Volumes fell 5.1% in the three months to the end of November, the world's largest chocolate maker said, as it was hit by lower output at its biggest factory.
The declines occurred as the Swiss company started ramping up production again at its Wieze factory in Belgium, which was hit by a salmonella scare last year.
Significant de-stocking and food manufacturers delaying orders also contributed to the decline in volume.
Sales revenue increased by 3.8% to 2.1 billion Swiss francs ($2.28 billion), as the company passed on raw material price increases the company said.
In local currencies, revenues increased by 7.2%.
"A number of reasons have led to a slow start to the year by Barry Callebaut standards, but a significant acceleration is expected in the course of the year," said Zurcher Kantonalbank analyst Daniel Burki.
Peter Boone, chief executive said that the chocolate maker was on track to achieve its existing targets.
"We are committed to achieve our current three-year mid-term guidance in this final year, based on our broad product portfolio and broad geographic and customer base," he said in a statement.
Barry Callebaut also announced a new mid-term guidance of 4%-6% volume growth for the years 2023 - 2026, slightly down from the current 5%-7% targeted volume growth for the three years up to 2023.
"We had expected coming out of COVID an acceleration," Boone said. "The acceleration is back to a normal trajectory."
Barry Callebaut also said it would target 8%-10% EBIT growth in local currencies for the period 2023-2026.