The commercialization of porgies or seabreams of the family Sparidae has greatly increased in the last decade, and some valuable species have become subject to seafood substitution. DNA regions currently used for fish species identification in fresh and processed products belong to the mitochondrial (mt) genes cytochrome b (Cytb), cytochrome c oxidase I (COI), 16S and 12S. However, these markers amplify for fragments with lower divergence within and between some species, failing to provide informative barcodes. We adopted comparative mitogenomics, through the analysis of complete mtDNA sequences, as a compatible approach toward studying new barcoding markers. The intent is to develop a specific and rapid assay for the identification of the common pandora Pagellus erythrinus, a sparid species frequently subject to fraudulent replacement. The genetic diversity analysis (Hamming distance, p-genetic distance, gene-by-gene sequence variability) between 16 sparid mtDNA genomes highlighted the discriminating potential of a 291 bp NAD2 gene fragment. A pair of species-specific primers were successfully designed and tested by end-point and real-time PCR, achieving amplification only in P. erythrinus among several fish species. The use of the NAD2 barcoding marker provides a rapid presence/absence method for the identification of P. erythrinus.

L. monocytogenes is a foodborne pathogen responsible for a serious disease with a high mortality rate, particularly in vulnerable consumers. Recently, the scientific community has shown increasing attention to the search for new natural molecules with antimicrobial activity, aimed at preventing the spread of foodborne diseases. Extremophilic microorganisms, typical of extreme temperature environments, are a valuable source of these molecules. The present work aimed to study the antibacterial activity of four pure compounds derived from a molecule, the pentadecanal, produced by the Antarctic bacterium Pseudoalteromonas haloplanktis, against two different pathotypes of L. monocytogenes. Growth assays were performed in 96-well polystyrene plates with serial dilutions of the tested compounds at different concentrations (0.6, 0.3, 0.15, 0.07 mg/mL). The plates were incubated at 37°C for 24 h, with a spectrophotometric reading at OD 600 nm. Preliminary results of this study showed that pentadecanal inhibits the growth of L. monocytogenes, with a MIC (Minimum Inhibitory Concentration) of 0.6 mg/mL. Acetal, carboxylic acid, and ester did not demonstrate antibacterial activity at the concentrations tested. These findings suggest the possibility of using pentadecanal as a natural antibacterial to improve safety standards along the food supply chain.

The increasing world market demand for seafood requires an expansion of product categories available to consumers. Inland fish are usually considered having unmarked taste and are less appreciated by consumers; thus, they have low commercial value. Therefore, the marketing of the lake’s fresh and processed fish is limited to the local market and consumers are currently uninformed and mistrustful about these species. In this study, six different fish species were caught in the Fondi lake (Lazio, central Italy): Anguilla anguilla, Tinca tinca, Carassius gibelio, Cyprinus carpio, Micropterus salmoides, Chelon ramada. All the samples were subjected to nutritional and DNA barcoding analysis. Moisture, protein, fat, carbohydrates, ash, and sodium content were measured. As regards the fatty acids profile, the most abundant were MUFAs with the highest value in Anguilla anguilla (45.97%). Oleic acid (C18: 1 n9 cis) was particularly high in Cyprinus carpio (55.46%). The fraction of polyunsaturated fatty acids (PUFA) revealed a higher DHA content (C22: 6 n3) in Anguilla anguilla than the other species (>12 %) while Chelon ramada presented both higher EPA content (C 20: 5 n3) and total fraction of omega 3 PUFAs. Concerning molecular analysis, a 655 bp fragment of cytochrome C oxidase subunit I (COI) gene was successfully used for the identification at the species level using both BOLD and BLAST public databases. The present study gives the basis for improving the knowledge and promoting inland fish’ market and traceability along the supply chain.