Exhibit 15.1

November 5, 2020

To the Board of Directors and Stockholders of

TreeHouse Foods, Inc.

2021 Spring Road

Suite 600

Oak Brook, Illinois 60523

We are aware that our report dated November 5, 2020, on our review of the interim financial information of TreeHouse Foods, Inc. appearing in this Quarterly Report on Form 10-Q for the quarter ended September 30, 2020, is incorporated by reference in Registration Statement Nos. 333-231122, 333-223899, 333-206161, 333-183321, 333-150053, and 333-126161 on Form S-8 and Registration Statement No. 333-248399 on Form S-3.

/s/ DELOITTE & TOUCHE LLP

Chicago, Illinois