MORTON GROVE, ILL. — Lifeway Foods, Inc. has rejected Danone SA’s unsolicited offer to acquire the kefir maker for approximately $283 million. Danone is currently a minority shareholder in the business.

Lifeway Foods said its board of directors determined the offer undervalued the company and was not in the best interest of the company and its shareholders.

Out of concern that Danone may try to gain control of Lifeway Foods by buying additional company shares on the open market, Lifeway’s board also has adopted a limited shareholder rights plan. The plan is “intended to enable all shareholders to realize the full value of their investment,” according to the company.

Lifeway’s board added that the rights plan does not prevent other offers to acquire the company.

On Sept. 23, Danone offered $25 per share in cash to Lifeway Foods, which implied a premium of 59% over Lifeway’s three-month volume weighted average price, according to a filing with the US Securities and Exchange Commission. The offer equated to about $283.4 million, based on 11.34 million shares of common stock outstanding as of Aug. 6.