By the narrowest of margins, Dole Food Co. stockholders on Thursday approved the sale of the company to its 90-year-old chairman and chief executive. Less than 51 percent of stockholders not associated with David Murdock and his affiliates approved the deal to take the produce company private. A special meeting was held at the company’s Westlake Village headquarters. Murdock, who controlled 40 percent of the stock, offered $13.50 a share to buy the company, nearly a third more than an initial $12 a share offer in June. The offer values the company at roughly $1.6 billion, including debt. Both Institutional Shareholder Services and Glass Lewis & Co. LLC, proxy firms that advise investors, gave their stamp of approval to the offer. A total of 27.5 million shares not affiliated with Murdock were voted in favor of the sale. Dole will now operate as wholly owned subsidiary of DFC Holdings, controlled by Murdock. The Los Angeles billionaire took the company private once before 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 initial public offering in 2009. Dole is now a significantly smaller company after selling off its global packaged goods business and Asia fresh foods business to a Japanese firm for $1.7 billion in April. The business accounted for about a third of revenue and half of profits. The merger is expected to close on or about Nov. 1, after which the company will be delisted from the New York Stock Exchange. Shares closed up 2 cents, or a fraction of a percent, to $13.56.