Polybrominated diphenyl ethers, perfluorinated compounds and chlorinated pesticides in swordfish (Xiphias gladius) from the Mediterranean Sea

The relative isolation of the Mediterranean population, their feeding habits, and the widespread use of their fillets for human consumption make the Mediterranean swordfish, Xiphias gladius, an interesting species from an ecotoxicological and commercial point of views. High resolution gas chromatography and tandem mass spectrometry detected 19 PBDE congeners, perfluorooctane sulfonate (PFOS), and perfluorooctanoic acid (PFOA), hexachlorobenzene (HCB), p,p' and o,p' isomers of DDT, DDE, and DDD in all samples. The presence of PBDEs was reported for the first time in Mediterranean swordfish from the South Tyrrhenian Sea; total PBDE concentrations were 2218 +/- 3291 and 612 +/- 598 pg/g wet wt in the liver and in the muscle, respectively. Significant correlations were identified between BDE47 and sigmaPBDE liver concentrations versus sex and sexual maturity of specimens. The lipid-normalized concentrations ratio BDEn(liver)/BDEn(muscle+liver) suggested that this species mostly accumulates POPs in the liver. PFOS and PFOA were below the LOD (1.5 and 3 ng/g wet wt, respectively) in all the samples. The sigmaDDTs was 155 +/- 125 and 309 +/- 273 ng/g wet wt in the muscle and the liver, respectively. The estimated daily ingestion of PBDEs and DDTs through diet was lower than the acceptable weekly intakes proposed by the World Health Organization.     

HCB, p,p'-DDE and PCB ontogenetic transfer and magnification in bluefin tuna (Thunnus thynnus) from the Mediterranean Sea

The bluefin tuna, Thunnus thynnus (Linnaeus 1758), is biologically and economically important in the Atlantic--Mediterranean ecosystems. Bluefin tuna feed on diverse food items depending on their age, thus they occupy different trophic levels during their lifespan. Hexachlorobenzene (HCB), p,p'-DDE and polychlorinated biphenyls (PCBs) are well-known persistent organic pollutants (POPs) in the Mediterranean basin. The relationship between stable isotopes of nitrogen (N) and the POP residue levels in tissues has recently increased knowledge on the link between the trophic levels and the contaminant accumulation. Trophic levels were estimated by using 15N/14N ratio (delta15N) and HCB, p,p'-DDE, and forty-three PCBs were quantified in bluefin tuna from the southern Tyrrhenian Sea. Results showed that changes in PCB and p,p'-DDE concentrations were a function of size and trophic level, while no correlations were observed for HCB. Apart from HCB and PCB nos. 101, 207, 95, 158, and 60 + 56, which did not show any significant increase per trophic level, the other PCBs and the p,p'-DDE increased significantly. The ontogenetic magnification factor of PCBs was 6.6 +/- 0.5, which was significantly (12 times) higher (p < 0.05) than the values found for p,p'-DDE (1.4) and HCB (1.4).     

Total and organic mercury concentrations in the white muscles of swordfish (Xiphias gladius) from the Indian and Atlantic oceans

A total of 226 swordfish samples collected from Taiwanese fishing vessels in the Indian and Atlantic oceans were examined for total mercury (THg) and organic Hg (OHg). Analysis of 56 pooled white muscle samples showed that THg and OHg concentrations ranged from 0.056 to 3.97 (1.3 ± 0.97) and from 0.043 to 3.92 (1.01 ± 0.82) µg g^-1 flesh mass, respectively. These values were similar to those from various previous studies during the past three decades. THg and OHg were significantly linearly correlated with fork length (FL, cm) of the fish from Indian and Atlantic oceans; however, there was no significant OHg%-FL relationship. OHg and THg also were significantly correlated. Fishes with FL ≤ 140 cm met the methyl Hg (meHg) regulatory standard set by the European Commission Decision (meHg ≤ 1.0); and fish with FL ≤ 211 cm met the Taiwanese Food and Hygiene Standard (meHg ≤ 2.0). Weekly swordfish consumption rates and amounts are recommended accordingly.     

Total mercury in muscle of benthic and pelagic fish from the South Adriatic Sea (Italy).

Total mercury concentrations were measured from the muscle of different kinds of fish: yellow gurnard (Trigla lucerna), red gurnard (Aspitrigla cuculus) red fish (Helicolenus dactylopterus), skate spp. (Raje spp.), goldline (Sarpa salpa), atlantic bonito (Sarda sarda), mackerel (Scomber scombrus), chub mackerel (Scomber japonicus) caught in the South Adriatic Sea (south Italy) in the period June/August 1995. The highest total mercury levels were found in the benthic marine organisms and particularly in skates (Raje spp.) whose values ranged from 0.05 to 2.65 mg/kg wet wt with a mean value of 1.02 mg/kg wet wt. As for pelagic species, the highest mean levels were observed in Atlantic bonito (0.34 mg/kg wet wt), while in goldline the mean content of total mercury was the lowest (0.07 mg/kg wet wt). According to the rules in force (Official Journal of the European Communities 1994) 53% of skate and Atlantic bonito samples showed concentrations exceeding the peak value of 1 mg/kg, while for the other species, only 28% of samples exceeded the peak value fixed at 0.5 mg/kg. Correlations between total mercury concentration and specimen weight were evident in all examined species except for goldline and skates.     

Trial for quality control in mercury contents by using tail muscle of full-cycle cultured bluefin tuna (Thunnus orientalis)

Substantial amounts of mercury are usually present in tuna muscle, with levels in excess of 10 times the standard safety value present in some individuals. Inspection of individual fish for mercury content would be desirable but may not be cost-effective. In this study, we tried to establish a low-cost system for checking the mercury content of tuna by using a tail muscle that is usually discarded. The samples used in this experiment were bluefin tuna, cultured in the Fisheries Laboratory of Kinki University (Oshima Experimental Station, Wakayama, Japan). They were raised from eggs spawned in 2002. Ninety-eight individuals, weighing 22.3 to 61.6 kg, were selected between December 2004 and November 2005. In nine individuals, the mercury content of the tail was compared with that of the whole body. The total mercury level was measured using the reduction vaporizing atomic absorption method after acid digestion. Except for the front of the abdomen, where the mercury content was lower (0.490 ppm), the mercury content of other parts of the fish did not differ from that of the tail muscle (0.631 ppm). Therefore, the overall mercury concentration in bluefin tuna could be estimated to be almost the same and/or lower than that of the tail muscle. On the basis of these results, for 1 year we investigated the quantity of mercury in full-cycle cultured bluefin tuna that were shipped. The mercury concentration showed no increase irrespective of increases of body weight.     

Shelf-life of chilled fresh Mediterranean swordfish (Xiphias gladius) stored under various packaging conditions: microbiological, biochemical and sensory attributes

The present work evaluated the effect of air, vacuum and modified atmosphere packaging (MAP) on the shelf-life of chilled Mediterranean swordfish (Xiphias gladius). Fresh swordfish slices were stored in air, under vacuum and MAP (40%/30%/30%, CO(2)/N(2)/O(2)) under refrigeration (4 degrees C) for a period of 16 days. Of the three treatments used (vacuum, MAP and air), both MAP and vacuum packaging (VP) were the most effective for inhibiting growth of aerobic microflora in swordfish samples until days 9-10 of refrigerated storage. Of the microbial species determined, both Pseudomonas spp. and H(2)S-producing bacteria (including Shewanella putrefaciens) were dominant in swordfish samples stored in air, whereas growth of these species was partly inhibited under VP and MAP conditions. Lactic acid bacteria (LAB) and Enterobacteriaceae were also found to be members of the final swordfish microbial flora, irrespective of packaging conditions throughout the entire storage period. Of the chemical freshness indices determined, thiobarbituric acid (TBA) values were variable in swordfish samples, indicative of no specific oxidative rancidity trend. Trimethylamine nitrogen (TMA-N) values of swordfish samples stored in air, under VP and MAP exceeded the limit value of 5mgN/100g fish muscle after days 7, 8-9 and 11 days of storage, respectively. In a similar trend, total volatile basic nitrogen (TVB-N) for swordfish samples stored in air, under VP and MAP exceeded the limit value of 25mgN/100g fish muscle after 7-8, 10 and 12 days of storage, respectively. Sensory analyses (odor and taste attributes) indicated a shelf-life of ca. 7 days for air, 9 days for VP and 11-12 days for the MA-packaged swordfish samples.     

Mercury and cadmium concentrations in farmed bluefin tuna (Thunnus orientalis) and the suitability of using the caudal peduncle muscle tissue as a monitoring tool

Three regions (cephalic, central, and caudal) of the dorsal and ventral muscle tissue (R1 through R6) and the caudal peduncle muscle tissue (CPMT) of 20 farmed bluefin tuna (Thunnus orientalis) were analyzed for mercury (Hg) and cadmium (Cd) concentrations. Region 1 (cephalic-ventral) had significantly lower concentrations of Hg but significantly higher concentrations of Cd than did the other regions. However, average metal concentrations of all regions (R1 through R6) were only 6% lower for Hg and were not significantly different for Cd from those in the CPMT. Therefore, the CPMT was used to monitor the concentrations of these two metals in more than 100 farmed tuna collected from July 2004 to January 2009 under the assumption that the Cd concentrations in the CPMT would be representative of the Cd concentration in the whole body and that the Hg concentrations would be, in the worst case, overestimated by approximately 6%. The Hg and Cd concentrations in these tuna were inversely related to the condition index, i.e., the tuna in better condition had the lowest concentrations of these metals. The mean concentrations in the CPMT of all fish analyzed were 0.31 ± 0.17 μg/g wet weight for Hg and 0.007 ± 0.006 μg/g wet weight for Cd. These concentrations were below the limits established by Mexican regulations for seafood (1.0 and 0.5 μg/g for Hg and Cd, respectively) and Japan (0.4 μg/g for Hg).     

Content of mercury and cadmium in fish (Thunnus alalunga) and cephalopods (Eledone moschata) from the south-eastern Mediterranean Sea

Mercury and cadmium concentrations were measured in the flesh and liver (or hepatopancreas) of albacore (Thunnus alalunga) and horned octopus (Eledone moschata) to establish whether the concentrations exceeded the maximum levels fixed by the European Commission. In both species, mercury and cadmium mean concentrations were higher in liver (albacore: mercury = 2.41 μg g^-1 wet wt, cadmium = 9.22 μg g^-1 wet wt; horned octopus: mercury = 0.76 μg g^-1 wet wt, cadmium = 6.72 μg g^-1 wet wt) than in flesh (albacore: mercury = 1.56 μg g^-1 wet wt, cadmium = 0.05 μg g^-1 wet wt; horned octopus: mercury = 0.36 μg g^-1 wet wt, cadmium = 0.33 μg g^-1). Mercury concentrations exceeding the prescribed legal limit of 1 μg g^-1 wet wt were found in almost all albacore samples (flesh: 71.4%; liver: 85.7%). For horned octopus, concentrations above 0.5 μg g^-1 wet wt were observed solely in hepatopancreas, while in flesh, the concentrations were below this limit in all the samples examined. Of the flesh samples of albacore, 42.8% exceeded the proposed tolerance for cadmium for human consumption, whilst for horned octopus, the established limit was not exceeded in any sample.     

Structural and ultrastructural changes of full-cycle cultured Pacific bluefin tuna (Thunnus orientalis) muscle slices during chilled storage

Background: This study examined the structural and ultrastructural changes of dorsal and ventral muscle tissues of full‐cycle cultured Pacific bluefin tuna (PBT), Thunnus orientalis Temminck & Schlegel 1844, cut into slices simulating sashimi and placed in chilled storage for varying periods. Structural and ultrastructural changes were determined in order to understand the physical texture by breaking strength measurement. Results: Progressive deterioration of myofibril structure was observed during chilled storage (4 °C) of PBT muscle slices over 5 days post mortem . Muscle degradation included detachment between myofibres, detachment of the plasmalemma, disruption of mitochondria, loss of Z‐line density and alignment, cementation of myofibrils, loss of the hexagonal arrangement of thick versus thin myofilaments and migration of subsarcolemmal nuclei to intermyofibrillar spaces. Conclusion: Loss of myofibre‐myofibre adhesion, detachment of the plasmalemma and disruption of other components did not lower the breaking strength of PBT muscle. This provides evidence that the muscle breaking strength of PBT is not only associated with the detachment of myofibres or detachment of the plasmalemma. Other factors that produce cement‐like substances, such as cementation of the myofibrillar components and degradation of the sarcoplasmic reticulum, may also increase breaking strength. Copyright © 2011 Society of Chemical Industry     

Total, organic, and inorganic arsenic in some commercial species of crustaceans from the Mediterranean Sea (Italy).

Total, organic, and inorganic arsenic were measured in the flesh of different crustacean species: Parapenaeus longirostris, Aristeus antennatus, Plesionika martia, and Nephrops norvegicus, species extensively commercialized and widely consumed as food. Among the different species of crustaceans, the highest mean value of total arsenic was detected in N. norvegicus (45.00 microg g(-1) dry wt), followed by P. martia (40.76 microg g(-1) dry wt), P. longirostris (34.00 microg g(-1) dry wt), and A. antennatus (15.45 microg g(-1) dry wt). In all the species examined, most of this element was present as organic compounds, while inorganic arsenic was only a very modest percentage (3.5 to 5.7%) of the total arsenic present. There is a substantial epidemiological evidence that inorganic arsenic may cause lung and skin cancer. For this reason, the Joint Expert Committee of the FAO-WHO recommended a maximum acceptable daily intake of inorganic arsenic for humans of 2 microg/kg of body weight. The estimated daily intake was below this limit; therefore, no direct hazard for human health due to the consumption of this seafood was found.     

Total mercury and methylmercury content in edible fish from the Mediterranean Sea

The objective of this study was to determine the current levels of total mercury and methylmercury in the muscle tissues of different fish species caught in the Mediterranean Sea to ascertain whether these concentrations exceed the maximum level stipulated by the European Commission Decision. Total mercury concentrations in the muscles of skates ranged from 0.18 to 1.85 mg/kg (wet weight) (average, 1.00 mg/kg) while levels of 0.11 to 1.92 mg/kg (wet weight) (average, 0.70 mg/kg) and 0.21 to 1.74 mg/kg (wet weight) (average, 0.70 mg/kg) were recorded for blue whiting and red mullet, respectively. For 66.7% of long nose skate samples, 61.4% of thornback ray samples, 42.8% of winter skate samples, and 38% of starry ray samples, the total mercury concentrations exceeded the prescribed legal limit (1.0 mg/kg [wet weight]). Concentrations exceeding the maximum total mercury level stipulated by the European Commission Decision (0.5 mg/kg [wet weight]) were observed in 63.6 and 40% of blue whiting and striped mullet samples, respectively. Mercury was present in the different species almost completely in the methylated form at 55 to 100%. Weekly intakes were estimated and compared with the provisional tolerable weekly intake recommended by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives.     

Cadmium and total mercury in some cephalopods from the South Adriatic Sea (Italy)

In the framework of a wide monitoring programme on the presence of heavy metals in marine organisms caught in the South Adriatic Sea, cadmium and total mercury concentrations were determined in flesh and hepatopancreas of 512 specimens of two species of cephalopods. The aim of the study was to establish the quality of the marine food with respect to the health of consumers and to investigate cadmium and mercury distribution in organisms representing different habitats. For both elements, higher levels were found in spider octopus (Octopus salutii) than in broadtail squid (Illex coindeti). Between the two different tissues analysed, higher concentrations were observed in hepatopancreas than flesh. According to the rules in force, no flesh sample showed cadmium and total mercury concentrations exceeding the peak permitted values of 2mg/kgwetwt and 0.5mg/kgwetwt respectively.     

Histological comparison of the dorsal ordinary muscles of wild and full‐cycle cultured Pacific bluefin tuna (Thunnus orientalis)

The histological properties of the cephalad parts of the dorsal ordinary muscles (CD‐OMs) of wild (body weight 33.3 ± 0.9 kg, n = 3) and full‐cycle cultured (body weights 13.1 ± 2.6 (FC 1), 20.2 ± 1.0 (FC 2) and 28.5 ± 3.6 (FC 3) kg, n = 3 respectively) Pacific bluefin tuna were investigated. The CD‐OMs of FC 1–3 tuna showed low moisture content (P < 0.05) and high fat content (about six times more, P < 0.05) in comparison with wild fish. A large quantity of adipose tissue was observed in the wide spaces between muscle fibres in the CD‐OMs of FC 1‐3 tuna. The muscle fibre diameter of the CD‐OM of FC 3 tuna was significantly lower than that of wild fish (P < 0.05). Myofibrils in the CD‐OM of wild tuna were surrounded by a developed sarcoplasmic reticulum and mitochondria; however, there were many glycogen granules among the myofibrils and a large quantity of fat in the CD‐OM of full‐cycle cultured fish. In particular, the glycogen content of the CD‐OM of FC 3 tuna was significantly higher (about 50 times) than that of wild fish. These results indicate that feeding and exercise conditions affect the histological structure and metabolism of the bluefin tuna muscle. Copyright © 2006 Society of Chemical Industry     

Effect of Vacuum and Modified Atmosphere Packaging on the Shelf-life of Liquid-smoked Swordfish (Xiphias gladius) Slices

ABSTRACT: Swordfish fillets, dry-salted and treated with liquid smoke, were sliced and packed in vacuum conditions and under modified atmosphere (MA) (5% O₂,45% CO₂, 50% N₂) and stored at chilled temperature (4°C) to determine the effect of different packaging on shelf-life. Sensory attributes, total volatile basic nitrogen (TVB-N), pH, lipid oxidation by thiobarbituric acid test, and microbiological counts were monitored during 45 d of storage. The TVB-N increased to levels recommended by European regulation at the time of sensory rejection, resulting as the most reliable parameter of quality decay. Lipid oxidation was low and microbial counts could not be correlated with quality decay. Sensory rejection (at least 50% of the assessors scoring =5 in a scale from 1 to 9) was sooner for MA-packed samples (12d) than for vacuum-packed ones (42d).     

Monitoring volatile and nonvolatile amines in dried and salted roes of tuna (Thunnus thynnus L.) during manufacture and storage

Dried and salted roe, obtained from the reproductive organs of female tuna (Thunnus tynnus L.), is a typical fish-based food in the Mediterranean area of Spain. In the present study, we monitored the formation of volatile amines (trimethyamine nitrogen [TMA-N] and total basic volatile nitrogen [TBVN]) and nonvolatile amines (biogenic amines) in dried and salted tuna roe after processing and storage for 8 weeks at 4, 20, and 30 degrees C. The salting and drying process significantly increased the TBVN, cadaverine, tyramine, phenylethylamine, and tryptamine contents, and bacteria with histamine decarboxylase activity were detected both in raw and in dried and salted tuna roes. During storage of tuna roe, TMA-N and TBVN levels increased significantly after the fourth week of storage at 30 degrees C, whereas biogenic amine contents remained more or less constant. However, samples stored at 30 degrees C showed histamine formation after the first week of storage, with a concentration of < 50 ppm. The volatile and nonvolatile amine concentrations in tuna roe were below the consumer safety limit, with the exception of the total biogenic amine level in roe stored at 30 degrees C, which exceeded the European Community's recommended limit (300 ppm). These results indicate that in properly stored tuna roe, histamine formation will not represent a serious health risk to consumers unless the tuna roe has previously been mishandled.     

Evaluation of mercury levels in pangasius and cod fillets traded in Sicily (Italy)

Predator fishes at the top of the aquatic food chain can accumulate large concentrations of metals and their consumption, consequently, makes a significant contribution, in particular, to mercury intake. The aim of this study was to determine mercury levels in fillets of two predatory species: pangasius (Pangasius hypophthalmus) from the Vietnam region of Megong and Chao Pharayai and cod (Gadus morhua) from the Baltic and North Sea, both being commercially important in the Italian market. A comparative analysis of these two imported fish species was carried out as a risk assessment for consumer safety. The results showed the presence of higher mercury levels in pangasius (0.41 ± 0.08 mg kg(-1)) than in cod (0.11 ± 0.004 mg kg(-1)) fillets. These data underline the importance of monitoring on imported fish before marketing, to evaluate better the risk of mercury exposure through fish and seafood consumption, and of selecting safer fishes for consumption by those groups more sensitive to the toxic effects of this metal.     

Evaluation of mercury levels in Pangasius and Cod fillets traded in Sicily (Italy)

Predator fishes at the top of the aquatic food chain can accumulate large concentrations of metals and their consumption, consequently, makes a significant contribution, in particular, to mercury intake. The aim of this study was to determine mercury levels in fillets of two predatory species: pangasius (Pangasius hypophthalmus) from the Vietnam region of Megong and Chao Pharayai and cod (Gadus morhua) from the Baltic and North Sea, both being commercially important in the Italian market. A comparative analysis of these two imported fish species was carried out as a risk assessment for consumer safety. The results showed the presence of higher mercury levels in pangasius (0.41?±?0.08?mg?kg^?1) than in cod (0.11?±?0.004?mg?kg^?1) fillets. These data underline the importance of monitoring on imported fish before marketing, to evaluate better the risk of mercury exposure through fish and seafood consumption, and of selecting safer fishes for consumption by those groups more sensitive to the toxic effects of this metal.     

Analysis and risk assessment of arsenic,cadmium and lead in two fish species (Sardina pilchardus and Xiphias gladius) from Algerian coastal water

ABSTRACT

In this study, the levels of arsenic (As), cadmium (Cd) and lead (Pb) have been determined in the flesh of two species of fish, sardine (Sardina pilchardus) and swordfish (Xiphias gladius) fished in the Algerian coast. Quantification of As, Cd and Pb was carried out using an ICP-MS method and the results were compared with the thresholds set by national and international regulatory bodies. In a further step, the risk to consumers was assessed using estimated daily intake (EDI), target hazard quotient (THQ) and hazard index (HI).The average concentration of As and Pb was higher in sardine (1.82; 0.10 mg kg^?1 w.w., respectively), than in swordfish (1.10 mg kg^?1 w.w.; not determined), whereas the concentration recorded for Cd was the same for both species (0.01 mg kg^?1 w.w.). These concentrations are below maximum limits set in regulations. The THQs and HI were widely below 1. The consumption of these fish does not pose risk to the consumers.     

Correlation of fat content and dioxins, total mercury and methyl mercury levels in tuna

In this study, we analyzed the concentrations of mercury and dioxins in tuna with various fat contents (akami; the leaner meat, Chutoro; the belly area of the tuna along the side of the fish between the akami and the otoro. Otoro; the fattiest portion of the tuna) in wild and farmed bluefin tuna and farmed southern bluefin tuna. In the three kinds of tuna, average dioxins concentrations in Akami, chutoro and otoro were 1.7, 4.7 and 9.6 pg TEQ/g, respectively. The dioxins concentration in all three regions of tuna was in direct proportion to the fat content. In the farmed bluefin tuna, the dioxins concentration was almost the same as that of the wild tuna, but differed from that of the farmed southern bluefin tuna. Average total mercury concentration based on wet weight in akami was 0.42 μg/g, being higher than the values of 0.36 μg/g of chutoro and 0.31 μg/g of otoro, and in inverse proportion to the fat content. In all three regions, the total mercury concentration of the wild bluefin tuna was equal to that of the farmed tuna. The total mercury concentration in the latter was two to three times higher than that of the farmed southern bluefin tuna. If the Japanese intake is one fin of tuna (80 g) a day, the daily intake levels of dioxins and methyl mercury can be estimated as 0.48-37 pg TEQ/kg bw and 0.21-0.90 μg/kg bw, respectively.     

Bioactive properties of enzymatic hydrolysates from abdominal skin gelatin of yellowfin tuna (Thunnus albacares)

Gelatin (90.6 ± 0.1%) was optimally prepared by response surface methodology from yellowfin tuna (Thunnus albacares, YT) abdominal skin. To investigate bioactive properties of enzymatic hydrolysates from the abdominal skin gelatin (ASG), ASG was hydrolysed with alcalase, protamex, neutrase and flavourzyme as affected by hydrolysis time. Antioxidant, nitrite scavenging and angiotensin‐I converting enzyme (ACE) inhibitory activities of the hydrolysates were determined. Antioxidant activities of the hydrolysates were found through linoleic acid peroxidation inhibitory effects. Alcalase‐derived hydrolysates (AHs) were more effective than others in metal ions chelating, superoxide anion scavenging and hydroxyl radical scavenging activities (P < 0.05). AHs showed significantly stronger nitrite scavenging activities (44.4–60.7%) than others (P < 0.05). Fraction A from AH showed strong ACE inhibitory activity (IC₅₀ of 0.75 mg mL^?1). These results suggest that YT ASG and its enzymatic hydrolysates could be functional food and/or pharmaceutical ingredients with potent antioxidant, anticarcinogenic and antihypertensive benefits.