FSANZ today called for submissions on a proposal to clarify the permissions in the Food Standards Code on the use of carbon monoxide in fish.

FSANZ Chief Executive Officer Steve McCutcheon said the proposal sought to provide clarity on the appropriate use of gases on fish and would prohibit the use of carbon monoxide as a processing aid on fish such as tuna.

"FSANZ is aware of reports of some producers using carbon monoxide to maintain the red colour of the fish, which can hide the age of a fish," Mr McCutcheon said.

CO reacts irreversibly with the dark muscle tissue of tuna and similar fish, resulting in the fish becoming bright cherry red. CO prevents oxidation and discoloration, preserving the bright red tissue for an extended period of time, making it look fresher than it is.

"The Code currently permits CO as a general purpose processing aid but processing aids are not supposed to have any ongoing technological function.

"A number of regulators have asked FSANZ to clarify the Code to ensure CO is not used on fish."

The closing date for submissions on this proposal is 11 February 2013.