Dean Foods ( DF) said Monday that it will acquire the 87% stake in Horizon Organic Holding ( HCOW) that it doesn't already own for $216 million, or $24 a share.

The Dallas-based company also said it will take on $40 million in debt in the deal, which is expected to close during the fourth quarter.

Horizon Organic, based in Boulder, Colo., markets certified organic foods in the U.S. and certified organic milk in both the U.S. and the U.K.

In 2002, Horizon had revenue of about $187 million. The company's product line in the U.S. includes organic milk, a full line of organic dairy products and organic juices, pudding, fruit jels and eggs.

Shares of Horizon Organic spiked up 26% in early trading to $23.80 on the news. Shares of Dean Foods closed at $30.60 Friday on the New York Stock Exchange.