The aim of the work is to develop a technique for Express determination of trout falsification by the method of heat treatment by differentiating its thermal state: “chilled” - “frozen” with the use of a synchronous thermal analysis device. The device of the synchronous thermal analysis STA 449 F3, Jupiter, made by NETZSCH was used for experiments. The trout samples were examined in a copper furnace with the connection of a Dewar’s vessel in oxidized aluminum crucibles in helium atmosphere, while simultaneously fixing differential scanning calorimetry (DSC) curves and and the weight loss (WL) curves. The developed methodology includes recommendations for the selection of a trout sample for analysis; the DSC temperature program for monitoring fish processing and storage, the conditions for obtaining a DSC curve for the reference sample; a criterion for the thermal state of the experimental sample of trout. The DSC temperature program provides for sequential two-fold freezing operations - heating of a sample of trout muscle tissue from its spine mass of 24 mg in the temperature range from 25 to minus 30 ° C by cooling with nitrogen at a speed of 5 K/min. The exothermic effect of the second freezing for the reference sample serves as a criterion for the thermal state of the experimental trout sample.