Mercury,lead, arsenic,and cadmium in Norwegian seafood products and consumer exposure

ABSTRACT

Seafood can be a source of contaminants, which may raise health concerns. The aim of this study was to analyse the levels of inorganic contaminants in commercially available seafood products and assess consumer exposure. Commercially available samples were collected from 2015–2018 and analysed as composite samples for mercury, lead, arsenic, and cadmium, using accredited methods. Levels of cadmium, lead, and arsenic were low and human exposure of these metals would be minimal from consumption of the analysed seafood products. Mercury levels were well below the EU maximum limit for mercury in fish. However, children, who are high consumers, might be at risk of exceeding the tolerable weekly intake for methyl mercury, when eating products with the highest mercury levels. The collected data can be used for future risk-benefit assessments as intake of processed seafood products represent a large proportion of the populations' seafood intake in Europe.     

Rapid identification of grouper and wreck fish meals by ELISA: a field study in restaurants

Grouper (Epinephelus marginatus) and wreck fish (Polyprion americanus) are two costly and demanding fish species which are subjected to substitution in the restaurant industry. In our study, 44 purported grouper and wreck fish meals (24 from school and university lunch rooms and 20 from restaurants) were analysed using an indirect enzyme‐linked immunosorbent assay (ELISA) (microtiter plates and immunostick format) and a MAb specific to these fish species. The results showed that 29 out of 44 meal samples were misdescribed in the restaurant menus. This ELISA procedure, which has proved to be specific, sensitive, cheap and very simple to develop, could be very useful for accurate authentication of meals in the restaurant industry.     

Survey of Salmonella contamination of raw shell eggs used in food service premises in the United Kingdom, 2005 through 2006

This survey was launched after an unusual number of Salmonella Enteritidis outbreaks associated with the use of eggs in food service premises in England and Wales. Between November 2005 and December 2006, 9,528 eggs (1,588 pooled samples of 6 eggs) were collected from 1,567 food service premises in the United Kingdom, most of which (89%) were produced in the United Kingdom. Salmonella was isolated from 6 (0.38%) pools of eggs. Of these, 5 (0.31%) were Salmonella Enteritidis, which were further characterized to phage types (PTs): PT 4 (0.19%), PT 8 (0.06%), and PT 12 (0.06%). Salmonella Mbandaka was also isolated (0.06%). Salmonella was detected from five and one of pooled eggs samples that were produced in the United Kingdom and Germany, respectively; these were from different producers. The study showed evidence of poor egg storage and handling practices in food service premises, in that 55% did not store eggs under refrigerated conditions; 20.7% of eggs had expired "best before" dates or were in use after 3 weeks of lay, indicating poor stock rotation; and 37.1% pooled eggs not intended for immediate service. Eggs are a commonly consumed food that may occasionally be contaminated with Salmonella at different rates, according to their country of origin. The food service sector needs to be aware of this continuing hazard, receive appropriate food safety and hygiene training on storage and usage of raw shell eggs, adopt appropriate control measures, and follow advice provided by national food agencies in order to reduce the risk of infection.     

Quality evaluation of fish and other seafood by traditional and nondestructive instrumental methods: Advantages and limitations

Although being one of the most vulnerable and perishable products, fish and other seafoods provide a wide range of health-promoting compounds. Recently, the growing interest of consumers in food quality and safety issues has contributed to the increasing demand for sensitive and rapid analytical technologies. Several traditional physicochemical, textural, sensory, and electrical methods have been used to evaluate freshness and authentication of fish and other seafood products. Despite the importance of these standard methods, they are expensive and time-consuming, and often susceptible to large sources of variation. Recently, spectroscopic methods and other emerging techniques have shown great potential due to speed of analysis, minimal sample preparation, high repeatability, low cost, and, most of all, the fact that these techniques are noninvasive and nondestructive and, therefore, could be applied to any online monitoring system. This review describes firstly and briefly the basic principles of multivariate data analysis, followed by the most commonly traditional methods used for the determination of the freshness and authenticity of fish and other seafood products. A special focus is put on the use of rapid and nondestructive techniques (spectroscopic techniques and instrumental sensors) to address several issues related to the quality of these products. Moreover, the advantages and limitations of each technique are reviewed and some perspectives are also given.     

Characterization,antigenicity and detection of fish gelatine and isinglass used as processing aids in wines

Fish gelatine (FG) and isinglass (IG) are widely used in the pharmaceutical industry and as ingredients or processing aids in food production. Both products are the focus of interest since several countries, particularly the member states of the EU and Japan, USA, Australia and New Zealand, have introduced special labelling regulations for allergenic foodstuffs, such as fish and products thereof. Thus, there is a demand for a reliable and sensitive method for the detection of FG and IG in foodstuffs. In this study, the characterization of various FGs and IGs, polyclonal antibodies raised against fish collagen and the development of a sensitive indirect ELISA for the detection of FG and IG is described. The ELISA method detected ≤0.11 µg ml^?1 from all FGs and IGs tested. The indirect ELISA was applied to various experimental wines where FG and IG had been used as processing aids and to several commercial wines. No residues of FG and IG were detected in the experimental wines additionally treated with bentonite, a strong adsorbent for proteins, and successive filtration. Additionally, no residues were found in the commercial wines. However, amounts of up to 0.33 µg ml^?1 were found in some experimental wines not treated with bentonite and successive filtration. Therefore, wines may contain traces of FG and IG that were used as processing aids during wine production. However, treatment with bentonite in combination with additional filtration had a clear impact on these residues.     

Human exposure to lead,cadmium and mercury through fish and seafood product consumption in Italy: a pilot evaluation

The presence of selected toxic heavy metals, such as cadmium (Cd), lead (Pb) and mercury (Hg), was investigated in fish and seafood products, namely, blue mussel, carpet shell clam, European squid, veined squid, deep-water rose shrimp, red mullet, European seabass, gilthead seabream, Atlantic cod, European hake, Atlantic bluefin tuna and swordfish so as to assess their human exposure through diet. Metals were detected by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) and hydride generation atomic absorption spectrometry (Hg-AAS). Measurements of Cd, Pb and Hg were performed by means of analytical methods validated in compliance with UNI CEI EN ISO/IEC 17025 [2005. General requirements for the competence of testing and calibration laboratories. Milano (Italy): UNI Ente Nazionale Italiano di Unificazione]. The exposure assessment was undertaken matching the levels of Cd, Pb and total Hg with consumption data related to fish and seafood products selected for this purpose. In order to establish human health implications, the estimated weekly intakes (EWIs) for Cd, Pb and Hg were compared with the standard tolerable weekly intakes (TWI) for Cd and provisional tolerable weekly intakes (PTWIs) for Pb and Hg stipulated by the European Food Safety Authority (EFSA) and the Food and Agriculture Organization/World Health Organization (FAO/WHO) Joint Expert Committee on Food Additives (JECFA). The found metal concentrations were largely below the maximum levels (MLs) established at the European Union level with the exception of Cd. This metal exceeded the MLs in squid, red mullet, European hake and Atlantic cod. Squid and blue mussel showed the highest Pb concentrations which accounted for 60% and 10% of the MLs, respectively. Highest Hg levels were found in predatory fish. The concentrations of Hg in swordfish, Atlantic bluefin tuna and red mullet accounted for 50%, 30% and 30% of the MLs, respectively. The EWIs for Cd, Pb and Hg related to the consumption of fish and seafood products by the median of the Italian total population accounted for 20%, 1.5% and 10% of the standard TWI for Cd as well as PTWIs for Pb and Hg, respectively. Furthermore, the EWIs estimated using consumption data concerning Italian consumers did not exceed the standard TWI and PTWIs, except for Cd at 95th percentile.     

Gluten contamination of naturally gluten-free flours and starches used by Canadians with celiac disease

A large national investigation into the extent of gluten cross-contamination of naturally gluten-free ingredients (flours and starches) sold in Canada was performed. Samples (n = 640) were purchased from eight Canadian cities and via the internet during the period 2010–2012 and analysed for gluten contamination. The results showed that 61 of the 640 (9.5%) samples were contaminated above the Codex-recommended maximum level for gluten-free products (20 mg kg^–1) with a range of 5–7995 mg kg^–1. For the ingredients that were labelled gluten-free the contamination range (5–141 mg kg^–1) and number of samples were lower (3 of 268). This picture was consistent over time, with approximately the same percentage of samples above 20 mg kg^–1 in both the initial set and the subsequent lot. Looking at the total mean (composite) contamination for specific ingredients the largest and most consistent contaminations come from higher fibre ingredients such as soy (902 mg kg^–1), millet (272 mg kg^–1) and buckwheat (153 mg kg^–1). Of the naturally gluten-free flours and starches tested that do not contain a gluten-free label, the higher fibre ingredients would constitute the greatest probability of being contaminated with gluten above 20 mg kg^–1.     

Fast analysis of glufosinate,glyphosate and its main metabolite,aminomethylphosphonic acid,in edible oils,by liquid chromatographycoupled with electrospray tandem mass spectrometry

ABSTRACT

A method has been developed for the rapid, specific, accurate, precise and sensitive determination of glufosinate, glyphosate and its major metabolite, aminomethylphosphonic acid, in edible oils, by liquid chromatography coupled to tandem mass spectrometry. Oils were extracted with acidified water (1% formic acid), and the extracts were directly injected into an LC using a Hypercarb column as the stationary phase. The analytes were eluted by a mobile phase of methanol and water containing 1% acetic acid, and they were ionised by electrospray ionisation in negative ion mode. The method was validated and limits of quantification ranged from 5 μg kg^?1 (aminomethylphosphonic acid) to 10 μg kg^?1 (glyphosate and glufosinate). Three concentrations (10, 50 and 100 μg kg^?1) were selected to perform recovery studies. Mean recoveries ranged from 81.4% to 119.4%. Intra and inter-day precision were lower than 19%. Different edible oils were analysed, and no residues of the studied herbicides were detected above limits of quantification.     

Wheat preharvest herbicide application,whole‐grain flour properties,yeast activity and the degradation of glyphosate in bread

The aim of this study was to determine the effects of wheat preharvest application of a glyphosate‐based herbicide (Roundup WeatherMax^® with Transorb^® 2 Technology) on whole‐grain flour composition and properties, including yeast activity. The effect of dough fermentation on the degradation of herbicide residues was also estimated. Grain samples from two hard red spring wheat varieties exceeded the maximum residue limits (5 mg kg^?1) in Canada. Glyphosate had minor effects on wheat kernels composition and properties, including fructans content and yeast gassing power. No degradation of Roundup^® or pure glyphosate was seen after dough fermentation for up to 4 h and baking. These results call for more scientific studies on glyphosate residues in wheat.     

Stability of arsenic compounds in seafood samples during processing and storage by freezing

In this study, the stability of arsenic compounds in fresh and frozen samples of raw, boiled and fried Atlantic cod (Gadhus morhua), Atlantic salmon (Salmo salar) and blue mussel (Mytilus edulis) were examined. Results show that the total arsenic concentrations of the fresh Atlantic cod and Atlantic salmon samples were not different from the frozen samples within the same seafood type. For blue mussel, the total arsenic concentration decreased significantly after storage. Inorganic arsenic was found only in blue mussels and, importantly, no significant increase of inorganic arsenic was observed after processing or after storage by freezing. The content of tetramethylarsonium ion was generally low in all samples types, but increased significantly in all fried samples of both fresh and frozen seafood. Upon storage by freezing, the arsenobetaine content was reduced significantly, but only in the samples of blue mussels.     

速冻米面食品膨松剂的研究

研究一种不含明矾、磷酸盐、酒石酸氢钾、硫酸钙等成分的新型米面食品膨松剂,采用:内酯、柠檬酸、酒石酸、碳酸氢钠等成分,开发出一种可适用于所有食品(包括速冻米面食品)的膨松剂,效果优于传统配方膨松剂.     

Survey of Salmonella contamination of non-United Kingdom-produced raw shell eggs on retail sale in the northwest of England and London, 2005 to 2006

This survey was prompted by a change in the epidemiology of Salmonella Enteritidis infections in England and Wales and elsewhere in Europe and, to our knowledge, is the first survey to provide information on Salmonella contamination of non-United Kingdom eggs on retail sale. Based on 10,464 non-United Kingdom eggs (1744 pooled samples of six eggs) purchased between March 2005 and July 2006, the total weighted prevalence estimate for all Salmonella detected in non-United Kingdom eggs was 3.3%. Of the eggs sampled, most were produced in Spain (66.3%), France (20.0%), or The Netherlands (7.4%). Salmonella was detected from 4.4 and 0.3% of eggs produced in Spain and France, respectively, with weighted prevalence estimates. Eight different Salmonella serotypes were recovered from non-United Kingdom eggs, of which Salmonella Enteritidis predominated, with an estimated prevalence of 2.6%. Salmonella Enteritidis was obtained only from Spanish eggs. Nine different phage types of Salmonella Enteritidis were identified, with phage type 1 found to be the predominant phage type. Most of the Salmonella Enteritidis isolates obtained from Spanish eggs in the survey were resistant to nalidixic acid with concomitant decreased susceptibility to ciprofloxacin (0.125 to 1.0 mg/liter) or ampicillin (8.0 mg/liter). Salmonella Enteritidis phage type 1 until now had not been detected in eggs examined as part of previous United Kingdom egg surveys but has been detected in eggs of Spanish origin examined during recent national outbreaks of Salmonella Enteritidis non-phage type 4 infections in England and Wales. Eggs are a commonly consumed food that may occasionally be contaminated with Salmonella. The rates of contamination may be linked to the origin of the eggs. Consumers and caterers need to be aware of this continuing hazard, adopt appropriate control measures, and follow advice provided by national food agencies in order to reduce the risk of infection.     

Changes in iron,zinc and chelating agents during traditional African processing of maize: Effect of iron contamination on bioaccessibility

The effect of the different unit operations of processing traditionally used to produce four maize foods commonly consumed in Africa on the nutritional composition of the products was investigated, using Benin as a study context. The impact of the processes on lipid, fibre, phytate, iron and zinc contents varied with the process. The lowest IP₆/Fe and IP₆/Zn molar ratios, the indices used to assess Fe and Zn bioavailability were obtained in mawè, a fermented dough. Analysis of maize products highlighted a significant increase in iron content after milling, as a result of contamination by the equipment used. Evaluation of iron bioaccessibility by in vitro enzymatic digestion followed by dialysis revealed that the iron contamination, followed by lactic acid fermentation, led to a considerable increase in bioaccessible iron content. Extrinsic iron supplied to food products by the milling equipment could play a role in iron intake in developing countries.     

Mercury contamination in commercial fresh and salt water fish of the Zabol Chahnimeh reservoirs and the Gulf of Oman (Iran)

In order to investigate bioaccumulation of mercury in Iranian coastal waters fish, tiger tooth croaker (Otolithes ruber) and yellowspotted trevally (Carangoides fulvoguttatus) from the Gulf of Oman and grass carp (Ctenopharyngodon idella) and silver carp (Hypophthalmichthys molitrix) from Zabol Chahnimeh reservoirs were sampled in May 2012. In these ecosystems, total mercury concentrations were measured in muscle and gill of these four fish species. Both regions did not reveal a significant difference. In H. molitrix and O. ruber, mercury concentrations in gill increased with increasing length (H. molitrix, r = 0.94, p < 0.005; O. ruber, r = 0.94, p > 0.005) and weight (H. molitrix, r = 0.94, p < 0.005; O. ruber, r = 0.82, p > 0.04). Generally, mercury levels in the analysed fish samples were higher than WHO, FDA and US-EPA legal limits.     

Di(2-ethylhexyl) phthalate contamination of retail packed lunches caused by PVC gloves used in the preparation of foods

Plasticizer contamination of foods sold in retail packed lunches and set lunches in restaurants was determined by GC/MS. The phthalate esters were as follows: diethyl, dipropyl, dibutyl, dipentyl, dihexyl, butylbenzyl, dicyclohexyl, di(2-ethylhexyl), dioctyl, diisooctyl (mixture of isomers) and diisononyl (mixture). Di(2- ethylhexyl) adipate was also determined. Sixteen packed lunches and ten set lunches were analysed, and in all samples the concentration of di(2-ethylhexyl) phthalate (DEHP) was the highest, at 0.80-11.8 mg/ kg in packed lunches and 0.012-0.30 mg/kg in set lunches. The DEHP content of five packed lunches exceeded 1.85 mg, which is the EU tolerable daily intake (TDI) for a person of 50 kg body weight. Foodstuffs that were components of the packed lunches were taken from the factory at each step of preparation and phthalates were determined. For example, chicken contained 0.08 mg/kg DEHP when uncooked, 13.1 mg/ kg after frying and 16.9 mg/kg after packing. Disposable PVC gloves used in the preparation of foods were apparently the source of high DEHP concentrations. The gloves used during cooking or packaging were sprayed with 68% (w/w) ethanol to sterilize them. PVC gloves from the factory contained 22 or 41% by weight of DEHP. To confirm the link with the contamination problem, samples of boiled rice, croquette and boiled dry radish were handled in the laboratory with PVC gloves containing 30% (w/w) DEHP. DEHP migration levels of 0.05 mg/kg in rice or 0.33 mg/kg in croquette, and 11.1 mg/kg in radish were found. The alcohol sprayed onto the gloves increased the migration of DEHP to 2.03 mg/kg in rice, 2.45 mg/ kg in croquette, and 18.4 mg/kg in radish.     

原子吸收光谱法测定虾、蟹壳中Pb、Cd、Cr的研究

虾、蟹壳是制备壳聚糖和钙添加剂的重要原料,本文研究了石墨炉原子吸收光谱法测定虾、蟹壳中铅、镉、铬含量的方法,包括检出限、精密度、加标回收率等方法学的研究。实验结果表明：本方法的相对标准偏差为0．79％～4．33％,回收率为90．9％～105．9％,检出限分别为0．3786ng／mL、0．4422ng／mL、0．1448ng／mL。采用本方法测定虾、蟹壳中的铅、镉、铬含量具有灵敏度高、检出限低,操作简便、快速、可靠,具有较好的精密度和准确度。     

靛酚蓝分光光度法对鱼肉与鱼鳞中蛋白质含量的比较测定

采用靛酚蓝分光光度法对两种鱼的鱼肉和鱼鳞中的蛋白质含量进行了比较测定。结果表明该法稳定性、重复性好。该法最大吸收波长为648nm,摩尔吸光系数E648=1．209L·mg^-1·cm^-1,标准曲线相关系数为r=0．9956。溶液经2h后可完全显色,2h后直至24h吸光度无显著变化,平均回收率为98．9％。     

New tools to assess toxicity, bioaccessibility and uptake of chemical contaminants in meat and seafood

Meat and seafood chemical contaminants can be very dangerous for human health. The way in which food chemical contaminants are currently controlled is not optimal as the food cooking, processing and eating habits are generally not considered by authorities. The current review discusses the available information related to the toxicity of the most relevant meat and seafood chemical contaminants, their bioaccessibility after cooking or processing, and the implications for human health. In addition, the current in vivo toxicity and alternative tests carried out for testing the effects of food chemical contaminants are illustrated, as well as new detection tools. The use of non-carcinogenic functional cell models, of alternative animal models like zebrafish embryos, and a toxicogenomic approach seem to be the most promising strategy for the toxicity assessment of food chemical contaminants.     

Thermal Gelation of Pork, Beef, Fish, Chicken and Turkey Muscles as Affected by Heating Rate and pH

Effects of heating rate (3°C or 0.7°C/min) and pH (5.5, 6.0, 6.5, or 7.0) on thermal gelation properties of different muscle systems were evaluated (10% protein, 2% NaCl) using pork, beef, fish, and chicken and turkey (breast and thigh) muscles. Results indicated that, at pH 6.5 and 7.0, force required to rupture the gel (Pf), force required to move plunger through the gel (Fp), and viscosity index (Ni), using a slow heating rate, were higher than with rapid heating. All muscles (except breast muscles with the slow heating rate) yielded higher (P<0.05) gel strength (Fp, Pf) at pH 6.0 than at the other pHs.     

Absorption of benzoic and sorbic acids by herring and prawns in marinades

The preservatives benzoic acid and sorbic acid are rapidly removed from marinades in which they are incorporated to the flesh of herring and prawn. Allowing for the water content of each species and the fish/marinade ratio, concentrations of both acids in the fish are markedly in excess of that predicted from a simple equilibrium.