Authentication of processed Philippine sardine products using Hotshot DNA extraction and minibarcode amplification

Abstract

In lieu of the importance of species authentication of processed fishery products, no reports have been made on sardine products in the Philippines. This is partly because of the challenges in dealing with biological material that has been subjected to extreme conditions during the process. Although molecular tools are now within reach, they are often reliant on proprietary kits which make the process expensive. In this paper, we used hot sodium hydroxide and tris (HotSHOT) DNA extraction protocol and cytochrome oxidase I (COI) minibarcode amplification to genotype and identify selected brands of locally-produced canned and dried sardines. To validate, fresh representatives based on advertised and suspected identities of the processed samples were genotyped as well. Success rate of amplification has gone from 0% to 64% when the minibarcode was amplified, as opposed to using the full-length COI barcoding region. Phylogenetic analysis allowed for the successful identification of processed Sardinella lemuru. Species substitution was detected on samples marketed as dried tawilis; however, the resolving power of minibarcode was not enough to discriminate the samples up to the species level. Regardless, coupling HotSHOT extraction with minibarcode amplification proved to be effective with processed sardines. Using this method to authenticate other processed fishery products that have underwent extreme postharvest processing warrants further exploration.