NEW YORK (AP) _ The maker of Oreo cookies may again be the target for a shake-up as “Big Food” companies scramble to transform amid changing tastes.

Activist investor Bill Ackman’s Pershing Square said it took a 7.5 percent stake in snack maker Mondelez International Inc. that was worth about $5.5 billion. The disclosure comes as Mondelez, which also makes Ritz crackers, Cadbury chocolates and Trident gum, had already been slashing costs to offset weak growth.

Such cost-cutting has become common for major packaged food companies, which are up against volatile economic conditions overseas and shifting tastes that favor foods marketed as fresher or more natural. To appease investors, companies including Campbell Soup, Coca-Cola, General Mills, Kellogg and PepsiCo have said they would trim costs and free up more money for marketing, which is intended to drive up sales of their flagship brands.

The struggles have also led a flurry of corporate restructuring and deal-making that is reshaping the industry. That has included acquisitions of smaller, faster-growing companies, as well as consolidation among big players intended to further reduce costs by combining functions like manufacturing and distribution.

In March, H.J. Heinz Co. said it would buy Kraft Foods and create one of the world’s largest food and beverage companies. The early plans outlined by executives focused on the savings the deal would achieve, rather than the potential for sales growth. The deal was engineered by Heinz’ owners, Warren Buffett’s Berkshire Hathaway and the Brazilian investment firm 3G Capital, which has become known for its cost-cutting management style.

The creation of Kraft Heinz came after Monde