Establishing the safety and quality of fish and fish products using unique methods

Abstract

Food business operators involved in the farming, storage, and sale of fish and the production of fish products must implement traceability systems and food safety assurance systems to enable risk-based control throughout the entire production cycle – from fish harvesting and processing to storage and retail. For the effective work of state veterinary inspectors during risk-based control at fish production and distribution facilities, it is recommended to implement the developed unique express and optimized methods for monitoring fish and fish products. These methods help establish quality and safety indicators and ensure compliance with shelf-life requirements through adherence to sanitary and hygienic standards at fish production and distribution sites. The recommended methods include: the peroxidase reaction, a photometric method for assessing fish freshness, bacterioscopic determination of the freshness of fish and fish products, measurement of the moisture-holding capacity of fish meat and fish products, and determination of histamine and sodium chloride content in fish products. These methods demonstrated a diagnostic accuracy of 99.3 %–99.9 % in testing. Research enabled the differentiation of chilled and frozen fish by assessing freshness using the peroxidase reaction: Fresh fish showed a blue-green color; Fish of doubtful freshness showed a light blue color; Spoiled fish showed an absence of blue-green coloration. Optimal optical density values of meat-water extracts with Nessler’s reagent were identified: Up to 0.245 units (B) – fresh fish and fish products (light yellow color), From 0.246 to 0.545 B – fish and fish products of doubtful freshness (intense yellow color), From 0.546 to 0.845 B – spoiled fish and fish products (orange color). Using the unique express bacterioscopic method, the degree of freshness of fish and fish products was determined by counting the number of microorganisms in five visual fields on a single impression smear from the fish or fish product: Fresh – up to 10 microorganisms, Doubtful freshness – 11 to 30 microorganisms, Spoiled – more than 30 microorganisms. It was found that frozen fish had reduced moisture-holding capacity (MHC). For example: Frozen horse mackerel – 58.91 ± 0.06 %, Frozen catfish – 55.89 ± 0.04 %, Frozen mullet – 53.45 ± 0.08 %, Frozen mackerel – 51.32 ± 0.09 %. The highest MHC among fish products was recorded in: Medium-salted cold-smoked tuna – 64.6 ± 0.05 %, Medium-salted smoked silver carp – 60.32 ± 0.09%, Lightly salted salmon – 59.81 ± 0.07 %–all in accordance with regulatory standards. The histamine content in chilled, frozen fish and fish products did not exceed the regulatory limit of 100 mg/kg, except for hot-smoked horse mackerel, where histamine exceeded the limit by 2.31 %. The sodium chloride content in the tested fish product samples was within acceptable levels: Lightly salted: 6.0–9.0 %, Medium-salted: 9.0–13.0 %, Heavily salted: 13.0–19.0 %. The development and implementation of these unique, express, and optimized methods into the practice of veterinary professionals is highly relevant for advancing the methodology of assessing the safety and quality of fish and fish products.