-  Fish species identification after its processing leads to difficulty because of the loss of morphological characteristics. Good quality and quantity of DNA is the first step for molecular based fish identification. In present study, five out of nineteen DNA extraction methods were shortlisted after employing on non-marinated fried fish nuggets. For analyzing the effects of differently processed and fried fish on DNA extraction, raw and samples cooked at 170-180 ⁰C for 5 minutes in different oils with a freezing (at -20 ⁰C) interval were subjected to five DNA extracting techniques. Addition of marinating ingredients of fish products adversely affected both the DNA quality and quantity. Overall, the control (non-marinated and non-fried) nugget of Labeo rohita (rohu) yielded the highest DNA (14988 ng/µl) whereas NMMO (marinated and fried in mustard oil) yielded the lowest (9011 ng/µl) value, with a little difference in their purity ratio (260/280) being 1.75 highest for control and 1.62 for NMCO (nuggets marinated and cooked in cooking oil). A significant difference (P<0.001) in DNA yield was found for applying different marinades and oils for cooking while in purity significant difference was found only for different oils. A significant difference (P<0.001) in the DNA content was recorded before and after the freezing interval manifesting a decreasing trend for frozen samples. SNET extraction method proved to be best in terms of yield whereas the salt out method gave the highest purity with respective values of 16177 ng/µl and 1.77 respectively. These findings permit to design a powerful tool for thermally treated processed fish’ forensics.

Index Terms: DNA extraction from fish, DNA extraction from processed fish, DNA extraction from cooked fish, Fish Identification, DNA degradation, Species fraud