Northern bonito or albacore, Thunnus alalunga. (Photo: filaman.ifm-geomar.de)
Northern bonito labeling fraud found out
Friday, July 11, 2014, 00:50 (GMT + 9)
A team of researchers from the CEU San Pablo University proved the existence of fraud because of the substitution of northern bonito or albacore tuna (Thunnus alalunga) with species of lower commercial value.
With the help of an immunoenzymatic technique known as ELISA, the scientists determined that yellowfin tuna (Thunnus albacares), little tunny (Euthynnus alletteratus), bullet tuna (Auxis rochei), skipjack (Katsuwonus pelamis), bigeye (Thunnus obesus) and bonito (Sarda sarda) are being sold with albacore tuna label.
This alternative method to DNA testing is more effective for authentication of fishery resources for its specificity, simplicity and sensitivity.
Under the direction of Esther Carrera, professor of the Department of Pharmaceutical Sciences and Health of CEU San Pablo University, professors of the Complutense University of Madrid also participated in the study.
The researchers obtained polyclonal antibodies, which then used to identify the albacore and differentiate it from other species of scombroid that have lower commercial value.
The team analyzed 40 filleted samples (20 fresh ones and 20 frozen ones), all of which had been labelled and sold as northern bonito coming from local markets and supermarkets in Madrid. And it determined that 32.5 per cent of total samples showed no reactivity, implying that these fish were not really albacore.
The rest of the analysed samples (67.5 per cent) should be subjected to a DNA analysis as discriminatory technique to differentiate between albacore and yellowfin tuna because the polyclonal antibodies obtained did not allow differentiation.
Experts also found that all incorrectly labelled samples corresponded to frozen fish.
The results of this study indicate that despite the strict control measures adopted by the European Union (EU), the fraud is occurring.
Carrera argues that these findings are very important to improve the labeling control of albacore and protect consumers’ health.
- Up to 25pc of tuna products mislabelled
By Analia Murias