Fish Fillets Research Articles

Biomass of the oleaginous yeast Rhodotorula toruloides as feed ingredient in the diet of Arctic char (Salvelinus alpinus): impact on quality; safety and sensory outcome

ABSTRACT The aim of this study was to test the impact of replacing vegetable oils commonly used in the feed of Arctic char (Salvelinus alpinus) with biomass of the oleaginous yeast Rhodotorula toruloides. For that, a control feed containing vegetable oils and an experimental feed including yeast biomass at 15% level, were fed to Arctic char. Sensory properties of the fish were tested. The content of undesirable compounds in the new feed ingredient were evaluated. Selected heavy metals and organic pollutants were measured in the yeast biomass and the levels found were below the limits of the regulations defined by the European Union. Moisture and ash contents were similar between the two feeds. Hepatic activity of 7-ethoxyresorufin-O-deethylase was evaluated between the two fish groups and no significant differences were observed. The sensory analysis conducted on heat treated fish fillets with untrained volunteers showed no perceptible sensory difference.

Effect of tomato seed mucilage coating enriched with shallot essential oil on frozen rainbow trout (Oncorhynchus mykiss) fillet quality

The present study aimed to investigate the interaction effects of tomato seed mucilage (TSM) coating and shallot essential oil (SEO) (0%, 1%, and 2%) on the physicochemical, and microbial properties of Rainbow Trout (Oncorhynchus mykiss) during frozen storage (0, 1, 2, 3, and 4 months). The results indicated that the TSM coating treatments, especially, with the increase in SEO concentration effectively reduced the total viable count (TVC) and psychrotrophic bacteria count (PTC). Moreover, it decreasing the rate of changes in thiobarbituric acid (TBA), total volatile basic nitrogen (TVB-N), and peroxide value (PV). The TVB-N levels were within acceptable limits, except for the Ctrl treatment in the fourth month, where the TVB-N in fish fillet was exceeded 25 mg/100g. The incorporation of SEO to the TSM coating led to a decrease in pH variations, protein solubility, and moisture content of the Rainbow Trout fillets during frozen storage. At the end of the storage period, Hardness in the Ctrl treatment at the end of storage period were respectively 14.95%, 21.91%, and 24.52% lower than those in the TSM-0% SEO, TSM-1% SEO, and TSM-2% SEO treatments. Furthermore, at the end of the frozen storage period, the color changes in all treated fillets were significantly lower compared to the Ctrl treatment (p < 0.05). Overall, utilizing a 2% SEO-containing TSM treatment demonstrated the best performance in delaying undesirable qualitative changes. Hence, there is promising potential in using TSM as agricultural waste in combination with active compounds like SEO to produce an active coating. These coatings, according to their characteristics, can serve as a cost-effective, efficient, and safe option for preserving perishable marine products.

Plasma-activated water in combination with coconut exocarp flavonoids emerge as promising preservation technique for golden pompano: Impact of the treatment sequence

In the current study, the preservation effect of plasma-activated water (PAW), coconut exocarp flavonoids (CF) and their combination on golden pompano fillets during refrigerated storage was investigated with emphasize on the treating sequence. PAW effectively inactivated spoilage bacteria and inhibited total volatile basic nitrogen (TVB-N) increase, while boosted the TBARS and carbonyl values. PAW+CF exerted synergistic effect on extending the period before total bacterial count and TVB-N content reaching acceptance limit than PAW or CF alone (P < 0.05). In addition, their combined treatment effectively reduced fillets discoloration and texture deterioration. Simultaneously, lipid and protein oxidation were significantly inhibited, which was comparable to CF. It was indicated that the treatment sequence of PAW and CF profoundly impact the preservation effect. Specifically, prior CF marinating followed by PAW was more effective than the opposite sequence. Thus, combination of CF followed by PAW served as promising technique for fish fillets preservation.

Investigation of physio-mechanical, antioxidant and antimicrobial properties of starch–zinc oxide nanoparticles active films reinforced with Ferula gummosa Boiss essential oil

The production of surface compounds coated with active substances has gained significant attention in recent years. This study investigated the physical, mechanical, antioxidant, and antimicrobial properties of a composite made of starch and zinc oxide nanoparticles (ZnO NPs) containing various concentrations of Ferula gummosa essential oil (0.5%, 1%, and 1.5%). The addition of ZnO NPs improved the thickness, mechanical and microbial properties, and reduced the water vapor permeability of the starch active film. The addition of F. gummosa essential oil to the starch nanocomposite decreased the water vapor permeability from 6.25 to 5.63 g mm−2 d−1 kPa−1, but this decrease was significant only at the concentration of 1.5% of essential oils (p < 0.05). Adding 1.5% of F. gummosa essential oil to starch nanocomposite led to a decrease in Tensile Strength value, while an increase in Elongation at Break values was observed. The results of the antimicrobial activity of the nanocomposite revealed that the pure starch film did not show any lack of growth zone. The addition of ZnO NPs to the starch matrix resulted in antimicrobial activity on both studied bacteria (Staphylococcus aureus and Escherichia coli). The highest antimicrobial activity was observed in the starch/ZnO NPs film containing 1.5% essential oil with an inhibition zone of 340 mm2 on S. aureus. Antioxidant activity increased significantly with increasing concentration of F. gummosa essential oil (P < 0.05). The film containing 1.5% essential oil had the highest (50.5%) antioxidant activity. Coating also improved the chemical characteristics of fish fillet. In conclusion, the starch nanocomposite containing ZnO NPs and F. gummosa essential oil has the potential to be used in the aquatic packaging industry.

Copper in Commercial Marine Fish: From Biomonitoring to the ESG (Environment, Social, and Governance) Method

The presence of potentially harmful metals in commercially available saltwater fish has been extensively documented in scientific literature. This has demonstrated the significance of monitoring the crucial copper (Cu) levels in fish fillets from a perspective focused on human health risks (HHR). This study aimed to evaluate the human health risk (HHR) associated with the presence of Cu in 40 different species of commercial marine fish purchased from Malaysia. The fish samples were gathered from various sources from April to May 2023. The 40 species of commercial marine fish had concentrations of Cu (0.72–82.3 mg/kg dry weight) that fell below acceptable levels defined by seafood safety recommendations. Therefore, these fish are considered good sources of the essential element. The target hazard quotient values for Cu were below 1, suggesting that the hazards of Cu from fish eating are non-carcinogenic. Furthermore, it was discovered that the computed values for the predicted weekly consumption were lower than the defined provisional tolerated weekly intake of Cu. Consuming fish purchased from Malaysia is unlikely to harm consumers’ necessary copper intake. However, it is crucial to consistently monitor the safety of consumers who heavily depend on commercially caught marine fish from Malaysia. This monitoring is an essential aspect of implementing environmental, social, and governance (ESG) practices, which industries are concerned about and report on annually.

New insights into the effect of xylooligosaccharide derived from agricultural waste, single or combined dietary supplementation with mixed probiotics on growth, flesh quality, health condition and disease resistance in Nile tilapia (Oreochromis niloticus)

This study aimed to study the effects of single or combined dietary supplementation of xylooligosacharides (XOs), prebiotics derived from agricultural waste and mixed probiotics (Bacillus subtilis TISTR 008 and Lactobacillus plantarum TISTR 1854) on growth performance, flesh quality, health condition and disease resistance in Nile tilapia (Oreochromis niloticus). Fish received four types of diets: a basal diet (control); XOs (prebiotics); a mixture of Bacillus subtilis TISTR 008 and Lactobacillus plantarum TISTR 1854 (probiotics); and a combination of XOs and a probiotic mixture (synbiotics) for 56 days. The results show that dietary prebiotics, probiotics, and synbiotics improved growth performance including final body weight, weight gain, average daily gain, and protein efficiency ratio compared to the control diet. Interestingly, the feed conversion ratio was improved by dietary prebiotics, probiotics, and synbiotics supplementation. Concurrently, innate immunity parameters such as total antioxidant, lysozyme, catalase, and glutathione S transferase were mostly higher in fish fed the prebiotics, probiotics, and synbiotics diets. Moreover, we observed significant increases in digestive enzyme activities, including protease, amylase, and lipase, in fish fed probiotic diets. After the feeding trial, fish were intraperitoneally injected with Streptococcus agalactiae, and the cumulative 14-day mortality rate was calculated. High survival rates were observed in all groups that received supplementation with prebiotics, probiotics, or synbiotics in their feed. This improvement is correlated with an increase in the transcriptional levels of immune- and growth-related factors. Interestingly, this study highlights the use of prebiotics and synbiotics containing XOs to boost the PUFA n-3 and n-6 content in the fish fillets. Our findings indicate that adding XOs as prebiotics to the diet significantly enhances the overall performance of fish when compared to the effects of probiotics and synbiotics. In summary, XOs may have the potential as organic compounds derived from agricultural waste for specific probiotic and synbiotic products in the aquaculture industry when combined in the right proportions.

Enhancing the Quality of Refrigerated Smooth-Hound Shark Fillet with a Fish Gelatin Coating Enriched with Garden Cress Extract

ABSTRACT Smooth-hound fillets were coated with skin gelatin extracted from the skin of the same fish. The gelatin coating solution was enriched with garden cress seed extract (GCSE) at 0.67 mg/g of gelatin. Analysis of the phenolic profile revealed that quinic acid (844 µg/g extract) was the major compound, likely to participate along with other phenolics in enhancing the preservative capacity of GCSE-gelatin coating. Interestingly, psychrophilic/mesophilic bacteria, MDA equivalent, TVB-N and FAA contents in the coated samples were significantly reduced compared to the control, proving the potential of the GCSE-enriched gelatin coating on extending fish fillet shelf-life.

Concentration of Tetrabromobisphenol-A in fish: systematic review and meta-analysis and probabilistic health risk assessment.

Tetrabromobisphenol A (TBBP-A) is an emerging pollutant that enters water resources and affects various marine organisms, such as fish. Consequently, numerous studies globally investigated TBBP-A concentrations in fish fillets of the current study were meta-analyze concentration of TBBP-A in fish fillets and estimate the associated health risks for consumers. The search encompassed international databases, including Science Direct, PubMed, Scopus, Embase, and Web of Science from January 1, 2005, to July 20, 2023. The ranking of countries based on the pooled (Mean) concentration of TBBP-A in fish was as follows: China (1.157 µg/kg-ww) > Czech Republic (1.027 µg/kg-ww) > France (0.500 µg/kg-ww) ∼ Switzerland (0.500 µg/kg-ww) > Netherlands (0.405 µg/kg-ww) > Germany (0.33 µg/kg-ww) > Sweden (0.165 µg/kg-ww)>UK (0.078 µg/kg-ww) > Belgium (0.065 µg/kg-ww) > South Korea (0.013 µg/kg-ww) ∼ Japan (0.013 µg/kg-ww) > Ireland (0.005 µg/kg-ww). The risk assessment showed that the carcinogenic and non-carcinogenic risks of TBBP-A in China and France are higher compared to other countries; however, within all countries, these risks were found to be within acceptable limits.

Nanopore sequencing facilitates screening of diversity and provenance of seafood and marine wildlife

The soaring global demand for seafood has placed unprecedented pressure on fisheries, leading to the exploitation of vulnerable marine resources and data-deficient species. Over the past few decades, a surge of molecular methods has enabled identification of traded marine animal products that may be otherwise unrecognizable through morphological analysis. While universal DNA barcoding remains a powerful authentication and traceability tool, its application still requires lengthy procedures, established facilities, and assay development. In this study, we explored some of the uses and advantages of cutting-edge nanopore sequencing, a rapid and portable alternative method. We first tested the method to identify ten opportunistically sampled fishery products obtained in two different contexts: five fish fillets marketed in the UK, four shark specimens traded in Indonesia and one fish collected as part of a scientific survey. We present a full analytical workflow to produce accurate species identification based on direct, PCR-free long-read sequencing of the DNA extracted from each specimen. We then used the nanopore sequencing output to mine whole mitogenomes from samples of varying DNA quality. Finally, we used the extensive additional genomic information produced by the sequencing to pinpoint the geographic origin of two of the identified specimens for which robust baseline data existed. In the face of increasing threats to biodiversity, and the need to control exploitation and supply of fisheries and wildlife globally, this rapid and portable approach is poised to revolutionize the monitoring of seafood supply and the trade in endangered marine wildlife, contributing to the sustainable management of aquatic resources.

Development of a water gradient film through film and ice-glazing approach utilizing konjac glucomannan and high acyl gellan gum for enhanced preservation of frozen snakehead (Channa argus) fillets

Fish fillets are perishable, and several commonly used preservation methods, such as freezing, ice-glazing, and plastic film packaging, aim to maintain their quality during frozen storage. This study presents a novel approach by developing a water gradient edible film using konjac glucomannan (KGM) and high acyl gellan gum (HAGG), and evaluates its effectiveness in preserving frozen snakehead (Channa argus) fillets. First, KGM/HAGG films with different weight ratios of KGM and HAGG were prepared and their properties were characterized. H-bond interactions occurred between KGM and HAGG, resulting in their compatibility and the formation of a homogeneous structure. The properties of the KGM/HAGG films, including tensile strength, elongation at break, water vapour permeability, oxygen permeability, and water swelling ratio, could be modified by changing the weight ratios of KGM and HAGG. The water gradient film was then prepared by adding water to one surface of the film, resulting in controlled swelling. This water gradient film exhibited a water gradient property before freezing and a combined film and ice-glazing property after freezing. It acted as both a moisture and oxygen barrier, while also acting as a moisture-sacrificing agent during frozen storage. When compared to unpackaged fillets, ice-glazed fillets, and fillets packaged with polyethylene film, the frozen water gradient film proved to be the most effective in preserving snakehead fillets during a 150-day frozen storage period. These findings indicate that the KGM/HAGG water gradient film could be a valuable alternative to conventional preservation methods for maintaining the quality of fish fillets during frozen storage.

Development of halochromic electrospun labels for non-invasive shelf life assessment of rainbow trout (Oncorhynchus mykiss): Incorporation of barberry anthocyanin extract in protein-based smart packaging.

Using barberry (Berberis vulgaris L.) as a natural dye in combination with electrospinning technology represents a promising approach for the development of intelligent packaging systems. In this study, the influence of different concentrations of zein (16, 18, and 20%) and barberry anthocyanin-rich powder (BARP) (16, 18, and 20%) on the surface tension and rheological properties of the solution were evaluated. The most favorable nanofibers (NFs) were obtained from a solution containing 18% (w/w) zein under constant voltage. The surface morphology, size, and color-changing properties of electrospun NFs derived from zein polymers containing different concentrations of BARP (16, 18, and 20%) under various electrical fields (20, 22, and 24 kV) were evaluated. The Fourier-transform infrared spectroscopy analysis confirmed the interaction of BARP within the zein-based NFs. The results indicated that the concentration of BARP had a noticeable impact on the physicochemical properties of the NFs. Furthermore, efficacy of the appropriately fabricated halochromic label was evaluated for monitoring the packed rainbow trout fillet during refrigerated storage. On the 10th day, a noticeable visual color turned from pink to pale yellow was observed in response to pH variations. Additionally, the TVN value confirmed the effectiveness of halochromic electrospun labels for non-invasive assessment of fish fillet quality.

Integrated alternative approaches to select feed-efficient rainbow trout families to enhance the plant protein utilization

Improving feed utilization efficiency is a challenge in aquaculture. Therefore, we developed an indirect benchmark to use in selecting trout for improved efficiency of feed utilization on plant protein (soy)-based diets, with the long-term goal of reducing the cost of commercial trout production. We used a four-part integrative approach to identify feed efficient individuals among 1595 fish coming from 12 genetically selected families by establishing the phenotypic relationship between feed conversion ratio (FCR) and body weight variations using compensatory feeding regimes. Additionally, we examined the nutritional composition of fish filet for each efficiency phenotype during the compensatory regimen. Our findings showed that the fish with the lowest weight loss during a feed deprivation period and the highest weight gain during the refeeding period (FD−/RF +) demonstrated the lowest FCR (FCR = 0.99) and consisted of individuals from several lines. This finding confirms the possibility of improving feed efficiency in mixed lines. Although feeding period has an effect on nutritional composition of fillet, such selection criteria did not show an effect on groups. Overall, successful selection for the improvement of feed efficiency will have a broad application to commercial fish selective breeding programs, leading to increased aquaculture sustainability in the long run.

Combined Effects of Zein Nanofiber Coating Containing Laurel (Laurus nobilis) and Air Fryer Cooking on Quality Properties of Fish Fillets during Cold Storage.

In this study, the effects of zein nanofibers (Zn) containing ground laurel leaves (GLL) and air fry cooking on the quality characteristics of Rainbow trout (Oncorhynchus mykiss) were investigated. The zein nanofibers possessing 335.8 ± 43.6 nm average diameters were fabricated containing GLL. The Fourier transform infrared spectroscopy (FTIR) results of the zein, Zn, GLL, and zein nanofibers containing GLL (LZn) confirmed the electrospinning encapsulation of GLL into Zn and their interactions. The effects of the combination of LZn coating and air fryer cooking of fish fillets on the quality characteristics during storage at 4 °C for 10 days were monitored in terms of oxidative and microbiological stability, color, and sensory parameters. As compared to the control, the combination of LZn coating and air fryer cooking provided a microbial limitation of up to 45.21% during the analysis (p < 0.05). The changes in ΔE values between the control and the LZn-coated samples were obtained as ≤7.56 during 6 days, but then a dramatic color difference was observed. Besides overall sensory acceptability, particularly the odor parameter in the cooked fish samples coated with LZn was significantly preferred (p < 0.05). The combination of LZn coating and air fryer cooking delayed the thiobarbituric acid increase in the fish meat samples (3.51 to 2.57 mg malondialdehyde (MDA)/kg) up to the third day of storage. This study showed that LZn coating is a very functional layer on the fish meat and could be applied for not only fresh fish meat but also other fresh meat products.

Bio-nanocomposite active packaging films based on carboxymethyl cellulose, myrrh gum, TiO2 nanoparticles and dill essential oil for preserving fresh-fish (Cyprinus carpio) meat quality

This study developed a composite film for packaging refrigerated common carp fillets using carboxymethyl cellulose (CMC) (1.5 % w/v)/Myrrh gum (MG) (0.25 % w/v) base with the addition of titanium dioxide nanoparticles (TiO2 NPs) (0.25 %, 0.5 %, and 1 %) and Dill essential oil (DEO) (1.5 %, 2.25 %, and 3 %). The film was produced using a casting method and optimized for mechanical and barrier properties. The incorporation of DEO and TiO2 NPs into CMC/MG composite films significantly reduced moisture content (MC) and water vapor permeability (WVP), improved their tensile strength (TS), and increased their antimicrobial and antioxidant properties. Moreover, MG can improve the physicomechanical properties of the CMC/MG composite films. The film components had good compatibility without significant aggregation or cracks. In conclusion, the optimized CMC/MG (1.5 %/0.25 %) film containing TiO2 NPs (0.5 %), and DEO (2.25 %) has the best overall performance and can be a good source for making edible film. Functionally, this bioactive nanocomposite film significantly increased the shelf life of refrigerated fish fillet samples for 12 days by inhibiting microbial growth and reducing the oxidation rate compared to the control sample. The knowledge obtained from this study can guide the development of bio-nanocomposite and biodegradable food packaging films based on CMC/MG to increase the shelf life of food products and environmental protection.

Evaluating the persistence of malachite green residues in tilapia and pacu fish

Although banned in food-producing animals, residues of malachite green (MG) and its primary metabolite, leucomalachite green (LMG), have been found in fish due to illegal use in aquaculture and the release of industrial wastewater, which represent a serious risk to food and environmental securities. This study aimed to investigate the residue depletion profile of MG and LMG in edible tissues of Nile tilapia (Oreochromis niloticus) and pacu (Piaractus mesopotamicus) cultured simultaneously under the same environmental conditions to support control measures in case of abuse. An analytical method involving QuEChERS sample preparation and liquid chromatography coupled to tandem mass spectrometry was developed, validated, and applied to quantify MG and LMG residues in fish fillets from two depletion experiments after treatment by immersion bath (MG at 0.10 mg L-1 for 60 min). During the experiment, the average water temperature was 30 ºC, while the pH was 6.9. The method is selective, precise (CV = 0.4 - 22%) and accurate (recovery 92 - 114%). The limits of detection and quantification are 0.15 and 0.5 ng g-1, respectively. In both species, the sum of MG and LMG residues were quantified up to the 32nd day post-exposure, and the concentrations were significantly higher in the pacu fillets (up to 3284 ng g-1) than in Nile tilapia (up to 432 ng g-1). The sums of MG and LMG residues were below 2 ng g-1 at 44 days and 342 days for Nile tilapia and pacu, respectively – the Minimum Required Performance Limit (MRPL) for analytical methods intended to monitor forbidden substances in food according to old European Commission guidelines. The persistence of MG residues in pacu may be attributed to its higher lipid content, which favors the accumulation of the non-polar metabolite LMG. These results provide insights into the concern about human, animal, and environmental health risks resulting from unauthorized use or aquatic contamination by industrial wastewater containing MG residues.

The inhibitory action of lactocin 63 on deterioration of seabass (Lateolabrax japonicus) during chilled storage.

The bacteriocins, particularly derived from lactic acid bacteria, currently exhibit potential as a promising food preservative owing to their low toxicity and potent antimicrobial activity. This study aimed to evaluate the efficacy of lactocin 63, produced by Lactobacillus coryniformis, in inhibiting the deterioration of Lateolabrax japonicas during chilled storage, while also investigating its underlying inhibitory mechanism. The measurement of total viable count, biogenic amines, and volatile organic compounds were conducted, along with high-throughput sequencing and sensory evaluation. The findings demonstrated that treatment with lactocin 63 resulted in a notable retardation of bacterial growth in L. japonicas fish fillet during refrigerated storage compared with the water-treated and nisin-treated groups. Moreover, lactocin 63 effectively maintained the microbial flora balance in the fish fillet and inhibited the proliferation and metabolic activity of specific spoilage microorganisms, particularly Shewanella, Pseudomonas, and Acinetobacter. Furthermore, the production of unacceptable volatile organic compounds (e.g. 1-octen-3-ol, hexanal, nonanal), as well as the biogenic amines derived from the bacterial metabolism, could be hindered, thus preventing the degradation in the quality of fish fillets and sustaining relatively high sensory quality. The results of this study provide valuable theoretical support for the development and application of lactocin 63, or other bacteriocins derived from lactic acid bacteria, as potential bio-preservatives in aquatic food. © 2024 Society of Chemical Industry.

Enhancing frozen fish quality through polysaccharide-ice glazing: Insights from physical properties and preservation effects

Polysaccharide ice-glazing is a widely employed method for preserving frozen fish, with the choice of polysaccharide playing a crucial role in preservation effectiveness. This research investigates the impact of various polysaccharides, including neutral polysaccharides like konjac glucomannan (KGM) and pullulan (PUL), as well as ionic polysaccharides such as gellan gum (GG), κ-carrageenan (KC), carboxymethyl cellulose (CMC), and xanthan gum (XG), on the physical properties of ice. Additionally, we assess the influence of polysaccharide ice-glazing on the quality of frozen snakehead (Channa argus) fish fillets. Our study shows that the physical properties of polysaccharide-infused ice are affected by both polysaccharide type and concentration. Increasing the polysaccharide concentration led to a reduction in water activity within the supercooled polysaccharide solution. Additionally, the characteristics of ice formed by the polysaccharide solution, including ice crystal size, compressive strength, sublimation rate, and oxygen permeability, consistently decreased. In our comparative analysis, at equivalent polysaccharide concentrations, the PUL solution exhibited the lowest water activity. Notably, PUL-ice demonstrated superior performance, displaying the smallest ice crystal size, highest compressive strength, lowest ice sublimation rate, and the most effective oxygen permeability barrier. Following this in decreasing order of performance were the GG, KC, CMC, XG, and KGM samples. Moreover, when applied to glazing snakehead fish fillets, pullulan ice-glazing outperformed KGM ice-glazing in preserving fish quality, confirming the direct influence of polysaccharide-induced ice properties on fillet preservation outcomes. This study provides essential insights to guide informed decisions in the field of polysaccharide ice-glazing applications, aimed at enhancing the quality of frozen fish.

Studying the impact of phycoerythrin on antioxidant and antimicrobial activity of the fresh rainbow trout fillets

Marine cyanobacteria present a significant potential source of new bioactive compounds with vast structural diversity and relevant antimicrobial and antioxidant activities. Phycobiliproteins (PBPs) like phycocyanin (PC), phycoerythrin (PE), and water-soluble cyanobacterial photosynthetic pigments, have exhibited strong pharmacological activities and been used as natural food additives. In this study, phycoerythrin (PE) isolated from a marine strain of cyanobacterium Nostoc sp. Ft salt, was applied for the first time as a natural antimicrobial as well as an antioxidant to increase the shelf life of fresh rainbow trout i.e., (Oncorhynchus mykiss) fillets. Fresh trout fillets were marinated in analytical grade PE (3.9 μg/mL) prepared in citric acid (4 mg/mL), and stored at 4 °C and 8 °C for 21 days. Microbiological analysis, antioxidant activity and organoleptic evaluation of both control and treated fish fillets were then statistically compared. The results demonstrated noticeable (P < 0.05) differences in the microbial counts, antioxidant activity, and organoleptic characteristic values between PE-treated and non-treated groups. In addition, we observed that treating fresh fish fillets with a PE solution leads to a significant increase in shelf life by at least 14 days. Consequently, PE could be an alternative to synthetic chemical additives since it does not contain the potentially dangerous residues of the synthetic chemical additives and is thus healthier to the consumers.

Occurrence and Consumer Health Risk Assessment of Heavy Metals in Frozen Demersal Fish and Cephalopod Products from Benoa Port, Bali Province

Introduction: Heavy metal pollution has become an important environmental issue today. This study was aimed to identify the heavy metals of the two fishing products namely demersal fish and cephalopods landed at Benoa Port, Bali Province and their health risk effects on consumers. Methods: Demersal fish and cephalopod products were obtained from local fishermen at Benoa port. Atomic Absorption Spectrophotometry (AAS) was used to specify the (Pb, Cd, and Hg) in 34 fish fillet products weighing an average of 500 grams each. Statistical software was used to conduct an analysis of the collected data, while THQ, TTHQ, and TCR were calculated and compared with USEPA regulations. Results and Discussion: The results of this research showed that the content of heavy metals in demersal fish and cephalopod products was lower than the levels suggested by official agencies in a number of countries. In populations of various ages, the target Hazard Quotient (THQ) for the heavy metal was less than 1. At this point, the Total THQ result did not imply any risk to human health from ingestion of these two fishery products. When these two products were ingested, the target cancer risk (TCR) did not represent a cancer risk. Conclusion: The outcomes of this study showed that the bioaccumulation levels of both fishery products with low levels of heavy metals are safe for human consumption.

Antibacterial mechanism of slightly acidic electrolyzed water against Pseudomonas arsenicoxydans A1 from greater amberjack (Seriola dumerili)

This study aimed to identify the specific spoilage organism (SSO) from the metamorphosed greater amberjack (Seriola dumerili) fish. Pseudomonas arsenicoxydans A1 was identified as SSO by culture-depending method. Further, the antibacterial efficacy of slightly acidic electrolyzed water (SAEW) was explored and the mechanism of action on P. arsenicoxydans A1 was studied. SAEW with 20–60 mg/L of available chlorine concentration (ACC) showed a good antibacterial effect on P. arsenicoxydans A1. The total number of colonies, growth curve, OD value at 260 nm and 280 nm, DNA fluorescence intensity, alkaline phosphatase (AKP), lactate dehydrogenase (LDH), superoxide dismutase (SOD), and catalase (CAT) enzyme activity and SEM results showed that SAEW could destroy the permeability and integrity of P. arsenicoxydans A1 cell membrane, and affect bacterial cell activity at metabolic, enzymatic and DNA level, which caused bacterial cell death. This study provided the application of SAEW in sterilization and preservation of raw fish fillets, which showed a promising effect on the growth of P. arsenicoxydans A1 in food cold chain.