Shares of Dole Food Co. jumped 22 percent on Tuesday, as investors reacted to an unsolicited offer by its largest shareholder to take the company private.

David Murdock, who is chairman and chief executive of the Westlake Village fresh food and vegetable company and controls 40 percent of shares, offered $12 a share in cash during a meeting of the Dole board on Monday night, the company said. The offer values Dole at $1.5 billion, including debt.

The offer is an 18 percent premium above Monday’s closing price. Shareholders would receive $645 million in cash for their stock.

The 90-year-old Los Angeles billionaire, chief executive from 1985 to 2007 before temporarily stepping down, took the company private in 2003 after paying $33.50 a share in a deal valued at $2.5 billion. He then relisted Dole in a $1.1 billion second public offering in 2009.

In a statement, Dole’s board said it would meet to review the offer and that no decision had been made. Murdock also would assume all the company’s debts, which Bloomberg News reported totaled $440 million on a net basis. Murdock said he hoped to secure an agreement by the end of July.

Murdock told the board in a letter that taking the company private would allow it to focus on long-term goals “without the concern that a public company must have for the investing public’s short-term expectations,” according to Bloomberg News.

Dole has been hurt by a decline in prices for bananas and berries. Last month, it said that its full-year adjusted earnings before interest, taxes, depreciation and amortization would be $150 million, on the low end of guidance. Last year, its adjusted Ebitda was $172 million.

Murdock’s offer follows a deal that significantly downsized the company. In April, Dole completed the sale of its global packaged goods business and Asia fresh foods business to Itochu Corp., a Japanese firm, for $1.7 billion. The business accounted for about a third of revenue and half of profits.

But the company still remains the largest supplier of bananas, iceberg lettuce and cauliflower to North America. Founded in 1851 in Hawaii, it also supplies produce in 90 countries around the globe.

Murdock would appear to have plenty of cash to consummate the deal. Last year, he sold the Hawaiian island of Lanai for $500 million to Oracle chairman Larry Ellison.

Dole shares closed up $2.26, or 22 percent, to $12.46 on the Nasdaq.