Super frozen tuna adds to seafood mix

PUBLISHED : Wednesday, 08 September, 2010, 12:00am
UPDATED : Wednesday, 08 September, 2010, 12:00am

Sushi and sashimi-loving Hong Kong may pride itself in the freshness of its seafood but super frozen tuna, one of the freshest, is not even on the menu.

Billed as fresher than 'fresh' tuna, super frozen tuna could make it to local restaurants soon if suppliers find enough demand in the city. Fresh tuna is sold in Hong Kong, where countless supermarkets and restaurants cater to the public's voracious appetite for the delicacy.

Fukuichi Fisheries managing director Hiroshi Kondo said the Japanese supplier was looking at ways to export super frozen tuna to Hong Kong but needed to ensure the popular seafood product could be properly stored at minus 40 degrees Celsius. Most storage facilities in the city were only capable of temperatures of minus 20 degrees, he said at the inaugural Asian Seafood Exposition which runs until tomorrow at the Convention and Exhibition Centre.

'One possibility we are thinking about is building our own freezer here,' he said. 'Or we could try to convert some freezers from minus 20 degrees to minus 40 degrees.'

Sri Lankan supplier Global Sea Foods, which exports super frozen tuna mainly to Europe and the US, is also keen to tap the local market, according to business development manager Tilarni Amath. Unlike fresh tuna, super frozen tuna is flash frozen at minus 60 degrees Celsius or below immediately the tuna is caught, gutted and cleaned. It remains stored at very low temperatures until it is sold, unlike fresh tuna, which can be up to two weeks old before it is consumed.

The process of flash freezing at minus 60 degrees Celsius or below ensures freshness by preventing degradation by dehydration or bacteria growth. Reduced water loss helps prevent oxidation, which browns the flesh. Flash freezing delays the onset of rigor mortis, in which released chemicals stiffen flesh within hours of death. This means super frozen tuna maintains its deep red colour, and the taste and texture of freshly caught fish.