Whenever we want to work with DNA the very first step in any laboratory procedure is DNA extraction. Most procedures of DNA extraction exploit the fact that membranes of cells and of their organelles are composed of lipid walls that can be broken down using a detergent or an organic compound. The first step in most procedures is to break-up a tissue sample so that the cells are separated from each other as much as possible thereby exposing them to a detergent that dissolves the membranes. It is necessary to filter and wash the resulting mixture in a subsequent step to separate DNA from the remains of the cellular membranes and other cellular material. Finally, the DNA is precipitated in water for further use.
In the literature one can find literally hundreds of different protocols developed for different taxonomic groups, utilization, and budget. Very many are simple modifications of basic approaches. For instance, most DNA Barcoding protocols include long incubation steps with proteinase K, detergents, chaotropic chemicals, resins or organic extractions. Many of those take about a day, some are pretty toxic, or if you happen to use commercial extraction kits expenses are considerable.
A group of Italian researchers now developed a fast DNA extraction method without any purification step for both fresh and processed seafood, suitable for any PCR analysis. Their protocol allows the cheap and fast DNA amplification (as short as 30 min total)from any sample, including fresh, stored and processed seafood and from any waste of industrial fish processing, independently of the sample preservation method.
There are other fast methods out there but what makes this one compelling is the fact that the tests conducted were not only one with vertebrates, which is usually relatively simple, but also mollusks, which very often are challenging due to the presence of mucopolysaccharides and polyphenolic proteins which can interfere with subsequent PCR analysis. Worth a try I'd think.