A: "In the early days of retailing, all products generally were fetched by an assistant from shelves behind the merchant's counter while customers waited in front of the counter and indicated the items they wanted. Also, most foods and merchandise did not come in individually wrapped consumer-sized packages, so an assistant had to measure out and wrap the precise amount desired by the consumer. These practices were by nature very labor-intensive and therefore also quite expensive. The shopping process was slow, as the number of customers who could be attended to at one time was limited by the number of clerks employed in the store.

The concept of a self-service grocery store was developed by American entrepreneur Clarence Saunders and his Piggly Wiggly stores. His first store opened in Memphis, Tennessee, in 1916. Saunders was awarded a number of patents for the ideas he incorporated into his stores[1][2][3][4]. The stores were a financial success and Saunders began to offer franchises. The Great Atlantic and Pacific Tea Company (A&P) was another successful early grocery store chain in Canada and the United States, and became common in North American cities in the 1920s. The general trend in retail since then has been to stock shelves at night so that customers, the following day, can obtain their own goods and bring them to the front of the store to pay for them. Although there is a higher risk of shoplifting, the costs of appropriate security measures ideally will be outweighed by the increased economies of scale and reduced labor costs.

Early self-service grocery stores did not sell fresh meats or produce. Combination stores that sold perishable items were developed in the 1920s.[5]

Historically, there was debate about the origin of the supermarket, with King Kullen and Ralph's of California having strong claims.[6] Other contenders included Weingarten's Big Food Markets and Henke & Pillot.[7] To end the debate, the Food Marketing Institute in conjunction with the Smithsonian Inst