The Stouffer's frozen line showed positive signs during the first quarter.

VEVEY, SWITZERLAND — Executives at Nestle S.A. have been upfront in recent months about the challenges facing the Vevey-based company, particularly in the frozen food category, and especially in the United States. How the company is addressing those challenges again came to the fore in a first-quarter corporate sales call on April 17.

During the call, Steffen Kindler, head of investor relations at Nestle, said the company’s U.S. frozen business has experienced “modest” improvement recently. While Lean Cuisine and the frozen pizza business have remained challenged, the Stouffer’s line showed positive signs during the first quarter.

“It’s not an overnight fix,” Mr. Kindler said of the U.S. frozen business. “We are committed to fix the business. And we believe frozen remains relevant to the consumer. Just to remind, frozen is a sizeable category. And it’s important for us as well as for the retailers with the assets that have been invested into that category.”

Nestle has a number of leading positions within frozen, and Mr. Kindler said the company is identifying all areas of the marketing mix that may play a role in spurring growth.

“We’re making our product more relevant to the consumer,” he said. “We’re changing the product, the ingredients. We’re changing the packets. We’re changing the communications. So we’re really addressing all elements of the marketing mix.”

Even though new processes have been put in place, Mr. Kindler cautioned that it is still too early to say whether the new measures have had a significant impact on results.

“We’re launching, for example, for Lean Cuisine, that the products are hitting the shelves as we’re speaking,” he said. “So we’re going to see the effect of that probably towards the middle of the year and especially in the second half.”

Nestle had sales of 20,918 million Swiss francs ($21,963 million) in the first quarter of fiscal 2015, up from 20,822 million Swiss francs in the same period a year ago.