Fish fillets grow in tank

Scientists trying to create alternative food sources for astronauts believe we could grow meat on demand, without slaughtering fish or animals.

In a bid to make a simple source of nutritious food for long-distance space travellers, scientists at Touro College in New York have managed to make slices of fish grow bigger. Their achievement holds out the prospect of growing meat in industrial quantities from the muscle cell lines of various animals or fish.

"This could save you having to slaughter animals for food," says project leader Morris Benjaminson, a bioengineer and veteran of a number of NASA projects on recycling waste onboard spacecraft. But Benjaminson's initial aim is more modest.

He is working on more varied diets for astronauts, who would quickly tire of their bland freeze-dried or squeezy tubes of food on long missions to Mars, for example.

Artificial ecosystem

To make space meals more appetising, scientists have been looking at ways of producing fresh food for astronauts in flight. In 2001, German researchers designed an artificial ecosystem to provide a continuous supply of fresh fish in a spacecraft.

But breeding live animals for food has drawbacks - they produce excrement, and killing them generates a lot of waste too. So NASA is paying for Benjaminson to go one step further and grow just the animals' edible muscle.

Initial experiments to see if the idea could work were rather grisly. Benjaminson's group cut chunks of muscle five to 10 centimetres long from large goldfish. After washing the chunks in alcohol, they immersed them in a vat of fetal bovine serum, a nutrient-rich liquid extracted from the blood of unborn calves, which biologists usually use for growing cells in the lab.

After a week in the vat, the fish chunks had grown by 14 per cent, Benjaminson and his team found. To get some idea whether the new muscle tissue would make acceptable food, they washed it and gave it a quick dip in olive oil flavoured with lemon, garlic and pepper. Then they fried it and showed it to colleagues from other departments.

vCJD fear

"We wanted to make sure it'd pass for something you could buy in the supermarket," he says. The results look promising, on the surface at least. "They said it looked like fish and smelled like fish, but they didn't go as far as tasting it," says Benjaminson. They weren't allowed to in any case - Benjamison will first have to get approval from the US Food and Drug Administration.

Benjaminson concedes that people might be reluctant to eat food grown in fetal bovine serum - not least because of worries about the transmission of vCJD through any rogue prion proteins it may contain.

He tried growing chunks of goldfish muscle in liquid mushroom extract instead, but although the tissue survived for a week, it did not grow. He is hoping to find a friendlier substitute for bovine serum before trying the technique on chicken, beef and lamb.

The idea has received a cautious welcome. "Fish mass grown in a nutrient broth sounds as unappealing as some of the other food astronauts take up with them, but these things have got to be explored," says Colin Pillinger, head of the Planetary Space Sciences Research Institute at the Open University in Milton Keynes. "I think it'd be more appropriate when you've got a base set up on a planet - the sort of equipment you need for biotechnology is fragile. Who knows what would happen to it during launch and the flight," he says.

Ian Sample

British Psychological Society