Mikio Atobe carefully peels a layer of rayon netting from a chunk of farmed bluefin tuna, revealing a secondary sheet of cloth clinging to its exposed flesh, partially yellowed by the mold coating it.

"Take a sniff," said the 43-year-old chief executive of Meat Epoch Co.

"You see, it doesn't emanate that distinctly fishy smell. Let this rest in the fridge for up to 20 days and you'll have quality aged tuna in around half the time it would normally take."