Kayana Szymczak for The Boston Globe

Bertucci’s executive chef Jeff Tenner prepared fish samples being considered as replacements for fillets formerly used in the chain’s Baked Merluzzo.

Kayana Szymczak for The Boston Globe

Globe-sponsored DNA testing showed the dish contained hake instead of the cod described on the restaurants’ menus. Bertucci’s decided to replace the hake after the Globe informed it of the DNA test results.

Kayana Szymczak for The Boston Globe

The box shown here describes the fish Bertucci's formerly used in its Baked Merluzzo. It was hake, not the cod listed on the menu.

Kayana Szymczak for The Boston Globe

Bertucci’s chefs spent several weeks finding new suppliers for cod and trying out different samples of the fish.

Kayana Szymczak for The Boston Globe

Tenner, the executive chef, examined a cod sample being considered as a replacement for hake.

Kayana Szymczak for The Boston Globe

Among the fish being considered for Baked Merluzzo were a North Atlantic cod loin from Iceland and a Pacific cod fillet from Alaska.

Kayana Szymczak for The Boston Globe

Tenner presented all four fish – in raw and cooked versions -- to a panel of company executives for taste-testing.

Kayana Szymczak for The Boston Globe

Each prepared dish, carefully labeled, was wrapped in aluminum foil and placed in the 575-degree brick oven.

Kayana Szymczak for The Boston Globe

The tasting panel unanimously agreed that Pacific cod, from Boston’s North Coast Seafoods, was the best option. It is now being used in the Baked Merluzzo dish.