KANSAS CITY — Workers at three of the four snack cake plants operated by Hostess Brands L.L.C. have voted to unionize, according to the union representing the bakery workers.

The three plants are located in Indianapolis; Schiller Park, Ill.; and Columbus, Ga. The votes to unionize at the plants were confirmed by a spokesperson for the Bakery, Confectionery, Tobacco and Grain Millers International Union July 17. The spokesperson declined to elaborate further on the vote.

Representatives of Hostess offered Milling & Baking News a brief comment on the unionization vote but similarly declined to say much more about what transpired.

“We have always maintained that it would be up to our employees to determine whether they wanted to unionize or not,” the company said. “We respect the decisions of the employees who have chosen to do so at the three bakeries noted.”

The plants were acquired in 2013 as part of the $410 million purchase by HB Holdings L.L.C., an affiliate of Apollo Global Management L.L.C. and Metropoulos & Co., of most of the snack cake assets of Hostess Brands Inc.

Hostess operates a fourth plant, in Emporia, Kas. Significant production capacity expansions have been made at the Emporia plant since the 2013 acquisition.

The B.C.T.G.M. factored importantly in events that brought about the acquisition of the plants by HB Holdings. A November 2012 strike spearheaded by the B.C.T.G.M. precipitated a decision by Hostess to halt operations and liquidate its assets. Most of the company’s 36 baking plants remain closed 20 months later.

Four of the five snack cake plants acquired by Apollo and Metropoulos have reopened (the fifth, in Los Angeles has not), but a decision to operate the plants without unionized workers spurred criticism last summer from the B.C.T.G.M.

“The long-term viability of this effort is highly uncertain,” David Durkee, the union’s president, said in a July 2013 letter. “Rather than hire professional, experienced bakers who have produced quality snack cakes in the company’s bakeries for decades, Hostess management has chosen instead to hire primarily workers with little or no experience in the demanding wholesale snack cake baking industry.

“The B.C.T.G.M. has consistently stated our interest in working cooperatively and productively with the new owners of this company. We have always maintained that the experience, skill and professionalism of our members offer the new owners, who have no experience in the wholesale snack cake business, the best chance for long-term success in consistently putting out a quality product.”