Innovative molecular techniques to be applied on seafood identification, specifically NGS based techniques

Food fraud has increasingly diffused due to the globalization and complexity of modern supply chains. Mislabeling - meaning false claims or distortion of the information reported on the label - is currentlythe preponderant form of food fraud. Seafood is among the commodities at high risk of mislabelling. The most common is the substitution of high-value with less expensive species or farmed versus wild sourcing, the selling of fish from illegal fishing, and the recycling of by-catches or fish waste. Potential consequences involve economic losses, ecological impact, undermining of sustainability efforts, mining religious or ethical reasons. In addition, the illicit presence of toxic species or the omission of ingredients potentially causing allergies (e. g. crustaceans or molluscs) may lead to human health risks. Food authentication, being the process that verifies that a food matches its label description, is of great interest from a commercial, health and a legal point of view. Among the available methods, those based on DNA analysis continue to have a major place, and their use is also encouraged by EU legislation to deter operators from falsely labelling practices in the fishery sector. DNA barcoding has become a key player in maintaining the high-quality of foodstuff. Despite its advantages, the efficiency of the DNA barcoding is limited by the number of target species that can be simultaneously identified. In fact, it relies on Sanger sequencing – also known as first generation sequencing – a low-throughput method that produces partial output, showing only the dominant species and failing to identify the others. Therefore, the method can be critical when processed and complex foods potentially consisting of multiple species are tested. This aspect might be particularly felt by FBOs since complex seafood products have currently won a large market share, following the diet habits of consumers that are increasingly addressed to ready-to-eat/ready-to-cook products. The Next Generation Sequencing (NGS) technologies are high throughput methods able to simultaneously sequence all the DNA molecules, including those present in trace amounts. Differently to Sanger sequencing, where a single amplicon from a single species is amplified and a unique sequence is obtained, in this case 100% of the DNA contained in a sample can be hypothetically amplified and sequenced each time, they are the most promising analytical tool for complex food authentication. However, differently from other investigation fields, its application in foodstuff is limited, mainly due to the lack of standardized protocols from the sampling to results interpretation. We performed a systematic review to answering the question “Is the metabarcoding ready to be applied to the authentication of foodstuff of animal origin?” and we observed that only 23 studies on this topic are available. Most of them did not apply proper quality control measures to prevent and avoid contamination that can distort the final data. Further investigation should be performed in order to define Standard Operating Procedures (SOPs) and harmonize protocols.