Trout Fillets Research Articles

Effect of lemon juice on the chemical and microbiological quality of rainbow trout (Oncorhynchus mykiss) under refrigerated storage

In recent years, there has been an increasing interest in using food additives from natural sources to improve taste, texture and extend the shelf-life of foodstuffs. The aim of this study was to examine the quality changes in trout treated with lemon juice for 21 days. Fish were divided into T0, T1, T2 and T3 and treated with 0, 1%, 2% and 3% lemon juice respectively. The lowest pH was found in T3 followed by T2, T1 and T0. A significant difference in total volatile base nitrogen (TVBN), peroxide value (PV) and free fatty acid (FFA) was observed between the control and treatments, with the lowest increase in T3 followed by T2. Total plate count (TPC) crossed the limit in T2 and T3 on the 21st day, whereas in control and T1, the permissible limit crossed on the 12th and 18th days respectively. The sensory panel rejected the control on the 12th day and T1 and T3 on the 18th day; however, T2 remained acceptable till the 21st day, thus showing the promising effect of lemon juice on the quality of trout fillet and thereby increasing the shelf-life of the product by nine days.

The effect of propolis application on quality properties of vacuum-packed hot smoked rainbow trout (Oncorhynchus Mykiss, Walbaum 1792) fillets during cold storage

This research aimed to apply propolis extract (PE) to extend the shelf life and improve the quality of hot smoked rainbow trout while avoiding apparent changes in organoleptic properties. To this end, the effect of PE at different levels (0,25%, 0,50%, 1%, and 3%) on the physico-chemical, chemical, microbiological, and sensory parameters of vacuum-packed hot smoked rainbow trout (Oncorhynchus mykiss, Walbaum 1792) fillets was investigated throughout cold storage (4 ± 1 °C). The observed shelf life of smoked trout was similar in the control and 0.25% PE groups (56 days). After two weeks (on day 70), the 0.50% and 1% PE groups were spoiled. Finally, on storage day 84, 3% of the PE group was spoiled. The dose of 0.25% PE used in this study was insufficient to show the desired effects on the final product. The application of 3% PE significantly affected the microbiological and chemical properties. However, it had a negative effect on the odor and taste of the products. The 1% PE group demonstrated the most potent sensory properties in color, odor, and overall acceptability. This study shows that 1% PE is useful in hot smoked rainbow trout fillets as a natural antimicrobial and antioxidant.

Exploring the antioxidant and antibacterial capacities of Padina australis extracts, and their utilization in starch-based coatings for preserving rainbow trout (Oncorhynchus mykiss) fillets

This study aimed to investigate different extraction methods for obtaining phenolic compounds from Padina australis and evaluate their total phenolic content, antioxidative, and antibacterial activities. The extracts were further incorporated into a starch solution to create active coatings for rainbow trout (Oncorhynchus mykiss) fillets during cold storage. Results showed that microwave-ultrasound-assisted extraction yielded the highest phenolic content and extraction yield. Microwave, microwave-assisted, and microwave-ultrasound extraction methods exhibited the highest ABTS, DPPH scavenging activity, and FRAP, respectively. Additionally, microwave-ultrasound, microwave, microwave-ultrasound, and microwave-assisted extraction methods demonstrated the highest inhibition zone against various bacteria. Fish fillets treated with coatings containing extracts from microwave-ultrasound-assisted extraction exhibited the lowest peroxide values, free fatty acid content, total volatile basic nitrogen, and bacterial counts. These findings suggest that phenolic compounds from P. australis could be utilized in the development of active packaging with antimicrobial and antioxidant properties.

The effect of chitosan coatings enriched with garlic extract and coriander essential oil on the shelf life of rainbow trout (Oncorhynchus mykiss) fillet stored at 4 °C

SummaryThis study was conducted to evaluate the effect of chitosan coating enriched with garlic extract (GE) and coriander essential oil (CEO) on the shelf life of rainbow trout fillet. Treatments were prepared with chitosan coating (2%) containing GE and CEO (0.1% and 0.5%) both separately and in combination. The results showed that GE and CEO had significant effects on peroxide value (PV), thiobarbituric acid (TBA), total volatile basic nitrogen (TVB‐N), total viable (TVC) and psychrotrophic (PTC) counts in fillet samples during storage. It was observed that an increase in the concentration of GE and CEO in the coatings would lead to a significant decrease in the amounts of PV, TVB‐N and TVC. The concentration of 0.5% CEO was more effective than GE on PV, TVB‐N and microbial counts. The treatment coated with chitosan containing 0.5%GE + 0.5%CEO had the lowest PV (5.56 mEq/kg), TBA (2 mg MDA/kg), TVB‐N (32.57 mg N2/100 g), TVC (7.12 log CFU/g) and PTC (5.22 log CFU/g) on the 12th day of storage. The results indicated that the chitosan coating enriched with 0.5%GE + 0.5%CEO can extend the shelf life of refrigerated trout fillets for 6–9 days compared to the control and chitosan alone samples.

Investigation of the Use of Waste Commercial Plant Pulps as Edible Fish Coating Material

In this study, the effects of pulps obtained after cold press oil production was tested as edible fish coating material. It was determined by PV and TBARS values that waste pulp prevented undesirable quality changes due to lipid oxidation. While coating process with black cumin, pumpkin seed and poppy pulp stopped YM development, the lowest TVC values were observed in poppy and black seed groups. Sensory results showed that the use of plant pulps extended the shelf life of rainbow trout fillets, with poppy and black cumin pulps being the most effective groups in terms of odor, taste, texture and general acceptability.

The fabrication of films based on polymer and containing nanoclay, sodium diacetate, and tert‐butyl hydroquinone for packaging rainbow trout

This study investigates the fabrication of films based on a polymer containing nanoclay, sodium diacetate (SDA), and tert-butyl hydroquinone (TBHQ) for packaging rainbow trout fillets. The films were prepared by the addition of 2% SDA (SDA film), 2% TBHQ (TBHQ film), and a combination of both (1% SDA+1% TBHQ) into polyethylene polymer (93.00%) and montmorillonite nanoclay (5.00%). A film lack of nanoclay, SDA, and TBHQ was prepared and considered a control film. A film was also prepared by the addition of 95g polyethylene+5g nanoclay (Nanoclay). Morphological properties of the films were investigated by a scanning electron microscope (SEM). In vitro antioxidant properties and antibacterial activities of the films and their effects as the coating on fish samples were evaluated against Listeria monocytogenes, Salmonella typhimurium, and Escherichia coli. The effects of films on oxidative stability, antibacterial activity, pH, total volatile basic nitrogen (TVBN), and total viable count (TVC) of fish samples were assessed. The SEM results showed the homogenous dispersion of SDA and TBHQ into films. The SDA, TBHQ, and ST films showed antibacterial activity against L. monocytogenes, S. typhimurium, and E. coli compared with the control film as the coating and under in vitro conditions (p<0.05). The TBHQ and ST films exhibited higher antioxidant activity and prevented the oxidation as the coating. The films prepared from the SDA, TBHQ, and ST prevented an increase in TVC and TVBN (p<0.05). The ST films can prevent spoilage in fish samples and can be utilized in the food industry. PRACTICAL APPLICATION: We successfully prepared films with the help of nanoclay, sodium diacetate (SDA), and tert-butyl hydroquinone (TBHQ) on polyethylene for packaging fish fillets. Films containing SDA, TBHQ, and nanoclay showed antibacterial activity and prevented spoilage. The films can be used for packaging fish fillets.

Consumer preference for altered color of rainbow trout (Oncorhynchus mykiss) fillet induced by Spirulina (Arthrospira platensis)

Growing global demand for fish in combination with stagnating capture fishery production challenges aquaculture. Aquaculture is dependent on fishmeal which is criticized for its overall environmental impact. Sustainable growth of aquaculture requires the integration of alternative protein sources. Spirulina has been found to be a viable fishmeal substitute in various fish species and it is known to elevate yellow pigmentation which results in an unusual yellow color for trout fillets. For this reason, the influence of fillet color and other attributes like, country of origin, price and feed claims have on consumer preferences for trout fillet was tested. A discrete choice experiment was conducted to assess German consumer preferences and willingness to pay for yellow fillet color compared to conventional white fillet. Results indicate that spirulina-fed yellow fillet color will not deter consumers away from the unfamiliar colored product, when informed about the potential benefits of spirulina as a fish feed. In fact, informed consumers prefer the spirulina colored product compared to the more usual white fillet. Furthermore, respondents revealed the strongest preferences for fillets of domestic origin (Germany) ahead of Denmark and Turkey. In contrast, feed claims showed no significant effect, except for the claim “fed with sustainable resources”, which had marginal impact. Marketing activities to successfully integrate sustainable feeds like spirulina for rainbow trout into the German fish market should foremost focus on consumers' interest in domestic or nearby production. It seems valuable to raise consumers' awareness of sustainable value chains and production methods in aquaculture through an effective transfer of information.

Effect of coating with chitosan enriched with different borates on the shelf life of fish fillet.

In this study, the effects of biofilm coatings obtained by immobilization of different borates - namely borax (BX), colemanite (COL), and ulexite (UX) - with chitosan (Ch) on the shelf life of rainbow trout fillets were investigated. The immobilization and characterization of borates in Ch were confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy, and zeta potential analysis. In determining the shelf life of fillets that were covered by immersion and stored for 15 days, microbiological (total aerobic mesophilic, psychrotrophic, lactic acid, Pseudomonas, and Enterobacteriaceae bacteria counts) and chemical analyses (total volatile basic nitrogen, thiobarbituric acid reactive substance, and pH levels) were performed at 3day periodic intervals. In addition, the biodegradation of borates was determined using inductively coupled plasma mass spectrometry in biofilm-coated fillets on the 1st, 8th, and 15th storage days. The microbial results of the coatings enriched with borates (BX, COL, and UX) at different levels (0, 0.03, and 0.06 mg L-1 ) (due to the immobilization with Ch) show the shelf life was extended by 3-6 days in all of the treatment groups compared with the control. It was concluded that BX, COL, and UX coatings enriched by immobilization with Ch increase shelf life and improve fillet quality. In addition, the enrichment of BX, COL, and UX with Ch showed explicit natural protective effects. This study demonstrates that Ch-enriched coatings of BX, COL, and UX can be used as natural bioactive nanocarriers to provide bioactive food ingredients in the seafood processing industry. © 2023 Society of Chemical Industry.

Effectiveness of High-Pressure Processing Treatment for Inactivation of Listeria monocytogenes in Cold-Smoked and Warm-Smoked Rainbow Trout

High-pressure processing (HPP) is a promising method for preserving food, for example by inactivating pathogens and spoilage microbes. However, there is still a lack of knowledge about the optimal processing parameters for different food products. The aim of this study was to assess the effectiveness of different pressures to inactivate Listeria monocytogenes in cold-smoked and warm-smoked rainbow trout (Oncorhynchus mykiss) ready-to-eat (RTE) fish products. L. monocytogenes ATCC 7644 was inoculated into sliced cold-smoked rainbow trout fillets and whole warm-smoked rainbow trout fillets. The fish samples were pressure-treated at three different pressures, either at 200, 400, or 600 MPa, at 4 ± 1 °C for 3 min in each pressure. Bacterial enumeration of the samples and control samples were analysed 1, 14, and 28 days after the HPP treatment by using serial dilution and the spread plate technique. Based on the study results, the most effective pressure was 600 MPa and the number of L. monocytogenes colonies, both in cold-smoked and in warm-smoked fish samples, was within the official limit of the Regulation (EC) No. 2073/2005 (100 cfu/g) even after 28 days of storage.

Dietary uptake of geosmin in rainbow trout (Oncorhynchus mykiss)

Geosmin is a primary source of muddy/earthy ‘off-flavors’ in farmed fish, which may render their organoleptic quality unacceptable to consumers. Model systems of geosmin uptake typically comprise exposure to waterborne geosmin that is absorbed via the gills. The present research demonstrates dietary exposure as an alternative route of geosmin uptake in Rainbow Trout (Oncorhynchus mykiss) fillets. Trout (average initial weight of 355 g) were stocked in quadruplicate compartmentalized raceways (N = 4 compartments per treatment, n = 50 fish per compartment) supplied with first-use, flow-through water (4.5 complete turnovers per hour). Fish were fed diets containing 0 (control dose), 0.005 (low dose), 0.05 (medium dose), or 0.5 (high dose) mg geosmin/kg feed at 1% body weight/day for four weeks. Fillets (12 fillets/diet/week plus 12 pre-trial fillet samples) and weekly feed and water samples were analyzed via GC–MS to determine geosmin concentrations. Feeding behavior was documented daily according to a four-point scale. ANOVA with post-hoc Tukey tests and polynomial contrast, regression, correlation, and chi-squared statistical analyses were applied to data (α = 0.05 significance level). Palatability of feed did not hinder consumption of the geosmin-spiked feeds: although fish responded positively to all feeds, the most aggressive feeding behavior was observed among those fed medium and high dose feed. Geosmin was effectively imparted into fillets after one week, and no significant temporal effect was found after four weeks. Mean geosmin concentrations significantly increased in fillets from low (mean of 26 ng/kg geosmin) to medium (202 ng/kg) to high (441 ng/kg) dose feed groups during the trial. Polynomial contrasts and regression modeling validated this significant positive effect of dose on geosmin uptake, with an estimated 166 ng/kg rise in fillet-geosmin for every log10 increase in feed concentration. Waterborne geosmin levels immediately post-feeding were conditionally independent of concentrations in feed and fillets, therefore dietary uptake was affirmed as the predominant mechanism of absorption in the present experimental system. Based on these findings, geosmin-spiked feeds may be used to induce predictable, repeatable levels of this off-flavor compound in fillets and serve as a model system for further investigation of sensory quality and off-flavor mitigation strategies for farm-raised fish.

Effects of hypoxia on meat qualities and muscle metabolism in rainbow trout (Oncorhynchus mykiss) during short-time transportation and its relief by reoxygenation

For rainbow trout, hypoxia usually occurs during transportation and leads to deterioration of meat qualities. Hence, the study aimed to investigate the impacts of hypoxia during short-time transportation on the muscle quality of rainbow trout and its relief attempt by reoxygenation. In comparison with the sample without hypoxia (CG), the fillets from sever hypoxic trout (SHG) exhibited lower shearing force (SF), a⁎, saturated fatty acid content and delicious amino acids, and higher expressible moisture, Metmyoglobin (MetMb) and essential amino acids content. After subjected to reoxygenation for 24 h, the muscle qualities of trout recovered to the level of CG, except for expressible moisture and tissue structure. Metabolomic analyses indicated that hypoxia led to the up-regulation of succinate, xanthine, adenine and down-regulation of 15(S)-HETE ((15S,5Z,8Z,11Z,13E)-15-Hydroxyeicosatetraenoic acid). And the reoxygenation promoted glycine and serine biosynthesis, thiamine and cysteine metabolism and inhibited succinate accumulation, thus relieved the hypoxia. This work suggested that reoxygenation for 24 h was an effective action to relief the quality deterioration of rainbow trout fillets induced by hypoxia.

Limon ve Portakal Kabuğu Ekstraktları Içeren Yenilebilir Film Kaplamaların Kalamar (Loligo vulgaris) Halkaları ve Gökkuşağı Alabalığı (Oncorhynchus mykiss) filetolarında Mikrobiyolojik Kalitesi ve Raf Ömrü Üzerine Etkisi

The aim of this study is to produce edible films with antimicrobial properties by using the discarded fruit peels (orange and lemon) as extracts and to determine the effect on shelf life of rainbow trout fillets and squid rings. For this purpose, antimicrobial edible films were performed the orange and lemon peels extracts by using xanthan, locust bean and carrageenan gums. Rainbow trout fillets (Oncorhynchus mykiss 1792) and squid rings (Loligo vulgaris 1798) were covered with this antimicrobial edible films from discarded fruit peels to extend the shelf-life of these products. As a result, total mesophilic bacteria count (TMC) of squid rings (CS) exceeded the microbiological limit of the consumption on day 6, whereas TMC of squid rings covered with limon peel+locust bean (LLS) and limon peel+carrageenan (LKS) did not exceed this limit on day 8. This study gave rise to not only can be produced of functional products from the fishery products but also the fruit peels residues can also be evaluated for this purpose. The results of this study can be evaluated by seafood and fruit juice processing plants as well as food producers.

Investigation of Antibiotic Residue, Nitrofuran Compounds, Microbial Properties and Heavy Metal Amount in Rainbow Trout (Oncorhynchus mykiss)

ABSTRACT The aim of this study was to determine the pathogenic microorganisms, antibiotic residues, and metal concentrations in rainbow trout (Oncorhynchus mykiss) fillets grown in 3 different regions in Trabzon and to determine their compliance with the limit values determined by national (Turkish Food Codex) and international legislation (Codex Alimentarius commission, European Comission). Of the 46 antibiotic residues and 4 nitrofuran residues searched, none of the fillets were detectable and all were below the maximum residue limit. The highest number of aerobic colony count was found at 3.2 × 104 (A2 location). Enterobacteriaceae<10 cfu/g, Escherichia coli<3 MPN/g and<10 cfu/g, Staphylococcus aureus<10 cfu/g, and Coliform bacteria<3 MPN/g and<10 cfu/g were detected. Listeria monocytogenes, Salmonella spp. Vibrio cholera, and Vibrio parahaemolyticus were not found in any of the locations. Metal concentrations, Pb, Cd, and Hg observed were below the limits set by the legislation. The results show that rainbow trout fillets cultivated in offshore fish farms in 3 different regions are below the maximum limit values specified in national and international regulations in terms of antibiotic residue amount, heavy metal content, and microbiological properties.

Investigation of ultrastructure and texture changes of fillets of rainbow trout grown under different aquaculture systems.

In this study, the physical structure of fillets of rainbow trout (Oncorhynchus mykiss) grown under different aquaculture conditions was compared. For this purpose, scanning electron microscopy (SEM) analysis, texture profile (hardness, springiness, cohesiveness, gumminess, chewiness), and color measurements (L, a, b, chroma, hue and whiteness) of the fillets of trout taken from two different aquaculture environments were examined. When the texture profile of fillets taken from both environments was compared, it was determined that the hardness (40.30-69.80 N), gumminess (26.85-41.89 N) and chewiness (25.37-36.82 N) values of the fish samples taken from the extensive culture were higher than the samples taken from the recirculated system. The difference between other values was not found to be significant. In parallel with the hardness results, when the SEM images were examined, it was determined that the fillets of the fish taken from the extensive system had a thicker fibril ultrastructure than those from the RAS. The variable environmental parameters and aquaculture duration were observed to have an effect on muscle development, and that especially the long breeding period in the extensive system has a positive effect on the meat structure of the fish. Cultivation in different environments was not determined to have a significant effect on the color values of either the skin or fillet samples. As trout is the leading fish in freshwater production, it is very important for aquaculture to determine the physical changes in the flesh structure of trout according to the growing conditions.

Combined effect of atmospheric gas plasma and UVA light: A sustainable and green alternative for chemical decontamination and microbial inactivation of fish processing water

The simultaneous use of UVA light irradiation coupled with low energy cold plasma generated by a dielectric barrier discharge prototype, results in significant enhancement of efficiency of the integrated process with respect to the sole plasma treatment. This effect has been demonstrated both on microbial inactivation of a food-borne pathogen, i.e. Listeria monocytogenes, and on the degradation of a compound of biological origin such as phenylalanine. In the latter case, the analysis of its reaction intermediates and the spectroscopic identification and quantification of peroxynitrites, allowed to propose mechanistic hypotheses on the nature of the observed synergistic effects. Moreover, it has been demonstrated that the process does not affect the quality of trout fillets, indicating its suitability as a chlorine-free, green, and sustainable tool for the decontamination of fish processing water.

Cover Caption

AbstractJanuary Online Cover: Example photos of rainbow trout fillets with backlight vs. frontlight for segmentation and color analysis; photo of a fish with locations of sensory panelists' point selection, selected SalmoFan numbers, and δE error; fish photos where yellow borders depict the areas where a* &gt; 25; and a chart showing SalmoFan numbers predicted by the 3D L*a*b* method for the 122 fillets tested; from “Color of rainbow trout (Oncorhynchus mykiss) fillets by image and sensory analysis, and correlation with SalmoFan numbers” by Bahar Gümüş, Erkan Gümüş, Murat O. Balaban 57.

The Effect of Sausage Production as Alternative Processing Product and Use of Natural Antioxidants on the Evaluation of Trout Fillet Waste

Seafood is one of the leading meat products with high biological and nutritive value. Dried fermented products are called sausage, as a result of the maturation process under certain conditions by filling the material prepared in the form of dough into natural/artificial casings. Oxidation is one of the most important parameters affecting shelf life in seafood containing high levels of unsaturated fatty acids. With the knowledge of the harms of synthetic antioxidants, the plant and its parts from which natural antioxidants are obtained have come to the fore. In this study, sausage dough prepared from trout fillet waste was filled in artificial casings and fermented under specified conditions, to produce sausage. Prepared sausages were divided into 3 groups as the control group without additives, with natural additives (pomegranate peel extract) and artificial additives (ascorbic acid). The proximate, chemical and physical changes of sausages, which were heat treated, stored at +4 ºC were examined. According to the results, ATVB-N and TBA of all sausage groups, exceed the limit values on the 5th day of storage. It was determined that the shelf life of the sausage obtained in the study was limited to 5 days; however, the values of the sausage group with pomegranate peel extract were found to be lower than the other groups. As a result, although the shelf life of sausage groups was limited to 5 days, it was observed that pomegranate peel extract could be used instead of synthetic preservatives with its antioxidant and antimicrobial properties.

Comparative study on the fillet nutritional quality of diploid and triploid rainbow trout (Oncorhynchus mykiss)

This study was conducted to investigate the fillet nutritional quality difference of diploid and triploid rainbow trout with the same genetic background, farming condition and body weight. The results showed that, 1) diploid rainbow trout had significantly higher content of protein, valine, cysteine, histidine and proline, and higher essential amino acid index, nutrition index and biological value than triploid rainbow trout (P < 0.05). However, essential amino acids and total amino acids contents as well as amino acid score and chemistry score were similar between the two fish (P > 0.05), which indicated that both diploid and triploid rainbow trout fillets were balanced and suitable for human consumption. 2) Triploid rainbow trout had significantly higher content of lipid, C18:1n-9, C18:2n-6, C20:5n-3, C22:6n-3, unsaturated fatty acids (UFA), polyunsaturated fatty acids (PUFA), long chain polyunsaturated fatty acids, n-3 series fatty acids, n-6 series fatty acids and total fatty acids (TFA) than diploid rainbow trout (P < 0.05). However, no differences were found in saturated fatty acids (SFA), C18:3n-3 and C20:4n-6 contents between the two fish (P > 0.05). Based on PUFA/SFA, UFA/SFA, PUFA/TFA, atherogenic index, and thrombogenic index, both diploid and triploid rainbow trout consumption were beneficial for human health, triploid fish had an even greater advantage. 3) Triploid rainbow trout had higher content of sodium, calcium, iron, manganese and zinc but lower content of magnesium, copper and selenium than diploid rainbow trout (P < 0.05). Multivariate statistical analysis of 79 quality indicators also showed that the fillet nutritional composition of triploid rainbow trout was different with its diploid counterparts. The reason may be related to the difference of lipid metabolism in rainbow trout with different ploidy.

Thermal degradation characteristics of amino acids in rainbow trout fillets during traditional high temperature short time processing and microwave processing

Thermal degradation characteristics of amino acids in rainbow trout fillets during traditional high temperature short time processing and microwave processing

Nitrogen factors for rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis) fillets

Measures for consumer protection against food adulteration and misleading labelling are integrated into EU legislation, including methods for detecting misleading practices. Verification of the meat content is available for marine products, but not for salmonid fish due to the lack of standard nitrogen factors. This study aimed to establish nitrogen factors for rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis). The study analysed 340 fish from Czech fisheries obtained in the summer of 2018–2020. According to the established ISO methods, fillet samples with and without skin were analysed for their nitrogen content (protein), dry matter, ash, and fat. The recommended nitrogen factor for rainbow trout fillets with and without the skin is 3.07 ± 0.12 and 3.06 ± 0.14, respectively, and the nitrogen factor for fat-free rainbow trout fillets with and without the skin is 3.33 ± 0.15 and 3.29 ± 0.15, respectively. The recommended nitrogen factor for brook trout fillets with and without the skin is 3.16 ± 0.10 and 3.12 ± 0.09, respectively, and the nitrogen factor for fat-free brook trout fillets with and without the skin is 3.42 ± 0.13 and 3.36 ± 0.12, respectively. The established nitrogen factors will enable the analysis of the meat content to ensure that consumers purchase correctly described and labelled fish products.