under Act No. 70 of the Public Acts of 1961, being section 289.631 to 289.646 of the Compiled Laws of 1948. Potatoes for table use shall not be sold that do not meet the requirements of the foregoing grades unless designated as unclassified. Unclassified potatoes may be sold in consumer size packages if the packages are color coded and marked “unclassified”. The word “unclassified” shall be as large as the largest lettered word on the package and in no event be less than 1 inch in height.