Pet Milk Company stock certificate circa 1965

Cool collectible stock with a nice vignette of two Greek male figures flanking the PET logo,  Issued and cancelled. Dated 1965.

Pet, Inc., was an American company that was the first to commercially produce evaporated milk as a shelf-stable consumer product and later became a multi-brand food products conglomerate. Its signature product, PET Evaporated Milk, is now a product of The J.M. Smucker Company. PET Dairy is a regional brand of fresh and processed dairy products in the Southeastern United States made by the Land-O-Sun division of Dean Foods. Many of the remaining brands once owned by Pet, Inc. are currently part of General Mills.

Evaporated milk was a popular product before refrigerators were common in homes, but is now a niche product mainly used in baking and other recipes. PET anticipated the change, and transformed into a food products conglomerate through a series of acquisitions. It was also the subject of acquisitions, primarily due to its Old El Paso line, Progresso line, and other brands, and not because of the evaporated milk. Progresso soup cans presently maintain the copyright notice of Pet, Inc.

John Baptist Meÿenberg (1847-1914) was an operator at the Anglo-Swiss milk condensery at Cham, Switzerland. Anglo-Swiss made sweetened condensed milk. From 1866 through 1883, Meÿenberg experimented with preservation of milk without the use of sugar. He discovered that condensed milk would last longer if heated to 248°F in a sealed container, and hence could be preserved without adding sugar. When Anglo-Swiss declined to implement Meÿenberg's work, he resigned from the company and emigrated to the United States. John Meÿenberg first moved to St. Louis, but soon transferred to Highland, Illinois, due to its large Swiss population. In 1884, U.S. Patents (Apparatus for Preserving Milk) and (Process for Preserving Milk) were issued to Meÿenberg. Meÿenberg associated with various local merchants, including John Wildi, Louis Latzer, Dr. Knoebel, George Roth and Fred Kaeser and, on February 14, 1885, organized the Helvetia Milk Condensing Company.

The company commenced operations in a closed wool factory. Helvetia started processing 300 gallons of raw milk a day. On 8 July 1885, the steam-powered sterilizer exploded and Helvetia Milk Condensing Company closed operations for repairs. Milk canned in early 1886 spoiled. Although John Meÿenberg believed that cans were inadequately sealed, others claimed that Meÿenberg's sterilization process was the cause. Due to this criticism, Meÿenberg left in August 1886. In 1899, Meÿenberg assisted Elbridge Amos Stuart in producing Carnation Evaporated Milk.

Louis Latzer assumed the role of technical director. He determined that the spoilage was caused by bacteria and resolved the problem. John Wildi was instrumental in marketing the product nationally and internationally, especially in areas where fresh milk or refrigeration were scarce. In 1895, the company registered the Pet trademark. In 1907, John Wildi separated from the company and organized the John Wildi Evaporated Milk Company in Columbus, Ohio. During World War I, American troops referred to a Helvetia milk can as a "Tin Cow". In 1923, the Helvetia Milk Condensing was renamed the Pet Milk Company after its signature product "Our Pet Evaporated Cream". In 1929, Pet established the PET Dairy division by acquiring a fluid milk processing plant in Johnson City, Tennessee.

In 1950, Pet Evaporated Milk sales peaked. Transformed into a food products conglomerate with the purchase of many brands in the early 1960s, including C. H. Musselman, Whitman's, Downyflake, and R. E. Funsten.cChanged name to Pet Incorporated in 1966 and merged with the Hussmann Refrigerator Company.In 1968, Pet acquired the Mountain Pass Canning Company, maker of the Old El Paso brand of Mexican food products. Acquired by IC Industries (ICI) in 1978. Hussmann and Pet were made into separate divisions of ICI. In 1981, ICI sold off the Musselman division. In 1982, the William Underwood Company was acquired, bringing with it the brands B&M and Ac'cent.

In 1985, the PET Dairy division was sold to the Challer Foods subsidiary of Finevest Dairy Holdings. This did not include the canned milk products. In 1986, Pet acquired Ogden Food Products (including the brands Progresso, Las Palmas, Hollywood, and Hain) and Primo Foods, an Italian foods marketer. in 1988, ICI changed its name to Whitman Corp. Acquired Orval Kent, a prepared salad maker, in 1989. In 1990, Pet, Inc. was spun off of Whitman.

In 1993, Pet sold the Whitman's chocolate brand to Russell Stover Candies. In 1995, Pet was acquired by the Pillsbury Company division of Grand Metropolitan. Major brands of interest are Old El Paso and Progresso. In 1997, Grand Met merged with Guinness to form Diageo. In 1999, Pillsbury sold the William Underwood business to B&G Foods. In 2000, General Mills acquired Pillsbury (incl. Pet) from Diageo. In 2001, to satisfy the US FTC, Diageo and General Mills agreed to sell several, but not all, Pillsbury brands to International Multifoods. This included the PET Evaporated Milk and PET dry creamer products. In 2004, The J.M. Smucker Company acquired Multifoods.