Effects of various cooking processes on the concentrations of arsenic, cadmium, mercury, and lead in foods

Mercury concentration in shark meat from traditional markets of Gyeongsangbuk-do, South Korea

Background

Although unusually high levels of blood mercury have been reported in the North Gyeongsang Province (Gyeongsangbuk-do), mercury contents from shark meat distributed in this region have not been assessed yet. Thus, this study aims to identify the hazard by evaluating the mercury contents of the shark meat sold in the traditional market of Gyeongsangbuk-do.

Methods

The shark meat in the form of muscle meat was obtained from 15 traditional markets of Gyeongsangbuk-do in the summer and winter of 2013. Out of 105 samples in total, 49 were collected in the summer and 56 in the winter. The total mercury concentration was measured by the combustion-gold amalgamation method using an automatic mercury analyzer (Milestone DMA-80, Milestone).

Results

The average mercury concentration of shark meat was 2.29 ± 1.77 µg/g, ranging between 0.06–8.93 µg/g with a geometric mean of 1.44 µg/g, which is higher than those reported in many countries. The mercury concentration in 77 of 105 shark meat samples exceeded 1 µg/g. Mercury concentration ranged between 0.09–8.93 µg/g (geometric mean: 1.45) in the summer and 0.06–6.73 µg/g (geometric mean: 1.48) in the winter.

Conclusions

Shark meat sold in the market contained a substantial amount of mercury. This suggests that it is difficult to reduce mercury intake by simply strengthening the standard level of mercury concentration in shark meat. Therefore, it is need to communication and awareness programs with consumers about hazardous effects of mercury inherent in shark meat.

Effects of four cooking methods on sensory and taste quality of Portunus trituberculatus

The effect of heating medium (with water and steam) and initial temperature of heating medium (cold and boiling) on the taste quality and sensory properties of Portunus trituberculatus was investigated. Nonvolatile taste active components in the meat and gonad of crabs cooked under four different methods were detected and compared. Sensory evaluation and electronic tongue assessment were also conducted. Sensory evaluation and electronic tongue indicated that taste quality was different under four cooking methods. The results showed that steaming cooking preserved more water-soluble substances as compared with boiling cooking, especially cooking began with boiling water. It is noteworthy that the umami intensity in gonad cooked from boiling water was stronger, either steaming or boiling. Therefore, this study can provide a theoretical basis and suggest the dynamic chemical changes of different organs during heating process need to be further studied.

Occurrence, behaviour, and human exposure pathways and health risks of toxic geogenic contaminants in serpentinitic ultramafic geological environments (SUGEs): A medical geology perspective

Serpentinitic ultramafic geological environments (SUGEs) contain toxic geogenic contaminants (TGCs). Yet comprehensive reviews on the medical geology of SUGEs are still lacking. The current paper posits that TGCs occur widely in SUGEs, and pose human health risks. The objectives of the review are to: (1) highlight the nature, occurrence and behaviour of TGCs associated with SUGEs; (2) discuss the human intake pathways and health risks of TGCs; (4) identify the key risk factors predisposing human health to TGCs particularly in Africa; and (5) highlight key knowledge gaps and future research directions. TGCs of human health concern in SUGEs include chrysotile asbestos, toxic metals (Fe, Cr, Ni, Mn, Zn, Co), and rare earth elements. Human intake of TGCs occur via inhalation, and ingestion of contaminated drinking water, wild foods, medicinal plants, animal foods, and geophagic earths. Occupational exposure may occur in the mining, milling, sculpturing, engraving, and carving industries. African populations are particularly at high risk due to: (1) widespread consumption of wild foods, medicinal plants, untreated drinking water, and geophagic earths; (2) weak and poorly enforced environmental, occupational, and public health regulations; and (3) lack of human health surveillance systems. Human health risks of chrysotile include asbestosis, cancers, and mesothelioma. Toxic metals are redox active, thus generate reactive oxygen species causing oxidative stress. Dietary intake of iron and geophagy may increase the iron overload among native Africans who are genetically predisposed to such health risks. Synergistic interactions among TGCs particularly chrysotile and toxic metals may have adverse human health effects. The occurrence of SUGEs, coupled with the several risk factors in Africa, provides a unique and ideal setting for investigating the relationships between TGCs and human health risks. A conceptual framework for human health risk assessment and mitigation, and future research direction are highlighted.

Evaluation of the influence of different cooking pot types on the metallic elements content in edible chicken tissues by MIP OES

Abstract This work describes the analysis of different chicken tissues (gizzard, heart, and liver) both raw and cooked with seasonings in different types of cooking pots (iron pot, , aluminum pot and hammered aluminum pot) commonly used in Brazil. The samples were decomposed using microwave-assisted digestion with diluted nitric acid; and the contents of Al, Ca, Cu, Fe, Mn and Ni were determined using Microwave Induced Plasma Optical Emission Spectrometry (MIP OES). The Fe content was also determined by Flame Atomic Absorption Spectrometry, and the comparison showed good accuracy of the method. The limits of quantification were below 0.011 mg kg-1, showing adequate detectability. Cooking in the different pots increased the ash and protein contents as well as decreased the moisture content. Box-plot and Principal Components Analysis showed that Ca and Fe contents present the largest variations in the samples, followed by Al and moisture. The variables Al, Cu, Mn, Ni, ash, and protein presented similar behavior after cooking in all different pots. In addition, liver cooked in both iron and hammered aluminum pots presented similar Fe contents, while gizzard and heart showed similar Ca contents.

Food safety risk assessment of metal pollution in crayfish from two historical mining areas: Accounting for bioavailability and cooking extractability

Here we characterize the bioaccumulation of mercury (Hg) and lead (Pb) in red swamp crayfish (Procambarus clarkii) from two river courses in Central Spain that are impacted by historical Hg and Pb mining activities, respectively. We estimate the absolute oral bioavailability of metals in crayfish tissues by means of in vitro bioaccessibility simulations, and assess whether their consumption may imply a health risk for humans by estimating target hazard quotients and safe consumption rates. We also study the effect of cooking crayfish on the mobilization of the metal body burden in the context of the traditional Spanish cuisine. The results showed that crayfish from the mining districts accumulated a high level of Hg and Pb pollution in both the tail muscle and the carcass. The in vitro bioaccessibility of Hg and Pb in the edible part was 27.86 ± 4.05 and 33.73 ± 5.91%, respectively. Absolute bioavailability was estimated to be 38.31 for Hg, and 20.21 (adults) and 67.35% (children) for Pb. Risk indices indicated that, even after adjusting for bioavailability, it is not safe to consume crayfish from the mining-impacted rivers because of their high levels of Hg and Pb. Using the carcass as a condiment for flavouring should also be avoided. The cooking procedure extracted relatively small amounts of the total Hg (8.92 ± 2.13%) and Pb (1.68 ± 0.29%) body burden. Further research that will support human and ecological risk assessment, along with the implementation of advisory measures for the local population as regards crayfish consumption, are recommended.

Does the addition of ingredients affect mercury and cadmium bioaccessibility in seafood-based meals?

Despite the bioaccessibility of nutrients and contaminants present in individual seafood products has been thoroughly studied, information is extremely limited in what concerns complete seafood-based meals, where interactions between ingredients may occur. Hence, this study aimed to evaluate the effect of different ingredients and cooking processes in mercury (Hg) and cadmium (Cd) bioaccessibility in complete meals of tuna (Thunnus spp.) and edible crab (Cancer pagurus), respectively. The addition of ingredients/side dishes decreased Hg levels in cooked tuna meals, but increased Hg bioaccessibility (up to 31% of bioaccessible Hg in complete meals, against 13.5% in stewed tuna alone). Cd levels in edible crab meals were significantly decreased by the addition of ingredients (~36% and ~65% decrease in boiled crab and paté, respectively), but its' bioaccessibility was not significantly affected (>94% in all cases). Results showed that the weekly consumption of 2 complete tuna meals does not exceed MeHg tolerable weekly intake (TWI), whereas Cd's TWI is largely surpassed with the consumption of 50 g/week of edible crab meals. This highlights the importance of determining contaminant levels and bioaccessibility in a whole seafood-based meal context, as such approach enables a more realistic assessment of the risks that seafood can pose to consumers.

Change in mercury speciation in seafood after cooking and gastrointestinal digestion

Mercury (Hg) is readily bioaccumulated in seafood, a common ingredient in indigenous cuisines throughout the world. This study investigates Hg speciation in cooked seafood after gastric and intestinal digestion. The results showed that the removal of Hg by washing was negligible. Additionally, the results of our calculations regarding the mass balance of Hg concentration indicated that cooking reduced Hg mainly by means of volatilization and that Hg²⁺ was more readily reduced than MeHg. Moreover, cooking lowered the bioaccessibility of Hg in seafood: the reduced percent of bioaccessible Hg²⁺ after cooking ranged from 2 to 35% (on average, 16%). The corresponding numbers were slightly lower compared with those for MeHg (on average, 19%). Furthermore, there might be a chemical transformation of Hg during in vitro gastrointestinal digestion. The results of in vivo tests in laboratory mice suggested that methylation of Hg mainly took place in the gastric tract, whereas demethylation of Hg occurred primarily during intestinal digestion. These findings indicate that the bioaccessibility of Hg²⁺ and MeHg was not only related to their initial concentrations in the food samples, but also that further studies on the mechanisms of Hg demethylation and methylation during gastrointestinal digestion are essential for more realistic risk assessments.

Mercury Exposure in Mother-Children Pairs in A Seafood Eating Population: Body Burden and Related Factors

Background: Mercury is a neurotoxin that affects neurodevelopment in children; however, its association at the lowest concentration is not clear. The main objective of this study is to measure and evaluate mercury concentrations in mother–child pairs and its association demographics, lifestyle, and dietary factors within the Pacific Island Families living in Auckland, New Zealand. Methods: Mercury exposure was assessed in a sub-sample of mother–child pairs who were a part of the Pacific Island Families birth cohort, in Auckland, New Zealand at the 6-year phase. Hair samples were collected from both mothers and their children to determine mercury concentrations. Total mercury was measured using inductively coupled plasma mass spectrometry for hair samples. An interviewer-based reliable food frequency questionnaire (FFQ) examined the frequency of seafood by all the participants. Other variables such as sociodemographic (ethnicity and gender), lifestyle factors (income, education, and smoking status) and health outcomes (child behaviour and obesity) were also collected. Results: In this study, 41% of both mothers and their children had mercury concentrations above the US Environmental Protection Agency (EPA) recommended value of 1 µg/g. Most of the participants ate fish 3 or more times a week. A significant correlation was observed between mother and child hair mercury concentrations (Spearman Rho 0.79 (95% confidence interval (CI): 0.65, 0.88)). Conclusions: Mercury levels in children can be affected by their mothers’ levels due to similar eating patterns.

Arsenic in cooked rice foods: Assessing health risks and mitigation options

Human exposure to arsenic (As) through the consumption of rice (Oryza sativa L.) is a worldwide health concern. In this paper, we evaluated the major causes for high inorganic As levels in cooked rice foods, and the potential of post-harvesting and cooking options for decreasing inorganic As content in cooked rice, focusing particularly on As endemic areas. The key factors for high As concentration in cooked rice in As endemic areas are: (1) rice cultivation on As-contaminated paddy soils; (2) use of raw rice grains which exceed 200 μg kg^-1 of inorganic As to cook rice; and (3) use of As-contaminated water for cooking rice. In vitro and in vivo methods can provide useful information regarding the bioaccessibility of As in the gastrointestinal tract. Urinary levels of As can also be used as a valid measure of As exposure in humans. Polishing of raw rice grains has been found to be a method to decrease total As content in cooked rice. Sequential washing of raw rice grains and use of an excess volume of water for cooking also decrease As content in cooked rice. The major concern with those methods (i.e. polishing of raw rice, sequential washing of raw rice, and use of excess volume of water for cooking rice) is the decreased nutrient content in the cooked rice. Cooking rice in percolating water has recently gained significant attention as a way to decrease As content in cooked rice. Introducing and promoting rainwater harvesting systems in As endemic areas may be a sustainable way of reducing the use of As-contaminated water for cooking purposes. In conclusion, post-harvesting methods and changes in cooking practices could reduce As content in cooked rice to a greater extent. Research gaps and directions for future studies in relation to different post-harvesting and cooking practices, and rainwater harvesting systems are also discussed in this review.

Assessment of individual-based perfluoroalkly substances exposure by multiple human exposure sources

Individual exposure of perfluoroalkyl substances (PFASs) was assessed by analyzing serum, food, dust, drinking water, and hand wipes from 50 individuals. The PFASs concentrations in serum were correlated most strongly with exposure to PFASs through the (direct and indirect) ingestion of dust (p <  0.01). Daily PFOA intakes were estimated to be 2.07 ng/kg/day from food, 0.003 ng/kg/day from dust, 0.053 ng/kg/day from hand-to-mouth activity, and 0.020 ng/kg/day from drinking water. Daily perfluorooctanesulfonic acid (PFOS) intakes were estimated to be 0.689 ng/kg/day from food, 0.001 ng/kg/day from dust, 0.018 ng/kg/day from hand-to-mouth activity, and 0.005 ng/kg/day from drinking water. The daily PFOA and PFOS intakes calculated for individuals in this study and in group/scenario based exposure assessment of previous studies were compared. The estimated PFOS intake on individual basis (0.695 ng/kg/day) was a little bit higher than the intake on group/scenario basis (0.652 ng/kg/day). However, the estimated daily PFOA intake on individual basis (1.41 ng/kg/day) was about four times higher than the intake on group/scenario basis (0.339 ng/kg/day). Among the exposure pathways, food ingestion was major contributor to the total daily PFOA and PFOS intakes on individuals (99% of total intake) and group/scenario basis (64% of total intake).

Effect of Cooking on Speciation and In Vitro Bioaccessibility of Hg and As from Rice, Using Ordinary and Pressure Cookers

Rice is the most widely consumed staple food for a large part of the world's human population, and owing to environmental pollution, it is a major source of human exposure to mercury (Hg) and arsenic (As). We evaluated the impact of cooking on the speciation and bioaccessibility of Hg and As from rice in this study. Results show that the dominant Hg and As species in rice from Guangzhou market in China were their inorganic forms (iHg and iAs), respectively. The cooking process modified the levels of Hg and As. Average Hg and As bioaccessibility in raw rice was 69.74 and 80.32%, respectively. Hg bioaccessibility decreased to 46.22 and 42.37% for pressure- and ordinary-cooked rice, respectively. In contrast, As bioaccessibility remained unchanged except after cooking with a large amount of water. Protein denaturation and the amount of soluble and volatile forms determine the bioaccessibility of Hg and As in cooked rice by being released into the cooking water or into the air. From the bioaccessibility data, the average established daily intake (EDI) values of Hg and As from pressure-cooked rice for children and adults were 0.034 and 0.025 μg kg^-1 day^-1 (Hg), and 0.735 and 0.559 μg kg^-1 day^-1 (As), respectively. This study provides novel insights into Hg and As exposure due to rice cooking.

Change of Arsenic Speciation in Shellfish after Cooking and Gastrointestinal Digestion

Shellfish is a common part of indigenous cuisines throughout the world and one of the major sources of human exposure to arsenic (As). We evaluated As speciation in shellfish after cooking and gastrointestinal digestion in this study. Results showed that washing and cooking (boiling and steaming) can reduce As exposures from shellfish. The use of spices during cooking processes also helped to reduce the bioaccessibility of total As. Through mass balance calculations, we verified the transformation of methylated As compounds into inorganic As in shellfish takes place during cooking and that As demethylation can occur during simulated gastrointestinal digestion. In vivo demethylation of As after gastrointestinal digestion was also demonstrated in laboratory mice. This increase in inorganic As during digestion suggests that risks of As toxicity from shellfish consumption are being underestimated. Further studies on the mechanisms of As speciation transformation in food are necessary for more thorough risk assessments.

In Vitro Model To Assess Arsenic Bioaccessibility and Speciation in Cooked Shrimp

Shrimp, a popular and readily consumed seafood, contains high concentrations of arsenic. However, few studies have focused on whether arsenic in the shrimp could be transformed during the cooking process and gastrointestinal digestion. In this study, a combined in vitro model [Unified Bioaccessibility Research Group of Europe (BARGE) Method-Simulator of Human Intestinal Microbial Ecosystem (UBM-SHIME)] was used to investigate arsenic bioaccessibility and its speciation in raw and cooked shrimps. The results showed that the cooking practices had little effect on the arsenic content and speciation. Bioaccessibility of arsenic in raw shrimp was at a high level, averaging 76.9 ± 4.28 and 86.7 ± 3.74% in gastric and small intestinal phases, respectively. Arsenic speciation was stable in all of the shrimp digestions, with nontoxic arsenobetaine (AsB) being the dominated speciation. The cooking practice significantly increased the bioaccessibility of arsenate ( p < 0.05) in shrimp digests, indicating the increase of the potential health risks.

Multielement analysis of Zanthoxylum bungeanum Maxim. essential oil using ICP-MS/MS

The concentrations of trace elements (Cr, Ni, As, Cd, Hg, and Pb) in Zanthoxylum bungeanum Maxim. essential oil (ZBMEO) were determined by inductively coupled plasma tandem mass spectrometry. The ZBMEO sample was directly analyzed after simple dilution with n-hexane. Aiming for a relatively high vapor pressure of n-hexane and its resultant loading on plasma, we used a narrow injector torch and optimized plasma radio frequency power and carrier gas flow to ensure stable operation of the plasma. An optional gas flow of 20% O₂ in Ar was added to the carrier gas to prevent the incomplete combustion of highly concentrated organic carbon in plasma and the deposition of carbon on the sampling and skimmer cone orifices. In tandem mass spectrometry mode, O₂ was added to the collision/reaction cell to eliminate the interferences. The limits of detection for Cr, Ni, As, Cd, Hg, and Pb were 2.26, 1.64, 2.02, 1.35, 1.76, and 0.97 ng L^-1, respectively. After determination of 23 ZBMEO samples from different regions in China, we found that the average concentration ranges of trace elements in the 23 ZBMEO samples were 0.72-6.02 ng g^-1, 0.09-2.87 ng g^-1, 0.21-5.84 ng g^-1, 0.16-2.15 ng g^-1, 0.13-0.92 ng g^-1, and 0.17-0.73 ng g^-1 for Cr, Ni, As, Cd, Hg, and Pb, respectively. The trace elements in ZBMEO differed significantly when different extraction technologies were used. The study revealed that the contents of the toxic elements As, Cd, Hg, and Pb were extremely low, and hence they are unlikely to pose a health risk following ZBMEO ingestion. Graphical abstract The working mechanism of sample analysis by ICP-MS/MS.

Portuguese preschool children: Benefit (EPA+DHA and Se) and risk (MeHg) assessment through the consumption of selected fish species

This study aimed to assess the risk-benefit balance associated to fish consumption by Portuguese preschool children. For this purpose, databases (from IPMA and literature) were mined and mathematically processed by a model based on the Extreme Value Theory assuming consumption scenarios. Eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) and selenium (Se) and methylmercury (MeHg) were selected as critical components of fish, given their health impact and significant contents in some fish species. Assessment also took into account that Se may protect against MeHg toxicity. With exception of blue shark, Se Health Benefit Value (Se-HBV), was always positive (ranging between 3.3 and 14.9) and Se:MeHg ratio was always higher than one (3.8 to 32.3). It was also estimated that the deleterious effects of MeHg on children IQ were offset by the beneficial impact of EPA+DHA in fish except for grilled black scabbardfish consumed every day. Blue shark, regardless of the culinary treatment, yielded very high probabilities of exceeding MeHg TWI (higher than 84 % with a single weekly meal), thus raising serious concerns. EPA+DHA benefits were high in salmon regardless of culinary treatment (> 84 %). Fish consumption by children is advisable with exception of blue shark and boiled and grilled tuna.

Cooking and co-ingested polyphenols reduce in vitro methylmercury bioaccessibility from fish and may alter exposure in humans

Fish consumption is a major pathway for mercury exposure in humans. Current guidelines and risk assessments assume that 100% of methylmercury (MeHg) in fish is absorbed by the human body after ingestion. However, a growing body of literature suggests that this absorption rate may be overestimated. We used an in vitro digestion method to measure MeHg bioaccessibility in commercially-purchased fish, and investigated the effects of dietary practices on MeHg bioaccessibility. Cooking had the greatest effect, decreasing bioaccessibility on average to 12.5±5.6%. Polyphenol-rich beverages also significantly reduced bioaccessibility to 22.7±3.8% and 28.6±13.9%, for green and black tea respectively. We confirmed the suspected role of polyphenols in tea as being a driver of MeHg's reduced bioaccessibility, and found that epicatechin, epigallocatechin gallate, rutin and cafeic acid could individually decrease MeHg bioaccessibility by up to 55%. When both cooking and polyphenol-rich beverage treatments were combined, only 1% of MeHg remained bioaccessible. These results call for in vivo validation, and suggest that dietary practices should be considered when setting consumer guidelines for MeHg. More realistic risk assessments could promote consumption of fish as a source of fatty acids, which can play a protective role against cardiovascular disease.

Consumption of seafood and its estimated heavy metals are associated with lipid profile and oxidative lipid damage on healthy adults from a Spanish Mediterranean area: A cross-sectional study

The association between the consumption of seafood and its benefits on cardiovascular (CVD) risk can be challenged by its heavy metal (HM) content. This study aimed to explore the association of seafood consumption and its estimated HM contents with the lipid profile and lipid oxidation biomarkers in adults from a Spanish Mediterranean area who do not present risk factors for CVD. In this cross-sectional study, the clinical history, three-day dietary record, lipid profile (LDLc, HDLc, APOB/A, and triglyceride levels), plasma oxidised LDL (oxLDL) and 8-isoprostane levels of 81 adults without risk factors for CVD [43% men, with a mean age of 43.6 years (95%CI: 40.1-47.1)] were assessed. The HM [arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb)] contents of seafood were estimated according to data from analyses of marine species in the same Mediterranean area. Moderate adherence to the Mediterranean diet (score: 4.6 of 9) with a mean seafood consumption of 74.9g/day (95%CI: 59.9-89.9), including 22.7g of shellfish per day (95%CI: 13.5-31.9), was observed. The estimated HM contents were lower than the provisional tolerable weekly intakes (PTWIs): 21.12µg/kg/week As, 0.57µg/kg/week InAs, 0.15µg/kg/week Cd, 1.11µg/kg/week Hg and 0.28µg/kg/week Pb. After adjusting by confounder variables, an increase in shellfish consumption was associated with increases in the levels of LDLc (P=0.013), non-HDLc (P=0.015), APOB/A (P=0.02) and plasma oxLDL (P=0.002). Moreover, an increase in the estimated As and Hg levels in shellfish was associated with an increase in LDLc (P=0.015 and P=0.018, respectively), non-HDLc (P<0.008 and P<0.008, respectively), APOB/A ratio (P=0.008 and P=0.009, respectively), and oxLDL (P≤0.001 and P≤0.001, respectively) levels. In conclusion, in adults without risk factors for CVD, increasing shellfish consumption, even by a moderate amount, could favour a pro-atherogenic lipid profile and a higher level of oxidised LDL. These associations are likely influenced by the estimated exposure to As and Hg from shellfish despite these values are lower than the PTWIs.

Content of cadmium and lead in raw, fried and baked commercial frozen fishery products consumed in Poland

BACKGROUND

The study aimed to verify whether the consumption of frozen fishery products was safe in terms of Cd and Pb content. The study material was 31 frozen fishery products (15 breaded products and 16 fillets). Immediately before the analyses the products were subject to culinary treatment according to the recommendations of the producer: fried in colza oil or baked in a gas oven. The level of Cd and Pb was determined using the GF AAS method.

RESULTS

The analysed frozen products contained on average 14.0 µg Cd kg^-1 and 18.5 µg Pb kg^-1 . Compared to raw products, baked fish contained 56% more Cd and 72% more Pb, whereas fried fish contained 16% more Cd and 15% more Pb. Compared to fried products, baked fish contained 34% more Cd and 49% more Pb.

CONCLUSION

The content of Cd and Pb in the products did not exceed the acceptable standard. However, it cannot be clearly stated which method of culinary treatment of frozen fishery products is the best with regard to the level of Cd and Pb in the final products. © 2016 Society of Chemical Industry.

Virgin Olive Oil as Frying Oil

Frying is one of the oldest cooking procedures and is still among the most popular ones for food preparation. Due to their unique sensory characteristics, fried foods are consumed often and with pleasure. During frying, part of the oil is absorbed by the food, thereby becoming part of our diet; most interestingly, in the Mediterranean area approximately 50% of total fat intake is provided by cooking fats. Olive oil is the key lipid component of the Mediterranean diet, the health-promoting effects of which have been largely attributed to olive oil intake. Olive oil is unique among vegetable oils due to its desirable lipid profile and some of its minor components. Scientific evidence now indicates that during frying olive oil behavior is usually equal or superior to that of refined vegetable oils. Herein, an overview of virgin olive oil performance under frying is given, with special reference to the fate of olive oil microconstituents. The compositional changes of foods fried in olive oil are also reviewed and discussed in detail.

Mercury pollution in vegetables, grains and soils from areas surrounding coal-fired power plants

Mercury contamination in food can pose serious health risks to consumers and coal-fired power plants have been identified as the major source of mercury emissions. To assess the current state of mercury pollution in food crops grown near coal-fired power plants, we measured the total mercury concentration in vegetables and grain crops collected from farms located near two coal-fired power plants. We found that 79% of vegetable samples and 67% of grain samples exceeded the PTWI's food safety standards. The mercury concentrations of soil samples were negatively correlated with distances from the studied coal-fired power plants, and the mercury contents in lettuce, amaranth, water spinach, cowpea and rice samples were correlated with the mercury contents in soil samples, respectively. Also, the mercury concentrations in vegetable leaves were much higher than those in roots and the mercury content of vegetable leaves decreased significantly after water rinses. Our calculation suggests that probable weekly intake of mercury for local residents, assuming all of their vegetables and grains are from their own farmland, may exceed the toxicologically tolerable values allowed, and therefore long-term consumptions of these contaminated vegetables and grains may pose serious health risks.

Carcinogenicity of consumption of red meat and processed meat: A review of scientific news since the IARC decision

In October 2015, the International Agency for Research on Cancer (IARC) issued a press release on the results of the evaluation of the carcinogenicity of red and processed meat. Based on the accumulated scientific literature, the consumption of red meat was classified as "probably carcinogenic to humans" and processed meat as "carcinogenic to humans". Given the importance of this topic, this review was aimed at revising the current state-of-the-art on the carcinogenicity of red and processed meat, some time after the IARC decision. Some new epidemiological studies and new reviews clearly supporting the IARC decision have been published during these months. However, a number of gaps still exist. It is basic to establish the mechanisms leading to the increased risk of colorectal cancer (CRC) and other cancers arising from red and processed meat consumption. Another important pending issue is to establish the role of known/suspected carcinogens contained in uncooked or unprocessed meats, as well as the influence of cooking. Finally, it would be highly recommended to conduct new epidemiological studies to elucidate whether the consumption of white meat, such as pork and/or poultry, are -positively or inversely-associated with an increased risk of CRC and other types of cancer.

Differential Tissue Accumulation of Copper, Iron, and Zinc in Bycatch Fish from the Mexican Pacific

In order to ascertain if Cu, Fe, and Zn are differentially accumulated in fish tissues, metal concentrations were measured in the muscle and liver of bycatch fish from the states of Sinaloa (189 specimens, 7 species) and Guerrero (152 individuals, 8 species) in the Mexican Pacific Coast during March and November 2011. Additionally, metal levels were compared with the maximum allowable limits set by international legislation and contrasted with similar ichthyofauna from other regions. Liver had more elevated concentrations of Cu (Sinaloa 28.3, Guerrero 16.3 μg g^-1), Fe (Sinaloa 1098, Guerrero 636 μg g^-1), and Zn (Sinaloa 226, Guerrero 186 μg g^-1) than the muscle in fish from both studied areas. The relative abundances of analyzed metals in both tissues was Fe > Zn > Cu. As far as limits set by international legislation (Australia, India, New Zealand, Zambia), measured concentrations of Cu in the edible portion of fish were not found to be above the set values. In the case of Zn, the maximum allowable limits set by international legislation were exceeded by the Peruvian mojarra Diapterus peruvianus from Guerrero state (Mexican Pacific). No limits exist for Fe in the edible portion of fishery products in the national and international legislations.

A Review of Mercury Bioavailability in Humans and Fish

To estimate human exposure to methylmercury (MeHg), risk assessors often assume 95%–100% bioavailability in their models. However, recent research suggests that assuming all, or most, of the ingested mercury (Hg) is absorbed into systemic circulation may be erroneous. The objective of this paper is to review and discuss the available state of knowledge concerning the assimilation or bioavailability of Hg in fish and humans. In fish, this meant reviewing studies on assimilation efficiency, that is the difference between ingested and excreted Hg over a given period of time. In humans, this meant reviewing studies that mostly investigated bioaccessibility (digestive processes) rather than bioavailability (cumulative digestive + absorptive processes), although studies incorporating absorption for a fuller picture of bioavailability were also included where possible. The outcome of this review shows that in a variety of organisms and experimental models that Hg bioavailability and assimilation is less than 100%. Specifically, 25 studies on fish were reviewed, and assimilation efficiencies ranged from 10% to 100% for MeHg and from 2% to 51% for Hg(II). For humans, 20 studies were reviewed with bioaccessibility estimates ranging from 2% to 100% for MeHg and 0.2% to 94% for Hg(II). The overall absorption estimates ranged from 12% to 79% for MeHg and 49% to 69% for Hg(II), and were consistently less than 100%. For both fish and humans, a number of cases are discussed in which factors (e.g., Hg source, cooking methods, nutrients) are shown to affect Hg bioavailability. The summaries presented here challenge a widely-held assumption in the Hg risk assessment field, and the paper discusses possible ways forward for the field.

Nutrients and Chemical Pollutants in Fish and Shellfish. Balancing Health Benefits and Risks of Regular Fish Consumption

Dietary patterns and lifestyle factors are clearly associated with at least five of the ten leading causes of death, including coronary heart disease, certain types of cancer, stroke, non-insulin insulin-dependent diabetes mellitus, and atherosclerosis. Concerning specifically fish and seafood consumption, its beneficial health effects in humans are clearly supported by an important number of studies performed in the last 30 years. These studies have repeatedly linked fish consumption, especially those species whose contents in omega-3 fatty acids are high, with healthier hearts in the aging population. The nutritional benefits of fish and seafood are also due to the content of high-quality protein, vitamins, as well as other essential nutrients. However, a number of studies, particularly investigations performed in recent years, have shown that the unavoidable presence of environmental contaminants in fish and shellfish can also mean a certain risk for the health of some consumers. While prestigious international associations as the American Heart Association have recommended eating fish at least two times (two servings a week), based on our own experimental results, as well as in results from other laboratories, we cannot be in total agreement with that recommendation. Although a regular consumption of most fish and shellfish species should not mean adverse health effects for the consumers, the specific fish and shellfish species consumed, the frequency of consumption, as well as the meal size, are essential issues for adequately balancing the health benefits and risks of regular fish consumption.

Balancing the benefits and costs of traditional food substitution by indigenous Arctic women of childbearing age: Impacts on persistent organic pollutant, mercury, and nutrient intakes

For indigenous Arctic Canadians, traditional food consumption represents a key source of nutrients and environmental contaminants. Particularly, ingestion of marine mammal blubber and meat may lead to persistent organic pollutant levels and mercury intakes that exceed regulatory thresholds for sensitive populations. We investigated whether temporary adjustments to the consumption of traditional food derived from marine mammals appreciably impacted contaminant exposure and nutrient intakes among indigenous women of childbearing age. Such adjustments can be motivated by the desire to lower contaminant exposure or to increase nutrition, or by the diminishing availability of other traditional food sources. We combined the contaminant fate and transport model GloboPOP with the food chain bioaccumulation model ACC-Human Arctic to simulate polychlorinated biphenyl exposures in female 2007-08 Inuit Health Survey participants. We also calculated daily mercury and nutrient intake rates. Our results suggest that a temporary decrease in marine mammal consumption is largely ineffective at reducing exposure to polychlorinated biphenyls, because of their long elimination half-lives. In contrast, substitution of marine mammals was highly efficient at reducing mercury intake, but also appreciably lowered intakes of iron, manganese, selenium, and ω-3 polyunsaturated fatty acids. The impact of increasing intake of traditional food derived from marine mammals during childbearing age greatly depended on baseline consumption rates; replacement is ill-advised for those who already consume a lot of traditional food due to greater polychlorinated biphenyl and mercury exposures, while replacement was potentially beneficial for those with very limited marine mammal consumption due to increased nutrient intakes. Our calculations primarily suggest that considering baseline traditional food intake rates is critical to devising reproductive dietary adjustment strategies that maximize nutrient intake while minimizing environmental contaminant exposure.

Effect of cooking on total mercury content in Norway lobster and European hake and public health impact

The risk of Hg poisoning by eating seafood is considered real from the several international agencies that recommended, by fish consumption advisories, to pregnant women and young children to avoid or severely limit the consumption of the fish and shellfish with a high-range mercury levels. The analyses of two common species, European hake and Norway lobster, collected from an area of Central Adriatic Sea, reported high mercury levels in crustaceans. For Norway lobster total mercury exceeded, in six out of ten analysed pools, the recommended 0.5mg/kg wet weight European limit. Moreover the increased amount of Hg concentrations in Norway lobster cooked samples suggests the necessity to review current procedures of Hg control in food, considering also consumption habits of consumers. The Hg values found in all European hake samples are below the legal limits and, in this species, the boiling did not modify the concentrations in fish tissues.

Assessment of influences of cooking on cadmium and arsenic bioaccessibility in rice, using an in vitro physiologically-based extraction test

The health risks associated with rice consumption may decrease if consumers use cooking practices which can reduce the bioaccessibility of metal(loid)s. The effects of cooking on the Cd and As bioaccessibility, at three contamination levels of rice, were studied. Results indicated that cooking reduced bioaccessibility of Cd and As in rice. Cooking resulted in a significant increase (p<0.01) of Cd and As concentrations in the residual fraction. Low volume water-cooking of rice to dryness reduced total Cd by about 10% for rices A and B, while medium or high volume water-cooking had no effect on Cd bioaccessibility in all rice types. In contrast, low volume cooking did not remove As, but a significant decrease (p<0.05) was observed when cooking with higher volumes of water. This study provides information for a better understanding of more realistic estimation of metal(loid)s exposure from rice and the possible health risks.

Are Chinese consumers at risk due to exposure to metals in crayfish? A bioaccessibility-adjusted probabilistic risk assessment

Freshwater crayfish, the world's third largest crustacean species, has been reported to accumulate high levels of metals, while the current knowledge of potential risk associated with crayfish consumption lags behind that of finfish. We provide the first estimate of human health risk associated with crayfish (Procambarus clarkii) consumption in China, the world's largest producer and consumer of crayfish. We performed Monte Carlo Simulation on a standard risk model parameterized with local data on metal concentrations, bioaccessibility (φ), crayfish consumption rate, and consumer body mass. Bioaccessibility of metals in crayfish was found to be variable (68-95%) and metal-specific, suggesting a potential influence of metal bioaccessibility on effective metal intake. However, sensitivity analysis suggested risk of metals via crayfish consumption was predominantly explained by consumption rate (explaining >92% of total risk estimate variability), rather than metals concentration, bioaccessibility, or body mass. Mean metal concentrations (As, Cd, Cu, Ni, Pb, Se and Zn) in surveyed crayfish samples from 12 provinces in China conformed to national safety standards. However, risk calculation of φ-modified hazard quotient (HQ) and hazard index (HI) suggested that crayfish metals may pose a health risk for very high rate consumers, with a HI of over 24 for the highest rate consumers. Additionally, the φ-modified increased lifetime risk (ILTR) for carcinogenic effects due to the presence of As was above the acceptable level (10(-5)) for both the median (ILTR=2.5×10(-5)) and 90th percentile (ILTR=1.8×10(-4)), highlighting the relatively high risk of As in crayfish. Our results suggest a need to consider crayfish when assessing human dietary exposure to metals and associated health risks, especially for high crayfish-consuming populations, such as in China, USA and Sweden.

Carcinogenicity of consumption of red and processed meat: What about environmental contaminants?

In October 26, 2015, the International Agency for Research on Cancer (IARC) issued a press release informing of the recent evaluation of the carcinogenicity of red and processed meat consumption. The consumption of red meat and processed meat was classified as "probably carcinogenic to humans", and as "carcinogenic to humans", respectively. The substances responsible of this potential carcinogenicity would be generated during meat processing, such as curing and smoking, or when meat is heated at high temperatures (N-nitroso-compounds, polycyclic aromatic hydrocarbons and heterocyclic aromatic amines). However, in its assessments, the IARC did not make any reference to the role that may pose some carcinogenic environmental pollutants, which are already present in raw or unprocessed meat. The potential role of a number of environmental chemical contaminants (toxic trace elements, polycyclic aromatic hydrocarbons, polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, polybrominated diphenyl ethers, polychlorinated diphenyl ethers, polychlorinated naphthalenes and perfluoroalkyl substances) on the carcinogenicity of consumption of meat and meat products is discussed in this paper. A case-study, Catalonia (Spain), is specifically assessed, while the influence of cooking on the concentrations of environmental pollutants is also reviewed. It is concluded that although certain cooking processes could modify the levels of chemical contaminants in food, the influence of cooking on the pollutant concentrations depends not only on the particular cooking process, but even more on their original contents in each specific food item. As most of these environmental pollutants are organic, cooking procedures that release or remove fat from the meat should tend to reduce the total concentrations of these contaminants in the cooked meat.

Influence of Physiological Gastrointestinal Parameters on the Bioaccessibility of Mercury and Selenium from Swordfish

Swordfish tend to accumulate mercury (Hg), but they are rich in selenium (Se), an element that can counteract the toxic effects of Hg. The aim of the present study was to evaluate the concentrations and bioaccessibility of Hg and Se in cooked swordfish and to identify the digestion parameters (pH, residence time, and enzyme concentrations) that may influence their bioaccessibility. The Hg concentrations ranged between 0.17 and 2.82 mg/kg wet weight (ww) and the bioaccessibility between 14 and 92%. The range for Se concentrations was narrower (0.29-1.17 mg/kg ww), with a bioaccessibility that was generally greater than that of Hg (59-103%). Most of the solubilization took place in the gastric step, where acidic pH and the increase in the pepsin concentration led to greater bioaccessibility, especially for Hg. In the intestinal stage, the most notable effect was the decrease in the bioaccessibility of Hg in the presence of bile salts.

Environmental contaminants of emerging concern in seafood--European database on contaminant levels

Marine pollution gives rise to concern not only about the environment itself but also about the impact on food safety and consequently on public health. European authorities and consumers have therefore become increasingly worried about the transfer of contaminants from the marine environment to seafood. So-called "contaminants of emerging concern" are chemical substances for which no maximum levels have been laid down in EU legislation, or substances for which maximum levels have been provided but which require revision. Adequate information on their presence in seafood is often lacking and thus potential risks cannot be excluded. Assessment of food safety issues related to these contaminants has thus become urgent and imperative. A database (www.ecsafeseafooddbase.eu), containing available information on the levels of contaminants of emerging concern in seafood and providing the most recent data to scientists and regulatory authorities, was developed. The present paper reviews a selection of contaminants of emerging concern in seafood including toxic elements, endocrine disruptors, brominated flame retardants, pharmaceuticals and personal care products, polycyclic aromatic hydrocarbons and derivatives, microplastics and marine toxins. Current status on the knowledge of human exposure, toxicity and legislation are briefly presented and the outcome from scientific publications reporting on the levels of these compounds in seafood is presented and discussed.

Influence of bioaccessibility of total mercury, methyl-mercury and selenium on the risk/benefit associated to the consumption of raw and cooked blue shark (Prionace glauca)

This study aimed to identify the benefit and risk associated with raw and cooked blue shark consumption taking into account the bioaccessibility of Se, Hg and MeHg, by using in vitro digestion method. Selenium, Hg and MeHg levels were higher in cooked samples, particularly in grilled blue shark. Whereas Se bioaccessibility was above 83% in grilled samples, Hg and MeHg bioaccessibility was lower in grilled samples with values near 50%. In addition, all Se-Health Beneficial Values were negative and the molar MeHg:Se ratios were higher than one. The risk-benefit assessment yielded a maximum consumption of one yearly meal for raw or cooked blue shark, thus emphasizing the need to recommend the consumption of a wider variety of seafood species in a balanced and healthy diet.

Integrated risk index for seafood contaminants (IRISC): Pilot study in five European countries

Consumption of seafood is one of the most relevant pathways of exposure to environmental pollutants present in food. The list of toxic compounds in seafood is very extensive, including heavy metals, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). In order to quantify the importance of the problem, tools to combine and simplify large data collections are mandatory for risk managers and decision-makers. In this study, the development of a prioritization setting focusing on chemical hazards taken up through seafood was aimed. For this purpose, the toxicity data of several chemicals was integrated with concentration and seafood consumption data, building an integrated risk index for seafood contaminants (IRISC) able to draw a map of risk for each chemical and family of chemicals. A pilot trial was performed on a sample of 74 pollutants, four seafood species and five European countries (Belgium, Ireland, Italy, Portugal and Spain). The preliminary results revealed that Portugal and Spain presented the highest IRISC, while Belgium was the region with the lowest IRISC. The contribution of each group of contaminants to the IRISC was very similar among countries, with heavy metals being the major contributor, followed by PCBs, PCDD/Fs and endocrine disrupting compounds. When the contribution of different seafood species to the Risk Indexes (RIs) was compared, the results elucidated the high input from sardines, showing the highest rates (54.9-76.1) in the five countries. The IRISC provides a friendly approach to the chemical risk scene in Europe, establishing normalized prioritization criteria considering toxicity and consumption as well as concentration of each chemical.

Human dietary exposure to polycyclic aromatic hydrocarbons: A review of the scientific literature

Polycyclic aromatic hydrocarbons (PAHs) are a group of over 200 different organic compounds that are mainly formed as the result of pyrolytic processes. For the general population, a number of studies have shown that, as for other environmental organic contaminants, the major route of exposure to PAHs is through food consumption. In this paper, the scientific literature concerning the concentrations of PAHs in food and the human dietary intake of these compounds, is reviewed. Unexpectedly, we have detected a considerable lack of scientific papers for countries such as Australia, Canada, Germany, or Japan, among many others, which seems rather unusual given the important scientific and social interest on the knowledge of the health risks of human exposure to environmental pollutants. The data from countries for which the human dietary intake of PAHs is available, show important differences among them, which would be explained by a number of factors, being probably the most important, the different methodologies used in the respective surveys. Regarding the influence of cooking on the levels of PAHs in foodstuffs, and the consequent intake, we conclude that it depends, not only on the particular cooking process, but even more on the specific characteristics of the respective food items.