Sunshine Dairy, a dairy products supplier known for the big, spinning milk carton on its Northeast Portland roof, filed for Chapter 11 bankruptcy this week and said it will close the historic location.

Sunshine said it will continue to operate a separate location on Northeast Halsey but will close its 83-year-old site on Northeast 21st Avenue. Portland competitor Alpenrose Dairy will take over operations at the plant on 21st but will move production to its own facilities.

Some of Sunshine's 100 employees will remain with the company, and some will join Alpenrose, according to Dan Boverman, who steps in as chief restructuring officer. "There will be some job loss," he said, but declined to estimate how many people face layoffs.

The 21st Avenue location will close sometime in the next several months, according to Boverman, as production transitions to Alpenrose. He said the 39,000-square-foot plant, in a prime location near Interstate 84, "will be repurposed to its highest value." The site has distinctive industrial zoning that allows for residential and mixed-use development.

Sunshine's bankruptcy reflects changing dynamics in the dairy industry, Boverman said, driven primarily by consolidation among dairy producers and grocery chains, which has given the supermarkets more pricing power.

The bankruptcy filing indicates Sunshine Dairy owes more than $12 million, including $9 million to a Wisconsin Bank, First Business Capital Corp. Sunshine says its assets are worth less than $10 million. Adam Stein-Sapir of Pioneer Funding Group first noted the filing.

Sunshine Dairy's official corporate history says a Greek restaurateur named John Karamanos started the company in the 1930s to serve his colleagues in Portland's food industry. Sunshine describes itself as a fourth-generation, family-owned dairy processor.

Sunshine sells milk, cream, butter, yogurt and cheese at in the Northwest groceries under the Sunshine brand and also supplies dairy products to restaurants and coffeeshops including Burgerville, Elephants Delicatessen, Grand Central Bakery and Stumptown Coffee Roasters. Boverman said Sunshine will continue selling products made at the Halsey site.

-- Mike Rogoway; twitter: @rogoway; 503-294-7699