Two large school districts that are switching to environmentally friendly plates in their lunchrooms will boost production at a Maine compostable plate manufacturer by 10 percent.

Huhtamaki, a Finland-based food and beverage package maker with factories in Waterville and Lewiston, will make 19 million more compostable round plates annually to supply the Philadelphia and Baltimore public school districts, which are eliminating polystyrene plates.

Urban School Food Alliance, a nonprofit coalition of the largest school districts in the United States, announced the deal Monday on behalf of the schools with Huhtamaki’s Waterville factory.

The alliance, which also includes the New York, Los Angeles, Chicago, Boston and other school districts, buys food and supplies for member districts to leverage purchasing power and improve food quality and environmental practices.

“As one of the smaller [school] districts in the alliance, we couldn’t have afforded to purchase compostable plates on our own,” Wayne Grasela, senior vice president of food services at Philadelphia’s school district, said in a prepared statement.

The alliance noted that polystyrene plates cost about 4 cents each compared to 12 cents for a compostable plate. The alliance’s group buying power dropped that to 5 cents a compostable plate.

The alliance buys 225 million plates a year from Huhtamaki, its only supplier. The two new school districts will increase that to 244 million, said Huhtamaki spokesman Wess Hudelson, who works out of the company’s U.S. headquarters in De Soto, Kansas.

Huhtamaki also has five employees in Lewiston who make PET plastic film for other products at the Waterville plant.

Hudelson said the new order won’t result in more hiring at the Waterville factory, but it is a “good increase in a product line that has had steady growth.”

The plates, made of molded fiber, filled a hole in Huhtamaki’s orders in 2016, when an E. coli outbreak at Chipotle caused that restaurant chain to cancel orders of fiber bowls. Some 25 Huhtamaki employees were temporarily laid off.

The Waterville factory has seen employment grow steadily since then, from 470 people in January 2016 to 503 now.

“We’ve seen steady growth in a number of products, including the round plates,” Hudelson said. “The round plate helped offset our losses from Chipotle plus grow a bit.”

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