Is Farmer Bros. Co. fattening up on a steady diet of Egg McMuffins?

The Torrance coffee company started supplying coffee to McDonald’s Corp. in October, said one analyst, who added that the Oak Brook, Ill., fast-food giant is now Farmer Bros.’ biggest single customer.

Between that development and the company’s long-awaited return to profitability, Farmer Bros.’ shares have picked up nearly 25 percent since its Nov. 5 earnings announcement.

Shares ticked up last week nearly 15 percent to close at $12.83, making it the top gainer on the LABJ Stock Index for the week ended Dec. 12. (See page 30.)

Farmer Bros. had been unprofitable for several years due to a shrinking list of customers and rising coffee bean prices. But under Michael Keown, who took over as chief executive in March, the company has added accounts, including Deerfield, Ill., drugstore chain Walgreens Co.; Salisbury, N.C., grocery chain Food Lion LLC; and McDonald’s. The company also has added higher-end products, increased unit sales and benefited from falling bean prices.

The company last month reported its first profitable quarter since December 2009, with net income of $2.9 million, or 19 cents a share, for its first quarter ended Sept. 30. Anton Brenner, an analyst who follows Farmer Bros. for Roth Capital Partners LLC in Newport Beach, expects the company to keep making money and estimates earnings of 65 cents a share for the fiscal year.

So bullish is Brenner, one of only two analysts who follow the company, that he recommended investors increase their holdings in Farmer Bros. after a Nov. 29 announcement that the company’s chief financial officer had resigned.

“We would use any price weakness from this development to accumulate positions in the stock,” he wrote in a Nov. 30 memo. “We look for a strong earnings rebound over the next several years.”

Representatives at F. Gaviña & Sons Inc., a Vernon coffee roaster that has been a supplier to McDonald’s in Southern California since 1985, did not return calls for comment.

Neither did McDonald’s and Farmer Bros. executives. Neither company has announced they are working with the other.

Brenner, who mentioned in a Nov. 6 research note that Farmer Bros. had started shipping to McDonald’s, said the deal is “generally known in the industry.”