Evaluation of biotoxins and toxic metal risks in mussels from the Sea of Marmara following marine mucilage.

The mucilage phenomenon observed in the Sea of Marmara in 2021, has raised public concern about seafood safety. Mediterranean mussels serve as a vehicle in food chain, enabling the transfer of pollutants. Farmed and wild mussels were collected from 4 different stations throughout the fishing season. Biotoxins causing amnesic, paralytic, or diarrhetic shellfish poisonings (ASP, PSP, or DSP) were examined during monthly samplings. Potential health risks posed by cadmium, lead and arsenic were assessed. Health risks were evaluated considering 150 g/week mussel consumption, accounting for the different age groups of consumers (50, 60, 70 kg). Estimated Weekly Intake calculations of metals were determined to be lower than Provisional Tolerable Weekly Intake at all age groups throughout the sampling period in all stations. Target Hazard QuotientCd of mussels captured from Istanbul Strait was always determined <1, while it was equal to 1 for 50 kg individuals in Gelibolu samples. All THQAs were >1. Target carcinogenic Risk was evaluated for Pb and iAs, which were found to be negligible and acceptable, respectively. No biotoxins responsible for ASP, PSP, or DSP were detected. Hg levels were under detectable limits. Excluding Cd, the results did not reveal any risks associated with mussel consumption during mucilage.

Evaluation of Health Risks Attributed to Toxic Trace Elements and Selenium in Farmed Mediterranean Mussels from Türkiye and Bulgaria.

Farmed mussels accumulate contaminants from their production environment rather than releasing them into water. This study reveals potential health risks associated with selenium, cadmium, mercury, and lead resulting from the consumption of mussels (Mytilus galloprovincialis) cultured along the coasts of Türkiye and Bulgaria. The concentrations of Se and toxic trace metals were measured by inductively coupled plasma mass spectrometry (ICP-MS). The detection limits (LOD) were 0.100, 0.015, 0.025, and 0.180 µg/kg for Se, Cd, Hg, and Pb, respectively. The mean Se concentrations were between 1.305 and 1.957 µg/g, and toxic metals were below the maximum limits. Due to Turkish and Bulgarian consumers' limited mollusk consumption, mussels could only provide a maximum of 7.35% of the daily Se need. THQ and TTHQ of Se, Cd, and methyl-Hg were below 1, indicating that farmed mussels were safe for consumption. Percent PTWI values were calculated only for Cd and MeHg, as the PTWI value for Pb was discarded by the authorities and not determined for Se. Accordingly, weekly mussel consumption did not pose any risks. The margin of exposure approach was used to evaluate Pb intake. MOE-SBP and MOE-NE were significantly higher than 10, designating no significant health risks. Long-term consumption of mussels also does not pose a carcinogenic risk regarding the TR index calculated between 10-5 and 10-6 for Pb. Positive HBVSe (10.13-37.27) indicated that Se in mussels overcame Hg-related potential health concerns. Consequently, mussels grown in Türkiye and Bulgaria did not pose a risk for human consumption, based on current risk analysis methods.

Trace elements in seabass, farmed by Turkey, and health risks to the main consumers: Turkish and Dutch populations.

Turkey ranked first in sea bass farming in Europe, and almost all extra-EU seabass come from this country. The share of Turkish sea bass in the fish consumption of Europeans has increased significantly, and assessment of potential health risks of trace metals via sea bass, cultured by Turkey, became important. The Netherlands is the main buyer of the Turkish sea bass. Therefore, potential health risks were determined for Turkish and Dutch consumers. In the study, the concentrations of lead (Pb) and mercury (Hg) were below the limits, but the level of cadmium (Cd) was above the guidelines, in spring and winter. Dietary intake and potential health risk were found higher for the Dutch consumer, but all target hazard quotients (THQs) and total THQ (TTHQ) values were well below 1, showing no significant health risk due to the consumption of sea bass, cultured and exported by Turkey. It was determined that these sea basses can be safely consumed in quite high amounts, such as at least 31 meals a month. Se/Hg molar ratios were all above 1 and selenium health benefit values (Se-HBVs) were positive, indicating that selenium (Se) had a protective effect on Hg toxicity and positive health effects. Considering the average annual intake in Turkey and Netherlands, the consumption of sea bass, cultured by Turkey, is safe. Since the risk levels of communities may differ due to their eating habits, it is important to determine the public health impacts of the international fish trade.

Increased thermal sensitivity of Listeria monocytogenes in sous-vide salmon by oregano essential oil and citric acid.

Inadequate cooking during sous-vide processing may cause foodborne diseases in case the food is contaminated with pathogens such as Listeria monocytogenes. In this study, thermal inactivation of L. monocytogenes in sous-vide processed salmon was investigated. Oregano oil and citric acid were used alone or in combination to determine the probability of increasing the efficiency of heat treatment. Control (C); 0.5% citric acid added (S); 1% oregano essential oil added (O); and citric acid and oregano essential oil combined (OS) groups were prepared. Samples were inoculated with L. monocytogenes, vacuum packed, then sous-vide cooked at 55, 57.5, 60, or 62.5 °C for predetermined times. The D-values of all treated samples were significantly lower than control. The use of oregano oil (O), citric acid (S) and their combination (OS) significantly reduced the time required to inactivate L. monocytogenes. The z-values of L. monocytogenes in C, O, S and OS groups were 5.50, 5.62, 6.54, and 6.92 °C, respectively. It was determined that effective results could be achieved by adding natural antimicrobials to provide safety in sous-vide fish.

Selenium-Mercury Balance in Commercial Fish Species from the Turkish Waters.

The interactions between selenium (Se) and mercury (Hg) were assessed in order to interpret public health risk, associated with dietary mercury exposure due to fish consumption. For this purpose, the mass and molar concentrations of Se and Hg were determined in the edible tissues of six species of fish, collected from the commercial fishing grounds of Turkey. The Se/Hg molar ratios and selenium health benefit values (Se-HBVs) were also calculated. The main fish species exported from Turkey to Europe were studied to determine the risks or benefits for human health. The mean Hg levels (µg g-1, wet weight) ranged from 0.01 (in turbot) to 0.45 (in Atlantic bluefin tuna). The average selenium concentrations were between 0.96 µg g-1 (in thornback ray) and 1.86 µg g-1 (in turbot). The molar ratios of Se/Hg were above 1 for all species and greater than 100 in turbot, red mullet, and whiting. Positive Se-HBVs were determined for all samples, showing health benefits. Since Se is present in molar excess of Hg in the fish muscles, organic Hg exposures from eating these fish is not a public health concern.

A new measurement approach of ionizing radiation in irradiated trout (Oncorhynchus mykiss) by Randomly Polymorphic DNA-Polymerase Chain Reaction.

Trout (Oncorhynchus mykiss) were irradiated at doses of 0.250, 0.500, 1, 3, 5, 7 and 9 kGy in gamma cell. DNAs were extracted from the irradiated samples before and after storage. 1ERP primers were designed, and RAPD-PCR (Randomly Polymorphic DNA-Polymerase Chain Reaction) was applied to make randomly amplifications on the DNA of the irradiated samples. Agarose gel profiles of irradiated fish were obtained to determine change of band profiles. In addition, DNA fragmentation occurring in each dose was determined by comet assay for the verification of methodology developed in this study. The molecular methodology was developed to estimate ionizing radiation (IR) level in irradiated fish. This methodology allows the analysis of the trout irradiated up to the dose limit of around 0.5 kGy and stored for a period of three months.

Determination of irradiation dose and distinguishing between irradiated and non irradiated fish meat by real-time PCR.

In this study, the effects of gamma irradiation on the DNA of fish (Oncorhynchus mykiss) by real-time PCR were studied. Fish (O. mykiss) were exposed to radiation doses of 0.250, 0.500, 1, 3, 5, 7, and 9 kGy in a gamma cell. Primers were designed for regions with different lengths of both nuclear and mitochondrial DNA, and each primer was used to amplify the DNA from irradiated samples. The amplicon curves for mitochondrial and nuclear DNA, and the correlations among the curves, were obtained. The Ct values for a 519 bp region of the 18S RNA gene on nuclear DNA correlated appropriately. Radiation doses applied to the fillets were estimated using the standard curve data obtained from the correlation values, and the DNA damage caused by each dose was calculated. As a consequence, a molecular methodology to analyze irradiated fish meat qualitatively and also for the estimation of administered dose was developed. This method allowed analysis of irradiated fish, which had been stored for up to 3 months with a dose limit of approximately 0.5 kGy.

Levels of heavy metals in canned bonito, sardines, and mackerel produced in Turkey.

Concentrations of selected metals were determined using ICP-MS in canned bonito, sardines and mackerel commercialized in Turkey. Thirty samples and two different brands were sampled for each fish species. The minimum and maximum concentrations of trace metals in canned bonito, sardines and mackerel were found as 0.000-34.742, 0.000-89.015, 0.000-28.725 mg/kg for iron, 2.388-26.620, 10.930-41.340, 4.778-29.270 mg/kg for zinc, 0.331-1.548, 0.599-2.242, 0.336-2.884 mg/kg for copper, 0.000-0.065, 0.000-0.113, 0.000-0.115 mg/kg for cadmium, 0.000-0.190, 0.000-0.158, 0.000-0.385 mg/kg for tin, 0.000-0.111, 0.000-0.223, 0.000-0.208 mg/kg for mercury and 0.000-3.046, 0.000-2.875, 0.000-3.529 mg/kg for lead, respectively. These levels are similar those found in other studies. Although the samples have concentrations within permissible limits for Zn, Cu, Sn and Hg, some of them contained Fe, Cd and Pb above these limits. Periodical controls of metals in canned fish are essential both to protect human health and to provide data on this subject.

Determination of trace metals in canned anchovies and canned rainbow trouts.

Trace metal (Fe, Zn, Cu, Cd, Sn, Hg and Pb) concentrations of canned anchovies (Engraulis encrasicolus Linnaeus, 1758) and canned rainbow trouts (Oncorhynchus mykiss Walbaum, 1792), commercialized in Turkey, were determined using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). The average contents of trace metals in canned anchovies and canned rainbow trouts were found as 50.708 and 6.980 mg/kg for iron, 22.467 and 11.605 mg/kg for zinc, 1.145 and 0.541 mg/kg for copper, 0.019 and 0.001 mg/kg for cadmium, 0.140 and 0.023 mg/kg for tin, 0.041 and 0.026 mg/kg for mercury, and 0.188 and 0.167 mg/kg for lead, respectively. Although these products pose no risk with respect to the concentrations of zinc, copper, cadmium, tin and mercury, some of the samples had higher contents of lead and iron than the permissible limits. Comprehensive and periodic controls of trace metals in canned fish are needed to assess the safety of these products with respect to human health.

Heavy metals in mussels (Mytilus galloprovincialis) from Marmara sea, Turkey.

Marmara Sea is one of the main catching areas of mussels (Mytilus galloprovincialis) in Turkey, and a significant portion of the harvest has been exported mainly to European countries. In this study, Zn, Cu, Cd, Hg, and Pb in mussels from ten catching areas in Marmara Sea were analyzed to investigate health risks associated with consuming mussels. Mercury was not detected (<0.15 ppb) in any of the samples. The highest concentrations of Cu and Cd were 3.473 and 0.740 mg kg(-1) (wet weight, WW), respectively, well below the maximum permissible levels. All samples contained Zn higher than 50 mg kg(-1), while Pb was above the limits in the samples from stations 1, 4, 6, and 8. Mussels from Marmara Sea are safe regarding Cu, Cd, and Hg but may contain Zn and Pb above the permissible limits. However, metal contents of mussels from Marmara Sea are mostly lower than those of the regions in other areas of the world. It was concluded that Marmara Sea has a potential of being a safe source of mussels if industrial inputs somewhat reduced and controlled. Concentrations of heavy metals in mussels must be monitored comprehensively and periodically with respect to the consumer health.

Survival of Salmonella Enteritidis during salting and drying of horse mackerel (Trachurus trachurus) fillets.

Survival of Salmonella Enteritidis inoculated (5-6 log cfu/g) on horse mackerel fillets was studied during salting and/or drying processes at 4 degrees C for up to 70days. Sample groups were as follows: group A (salt/fish=80/100), group B (salt/fish=30/100), group C (salted as group A and dried after 15days), group D (salted as group B and dried after 15days), and group E (dried without salting). The salt content increased in all groups with a maximum level of 29.36%. Final salt contents (%) were higher (P<0.05) in salted-dried groups (C and D) than the salted groups (A and B). Total reductions in a(w) values were found as group E>group D>group C>groups A and B (P<0.05). Salmonella survived 60days in group A, 65days in group B, 35days in group C, 45days in group D and 20days in group E. Drying process following salting accelerated the elimination of this pathogen. Salmonella survived longer in salted samples than in salted-dried and dried samples. This work demonstrated that Salmonella may be inhibited by one of salting, drying and salting-drying techniques; however, processing periods should be long enough to reduce a(w) sufficient to inhibit this pathogen.