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Australian Government: National Measurement InstituteAustralian Government: National Measurement Institute
National Measurement Institute

Carbon Monoxide in Fish

red fish filletsIt has been reported that some processors are using carbon monoxide during fish processing. Carbon monoxide treatment is used for colour preservation typically where the red colour is an important quality attribute for consumers. It is most commonly used for tuna, but similar fish such as mahi-mahi and tilapia are also treated.

Carbon monoxide treatment results in the formation of carboxymyoglobin in fish flesh which alters or fixes the colour of the fish. Carboxymyoglobin is relatively stable during frozen storage and through bacterial spoilage. It can last beyond the actual shelf-life of the fish.

As a change in colour is used by many consumers as a primary assessment of quality, carbon monoxide treatment has the potential to make inferior quality fish appear aesthetically more pleasing to consumers or to mask decomposition resulting in an increased risk of histamine fish poisoning. It has been reported that histamine can reach high levels in carbon monoxide treated tuna despite the colour of the fish remaining acceptable.

Food Standards Australia New Zealand has assessed the Australia New Zealand Food Standards Code to ensure it does not permit the use of carbon monoxide in the processing of fish and has approved a variation to Standard 1.3.3 – Processing Aids. The variation clarifies that carbon monoxide must not be used where its use results in a change to, or fixes the colour of, the flesh of the fish. The variation also clarifies that this prohibition does not extend to carbon monoxide that is naturally occurring or naturally present in smoke being used to process fish as a food.

NMI's Capabilities

We have developed a sensitive and highly selective method (NR60) for the determination of carbon monoxide in fish.

Our sampling requirements and limits of reporting are shown below.

Sample (g)​ Preservation​ Analyte​ Limits of reporting​ NATA accreditation​
50​ Freeze (<0 ºC)​ carbon monoxide (CO)​ 100 μg/kg​ a​ccredited​


For further information please contact, 1300 722 845 or use our on-line form.