The move is part of the Reckitt Benckiser's plan to fund its £14.3bn purchase of U.S. baby food maker Mead Johnson Nutrition, agreed in February.
French's and Frank's RedHot will become McCormick's second- and third-largest brands, respectively, CEO Lawrence E. Kurzius said in a statement late Tuesday. The addition of Mead Johnson's infant and children's nutrition business is expected to increase Reckitt Benckiser's revenues in consumer health by approximately 90 percent and increase its developing market scale by approximately 65% percent. With 411 million pounds ($536 million) in sales previous year, French's Foods accounted for 4 percent of Reckitt's total revenue.
RB Food was "a strong complementary fit that we expect will strengthen McCormick's business opportunities as we expand our presence in condiments, a core category for the company in the United States and internationally", said McCormick boss Lawrence E. Kurzius in a separate statement.
The FTSE 100 gained 0.1 percent, with household goods and food sectors boosting the index while miners weighed.
The hot sauce category will continue to see robust growth, according to McCormick, and there are significant opportunities for expansion. McCormick predicts that, as a combined entity, pro forma net sales are set to reach $5 billion. The company went after another United Kingdom business in 2016, when it considered buying Premier Foods.
With the acquisition of Reckitt Benckiser's food division, McCormick is adding a roster of brands to its spice and seasoning mix portfolio that further strengthens the company's position as a go-to destination for adding flavor to a variety of dishes.
The market reaction suggests that investors think McCormick may have paid too-high a price.
Credit Suisse Group is serving as the financial adviser to McCormick on the RB Foods transaction, and Cleary Gottlieb Steen & Hamilton is legal counsel.
The BBC says the sale will "pay off debt" taken on to complete the Mead Johnson deal.
RB and McCormick expect the deal to close in the autumn, subject to regulatory approvals.