PORTLAND — The owner of an Amato’s is suing the federal government about losing its eligibility to participate in the food-stamp program, saying the action will cost the business as much as $30,000 per year.

Steven Roderick, the owner and operator of Amato’s of Norway, contends that the decision by U.S. Department of Agriculture Food and Nutrition Services was made arbitrarily. He filed his suit in U.S. District Court on Monday.

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The central issue of the case appears to be whether Amato’s – best known for a type of submarine sandwich known as “Italians” – is a food retailer or restaurant. The chain got its start in Portland and now has locations in Maine, New Hampshire, Vermont and New York.

According to the complaint, Roderick applied to participate in the Supplemental Nutrition Assistance Program as a food retailer in 2009. An inspector visited the business in October. Roderick was notified in March that his eligibility was being withdrawn because the business operated primarily as a restaurant.

Roderick had the decision reviewed and provided photographs to show that the business carried products required by the food-stamps program. The final agency decision stated that it wasn’t clear that the Norway Amato’s was primarily a restaurant but it upheld the suspension on other grounds, according to the complaint.

Dana Hanley, Roderick’s lawyer, said it was not exactly clear why the decision was made. He said he hopes it will become evident as the case moves through the discovery process.

Roderick declined to comment on the case.

SNAP benefits can be used for items like bread, produce, meat and dairy products. They cannot be used for hot foods or foods to be eaten inside the store.

Amato’s menu includes hot and cold sandwiches, pizza, pastas and salads. It also has catering services and sells a line of sauces.