NASA and its Canadian counterpart have held a competition for ideas on how to secure food for a long stay on Mars.

Contestants developed technologies to produce tasty and nutritious fare for long crewed missions.

Seven teams from universities and companies competed in the finals of the Deep Space Food Challenge at a university in the US state of Ohio on Friday.

A box-shaped device developed by the University of California and others uses electrolysis to convert water and carbon dioxide exhaled by humans into nutrients that can efficiently grow mushrooms and tomatoes.

A cylindrical oven built by a Colorado company enables safe heating even in zero gravity by using centrifugal forces from its fast-spinning cylinder. Powdered ingredients and water in the cylinder were turned into a hot pizza in about 20 minutes.

A woman who sampled it said she preferred it to a pizza that she could get at a takeout. She said she thinks the astronauts are "very lucky" as they can look forward to "a really good meal."

The winner was a team that came up with a system for raising vegetables and edible insects with automatic temperature and humidity control. They took home 750,000 dollars in prize money.

A NASA official said she was excited to see the innovative technologies. She said the goal is to provide astronauts with cuisine resembling what they would enjoy on Earth.