Kellogg said it would buy palm oil only from companies that do not destroy tropical rain forests to produce the additive, which is used in many processed foods. Palm oil cultivation has wiped out more than 30,000 square miles of rain forests in Indonesia and Malaysia alone. Kellogg announced last week it would require its suppliers to trace their palm oil to plantations that have been verified independently as meeting standards for protecting the environment and human rights. Palm oil is a minor ingredient in Kellogg products such as Pop-Tarts, cookies and waffles, although most of its cereals do not contain it. Palm oil generates $50 billion annually, according to Green Century Capital Management.