Application of a portable near-infrared spectroscopic device for on-field monitoring of the country of origin labelling of musky octopus

Today, cephalopods are of increasing economic and nutritional importance, as highlighted by the increasing global productions which reached over 365 million tons in 2018 [1]. Among cephalopods, large scale production and distribution of musky octopus (Eledone spp.) originating from the Mediterranean and North-East Atlantic fishing areas are currently increasing, thus potentially questioning the truthfulness of the geographic indications reported on the label and, by consequence, qualities and reputation that are due to the specific origin. As a matter of fact, fraudulent mislabelling concerning the country of origin is becoming a pressing problem affecting the fishery sector both from an economic and a sanitary point of view. Hence, a growing need exists for tightening up fish controls on the one hand and shifting towards a risk-based control of seafood provenance on the other, through the implementation of efficient and standardised food inspection analytical tools, for which the requirements of rapidity, portability, cost-effectiveness, and easiness of application are met. In the present study, the objective was to verify the suitability of using a handheld and portable near infrared (NIR) spectrometer to characterize the geographic origin of musky octopuses in a non-destructive and simple way. Three different batches of frozen musky octopuses (Eledone spp.) of medium size were collected from each of the two sampling sites chosen, corresponding to the FAO fishing areas 37.1.1 (i.e., Mediterranean Sea) and 27.9.a (i.e., North-East Atlantic Ocean), for a total of 118 specimens. After defrosting, cleaning, and skinning, 4 replicate NIR spectra were acquired from four different area of the samples’ mantle using the portable NIR device MicroNIR OnSite-W by VIAVI (VIAVI Solutions Inc., San Jose, CA, USA). The instrumental parameters and analytical conditions were set as follows: diffuse reflectance acquisition mode, 908–1676 nm wavelength range, 6.2 nm resolution, 50 spectral scans, 10 ms integration time. The spectral data were exported and elaborated by chemometrics using the SIMCA 16.0.2 software package (Sartorius Stedim Data Analytics AB, Umea, Sweden) to generate a qualitative model based on orthogonal partial least square discriminant analysis (OPLS-DA) to differentiate samples according to their origin. The OPLS-DA calibration model from NIR spectral data, created using 70 out of 118 octopus’s specimens, showed excellent prediction statistics outcomes, with an estimate of the fit and the prediction ability of the model reaching 86% and 78%, respectively. In addition, when the accuracy of the model in recognizing the remaining unlabeled 48 octopuses was tested, it was found that 90% of the Mediterranean samples and 89% of the Atlantic samples were correctly identified. By way of conclusion, the results achieved clearly highlight the effective support provided by NIR spectroscopy in the early detection of fraud related to the seafood origin. In the near future, the shift towards miniaturization and portability of the analytical instrumentation, may therefore result in fish authenticity testing moving directly to the field, being particularly advantageous in the context of daily routine and screening analysis both at industrial and retail level.