Citizen science approach for genetic species identification in a local French seafood speciality

Abstract

In coastal regions of France, seafood is a key element of traditional cuisine and is valued by consumers as quality food. However, in the last decades, the mislabelling of food products has undermined consumers' confidence in their food choices. In this study, we used genetic identification of the seafood species used to prepare a traditional dish of the city of Sète, to initiate a discussion on food labelling and sustainability. The dish, named “Tielle sétoise", is a pie traditionally filled with octopus cooked in a spicy tomato sauce. The recent substitution of octopus by jumbo flying squid (Dosidicus gigas) has triggered debates among locals about how the use of non-native cephalopod species impacts the flavour of tielles. To test this hypothesis, we coordinated a tasting event involving 35 testers from the local population and used CO1-gene metabarcoding to identify the species composition in 25 different tielles. Besides locally available octopuses’ species, including common commercial species Eledone cirrhosa, E. moschata and Octopus vulgaris, we found jumbo flying squid in 17 out of 25 tielles, of which eight (35%) were mislabelled as octopus-based products. Contrary to local belief, anonymous blind-tasting evaluations showed no significant correlation between the flavour or price of a tielle and the cephalopod composition of its filling. Our results support the impact of texture, acidity, and spices on flavour, suggesting that flavour depends more on how tielles are prepared than on the cephalopod species used. The participants in our study expressed their willingness to make informed choices about purchasing tielles based on the carbon footprint and its impact on cephalopod stocks. Our results call for further research to enable citizens to make informed food choices. Our study also highlights the need for improved labelling of traded cephalopods to improve communication between the food industry and society, as well as the possibility of evaluating this with citizen science.