3M is based in St. Paul, Minn., and sells everything from Post-it Notes to Nexcare bandages and N95 masks. The food-safety business is part of its healthcare business, one of its four major units.

The deal is structured as a Reverse Morris Trust, a tax-efficient way for companies to sell off a division, with Neogen’s management team running the combined company. It values the 3M unit at $5.3 billion. Existing 3M shareholders will own 50.1% of the combined company.

Many of 3M’s industrial conglomerate peers such as

General Electric Co.

and

Emerson Electric Co.

have been splitting up or shedding assets in response to investor demand for focused companies.

Neogen offers test kits and other products to help track sanitation and allergens everywhere in the food-supply chain from “the farm gate to the dinner plate.”

Neogen’s chief executive officer,

John Adent,

who will lead the combined company, said in an interview that talks about the deal stretch back to 2019. He said it would create a more efficient food-safety company with a balance sheet primed for future deals. “It gives us the scale we need,” he said.

He said the company will be poised to benefit from an increased demand for food-safety products as consumers get more interested about what’s in their food.

The deal would expand Neogen’s product offerings and its research and development capabilities, the companies said. The combination would make Neogen’s food-safety segment about 70% of its total revenue, and the combined company would have projected sales of about $1 billion in the first full year post-closing.

Write to Cara Lombardo at cara.lombardo@wsj.com and Patrick Thomas at Patrick.Thomas@wsj.com