The chief said the loss of critical employees overseeing the nation’s food supply made his work impossible. Robert F. Kennedy Jr., the nation’s new health secretary, has pledged to gut the division.

Jim Jones, the head of the food division at the US Food and Drug Administration who oversaw the agency’s banning of the food dye Red No. 3 earlier this year, stepped down on Monday, citing widespread cuts across the agency that he said will make it hard to implement the types of changes the Trump administration is seeking,