65 ILCS 5/11-53-4

The corporate authorities of each municipality may require all grain, flour, meal, hay, feed, seeds, fruits, nuts, vegetables and non-liquid vegetable products, meats and non-liquid animal products, fish, butter, cheese and other similar dairy products, dry groceries and all other similar articles of merchandise, or any particular class or classes of the specified merchandise, in the absence of a contract or agreement in writing to the contrary, to be sold by standard avoirdupois weight or by numerical count.