Scientific justification of the shelf life of fish protein hydrolysate obtained using the enzyme protosubtilin G3x

Fish protein hydrolysate obtained by enzymatic hydrolysis from recycle fish materials using the enzyme protosubtilin G3x is a protein component in alternative microbiological culture media. The dried form of fish protein hydrolysate (FPH) is more preferable compared to the liquid one due to a longer shelf life, a more convenient method of storage and transportation. The shelf life of the culture medium is one of the main characteristics that the buyer of this product focuses on. The purpose of the work is to scientifically substantiate the shelf life of FPH, which will be used as a basis for the preparation of alternative culture media. Organoleptic, microbiological and physicochemical methods have been used to conduct the research. Three batches of experimental samples of FPH have been prepared and stored in hermetically sealed jars in a dark dry place at a certain temperature and humidity. A scheme for studying fish protein hydrolysate after a certain period of time has been developed taking into account the reserve factor. All batches of fish protein hydrolysate have been tested in accredited laboratories. The content of toxic elements in FPH is: lead – less than 1.0 mg/kg, cadmium – less than 0.2 mg/kg, arsenic – less than 5.0 mg/kg, mercury – 0.5 mg/kg. The sum of nitrosamines (NDMA and NDEA) is less than 0.003 mg/kg, polychlorinated biphenyls – less than 2.0 mg/kg. Pesticide analysis has revealed the presence of hexachlorocyclohexane (alpha-, beta-, gamma-isomers) in quantities of less than 0.02 mg/kg, DDT and its metabolites – less than 0.2 mg/kg. The radionuclides content does not exceed the permissible limit and is: cesium-137 – 4.3 ± 0.1 Bq/kg, strontium-90 – 3.9 ± 0.1 Bq/kg. Microbiological studies have established the absence of coliform bacteria, Staphylococcus aureus, pathogenic salmonella, as well as the absence of indicators of putrefactive spoilage (proteus, mold, yeast). The results of the studies have shown the possibility of storing fish protein hydrolysate for 4 years.