Tradizione e innovazione nell’analisi delle impurità e degli infestanti degli alimenti: dal filth test al dna barcoding alla metagenomica

The quality assessment of foodstuffs is an important tool for agri-food industries: contaminated products can not be sold in the market because of sanitary problems and potential health risks for the consumers. Today, different techniques are available for the detection and identification of food contaminants. Macro-contaminations can be directly detected, whilst micro-contaminations can be discovered with filth test analyses; also, a molecular approach is possible and it is called ‘DNA barcoding’. Filth-test is a well-known method which allows the detection of arthropod fragments, hairs or other kind of solid impurities. After their finding, the final evaluation represents the most critical part, because great expertise is required to reveal their nature. This is important not only to assess the foodstuff quality, but also to infer information about the source or place of contamination in the production chain. DNA barcoding represents an alternative and useful approach for the identification of biological samples showing particular features (size, conservation or lack of diagnostic parts missed during foodstuff processing) that do not allow the use of traditional identification methods. It is based on the analysis of short and standardized fragments of genomic DNA, thanks to the development of the sequencing technologies and the availability of free on-line databases of previously characterized DNA sequences. In the last years, further advances have been made with the “metabarcoding”, a novel approach which combines the DNA barcode-base identification system together with the high-throughput ability of the next-generation sequencing (NGS) techniques. This method can be used to reveal the whole content of complex substrates like water, soil or foodstuff like flour and its derivatives, and it will be further investigated in the future for foodstuff analysis.