Billionaire investor Ron Burkle is working with a union representing workers at Dow Jones & Co. to explore alternatives to Rupert Murdoch’s $5 billion bid for the company, which publishes the Wall Street Journal.

The Independent Association of Publishers’ Employees said in a statement yesterday that it had reached out to Mr. Burkle, as well as the billionaire investor Warren Buffett and others, in an attempt to find other potential buyers for Dow Jones. The union strongly opposes Mr. Murdoch’s bid, saying he might slant the Journal’s coverage to suit his business interests.

Mr. Burkle, who made a fortune investing in supermarket chains, lost out on a joint bid for Tribune Co. with fellow investor Eli Broad, and also worked with newspaper unions on failed bids for Knight Ridder Inc. and for the Philadelphia Inquirer and Philadelphia Daily News.

After initially rebuffing Mr. Murdoch’s offer in early May, Dow Jones’s controlling shareholders, the Bancroft family, held an initial meeting with Mr. Murdoch and several of his senior executives Monday to discuss his interest in Dow Jones. IAPE, which represents about a quarter of Dow Jones employees, said it hoped the Bancrofts would decide not to sell the company, but that if they did, that they would consider alternatives to Mr. Murdoch.