n. — Ontario & Manitoba
milk sold in returnable jugs; often in a compound, as in jug milk store.
Type: 2. Preservation — In the early 1950s, dairy producers in the US and Canada began selling milk in jugs as a way to drop prices and increase consumption. Becker's Milk, an Ontario-based chain, claimed to be the first company in Canada to sell jug milk (see Image 1 and the 1957 quotation). The term appears frequently in US and Canadian newsprint during that decade, but attestations taper off in the US in the 1960s. In Canada, however, the term retained currency until much more recently, and has only been in decline since the late 2000s.
Internet domain searches, shown in Chart 1, demonstrate the high frequency of jug milk in Canada, with Ontario leading (see Chart 2).
See also COD-2, s.v. "jug milk", which is marked "Cdn (Ont.)", Gage-5 , s.v. "jug milk outlet or store", which redirects to "convenience store".