Reser’s Fine Foods is making mashed potatoes and preparing to add capacity to produce more dishes at its new food processing plant in Pasco.

The family-owned company showed off its new $120 million plant at 5526 N. Capitol Ave. in September.

The plant began operating earlier in the summer but shut down for the opening festivities so local officials and the media could tour the production areas, where it transforms Washington-grown potatoes into deli dishes.

Even as its president, Mark Reser, and other officials cut the ceremonial ribbon, construction crews were working to frame an addition on its west side. The plant will have a 340,000-square-foot footprint when the addition wraps up.

The extension will allow it to add lines to produce the potato salads and macaroni salads that anchor its line of grocery case staples. It will add ovens for its baked products and seasonal deli salads.

The new plant is more than double the size of Reser’s former quarters at the Pasco Processing Center, which opened in 1998.

Mark Reser, grandson of founders Mildred and Earl Reser, said the Portland-area company could have expanded anywhere. The upper Midwest was a strong choice from the point of view of serving East Coast customers.

But Pasco offered a compelling case for building on a facility that has been a strong performer since it started.

The region has the best potatoes, tradespeople and workers.

“Our decision was easily made,” he said.

The company initially intended to remodel its former plant but has revised its plans. The 110,000-square-foot building, 5310 Industrial Way, is for sale with an asking price of $15 million.

Kirt Shaffer of Tippett Co. in Pasco is the listing broker.

All its workers are now stationed in the new plant. A spokesperson said it will add 100-plus jobs by mid-2023, once all renovations are complete.

The plant operates three shifts per day, two for production and one for cleaning.

Reser’s was one of four companies that announced big investments in Pasco in 2021. It is the first to complete the challenge it set for itself.

A pair of warehouse distribution centers serving Amazon Inc. is nearly complete but has not yet opened.

The other two, Darigold Inc. and Local Bounti Inc., both took significant steps in September to develop their projects. Seattle-based Darigold broke ground on its $600 million milk-processing plant in north Pasco and Local Bounti of Hamilton, Montana, resumed work to prepare its east Pasco site for a future greenhouse complex.

“There is a lot going on in Pasco right now,” said Pasco City Manager David Zabell, who attended the ribbon cutting. He retires at the end of October.

Reser’s employs 4,000 at 14 facilities in eight locations in the U.S. and Mexico. It does not disclose revenue, but in 2009 it said it was approaching $1 billion.