浙江沿海海产品甲基汞污染调查及膳食风险评估

运用高效液相色谱-原子荧光联用法研究海产品肌肉中汞形态分布特征,调查了浙江沿海50 个品种共计891 个样本中甲基汞含量,并结合浙江省居民水产品消费量,对海产品甲基汞污染食用风险进行了评估。结果显示：94.2%的海产品均有甲基汞检出,甲基汞是海产品肌肉中汞元素的主要存在形态,其含量占总汞质量分数65.0%～95.2%,所有样品甲基汞含量范围为0～0.95 mg/kg,均低于国家标准限量值;不同鱼类甲基汞含量存在差异,营养级别高的鱼类对甲基汞的生物富集能力较强,鲨鱼、金枪鱼等大型肉食性鱼类甲基汞含量明显高于一般鱼类,存在超标可能性;风险评估表明,浙江沿海一般海产品甲基汞污染食用风险较低,但长期或大量食用金枪鱼和鲨鱼等甲基汞污染较高的海产品,存在健康风险。     

甲苯萃取-原子荧光光谱法检测鱼肉中甲基汞

目的建立甲苯萃取-原子荧光光谱检测鱼肉中甲基汞的方法。方法样品经48%氢溴酸水解、甲苯萃取、0.05 mol/L硫代硫酸钠反萃取后,应用AFS-9230原子荧光光谱法进行测定,同时经此前处理后的样品采用DMA-80直接测汞仪进行测定,与原子荧光光谱法的结果进行对比。结果原子荧光光谱法以及直接测汞仪直接测定的结果与标准物质定值吻合,确证该方法的可靠性,适用于鱼、贝等水产品中甲基汞的测定。采用该方法对鱼肉中总汞与甲基汞成分分析标准物质GBW10029以及英国食品分析水平评估计划(food analysis performance assessment scheme,FAPAS)的罐装鱼肉样品(样品编号07189)进行了检测,检测结果与参考物定值吻合,回收率分别为96.1%,97.5%。结论该方法操作简单,灵敏度高,重现性好,适用于鱼肉中甲基汞含量的定量检测。     

酸提取巯基棉-氢化物发生原子荧光法测定海产品中的甲基汞

对国标方法 GB/T 5009.17-2003进行优化和改进,建立酸提取巯基棉-氢化物发生原子荧光法(hy-dride generation-atomic fluorescence spectrometry,HG-AFS)测定海产品中甲基汞的方法。样品研磨均匀后,加入含有Cu2+的盐酸萃取样品中的甲基汞,经离心、过滤后用巯基棉吸附,洗脱后用原子荧光仪检测,外标法定量。结果表明:甲基汞在0～8.0μg/L内,荧光强度与甲基汞质量浓度之间线性关系良好(相关系数为1),以2.0、5.0μg/L 2个添加量在样品中添加甲基汞,平均回收率在97.0%～116.5%,相对标准偏差为1.5%～3.0%,方法的检出限为0.1 mg/kg。该方法简便快速,机体干扰小,检出限低,精密度、准确性均能满足海产品中甲基汞的测定要求。     

气相色谱法测定肉制品中甲基汞

研究肉制品中甲基汞检测方法.利用盐酸超声浸提样品后,将样品提取液用氯化钠盐析-苯萃取的方法,提取出各类食品中的甲基汞,建立了气相色谱法(附电子捕获检测器)测定食品中甲基汞的方法.本方法相对标准偏差1.31％～3.99％,检出限为0.01 mg/kg,回收率在86.4％～98.9％之间,具有操作简便快速、灵敏度高等优点.     

超声辅助提取—HPLC—ICP—MS同时测定水产及其制品中3种形态汞的含量

建立了采用超声辅助提取,高效液相色谱-电感耦合等离子体质谱联用技术测定水产及其制品中汞形态分析的方法。在盐酸+L-半胱氨酸体系下,对样品进行超声辅助萃取,以10mmol/L乙酸铵+0.10%L-半胱氨酸缓冲盐与甲醇(体积比982)组成流动相,用高效液相色谱-电感耦合等离子体质谱仪同时检测无机汞、甲基汞和乙基汞的含量。无机汞、甲基汞和乙基汞的检出限(3S/N)分别为0.18,0.09,0.15ng/mL,标准曲线回归方程相关系数(R)均0.999。以实际样品对无机汞、甲基汞、乙基汞进行加标回收试验,回收率在78.5%~96.8%,相对标准偏差(RSD)≤3.0%。经对标准物质进行检测,测得值与标准值吻合。该方法准确可靠、简单快速、精密度及准确度结果理想,可用于实际水产及其制品中汞形态的分析。     

高效液相色谱原子荧光分光光度联用法测定海产品中的甲基汞含量

目的 建立高效液相色谱原子荧光分光光度法在线联用技术测定海产品中甲基汞的方法.方法 以25％氢氧化钾甲醇溶液水浴加热后超声提取样品,试液中的甲基汞与2-巯基乙醇结合.以5％甲醇溶液(含60 mmol/L乙酸铵和0.1％2-巯基乙醇)作流动相,经Supelco C18色谱柱(150 mm×4.6 mm,5μm)分离,紫外消解后经KBH4还原由原子荧光光度计进行测定.结果 甲基汞的检出限为0.7 μg/L(以汞计),样品测定的相对标准偏差小于4.6％,采用两种参考物质考查方法的准确性,以测定市售海产品中甲基汞含量.结论 本研究通过简化仪器装置,改进前处理步骤,有效地提高了方法的可靠性,该方法简便、快速、可靠,可用于海产品中甲基汞的含量测定.     

海产品中甲基汞含量的测定与比较

液相色谱-原子荧光联用法,是近年来新兴的一种检测方法。该方法在甲基汞的测定方面,已经具有较广泛的应用。使用上述方法,测定不同海产品中甲基汞的含量。比较检测结果发现,甲基汞在海产品中的含量存在以下特点:样品中甲基汞含量均符合《食品安全国家标准食品中污染物限量》(GB2762-2017)相关要求;鲜品明显低于干品;可食用肉质部分明显低于内脏及头部。因此,建议优先食用新鲜海产品,在食用贝类时,应去除头部及内脏,以降低生物富集作用对健康的影响。     

含鱼辅食制品中总汞和甲基汞含量的测定方法

对常用的汞和甲基汞的测定方法进行了介绍。使用测汞仪直接进样(DMA)和微波消解-原子荧光光谱分析法(AFS)对多种含鱼婴幼儿辅食中总汞进行测定,考察了标准曲线线性及方法检出限,并对测定的结果进行分析,发现2种检测方法下实际样品的测定结果相互吻合,对标准物质(GBW 08571)贻贝的测定结果良好;使用高效液相电感耦合等离子体质谱联用的方法 (HPLC-ICP-MS)测定实际样品中甲基汞含量,方法检出限达到0.0014 mg/kg,并进行加标回收实验,回收率在90%~106%之间,方法灵敏度高,涉及试剂较为安全,过滤提取可以进行批处理,单个样品测定时间在5 min以内。通过多批次样品的测定,发现在多原料的含鱼婴幼儿辅食中,汞含量较低,甲基汞含量均小于检出限,只有在以鱼作为单一原料或是主要原料的辅食产品中,汞含量较高,甲基汞含量随产品中原料鱼性质不同含量比例不同,其中深海鱼(金枪鱼、旗鱼)鱼酥的含量略高,约占总汞比例的30%~60%。     

浙江沿海海产品中汞形态分析测定与分布特征

建立水产品中汞形态分析的盐酸溶液提取、高效液相色谱-原子荧光光谱联用仪测定方法,从提取剂盐酸溶液浓度、络合剂选择、泵速和气体流速方面进行条件优化,方法学评价结果表明该方法准确度高、精密性好;采自浙江沿海的160 个实际样品测定数据证明大部分水产品肌肉中都有甲基汞检出,甲基汞是水产品肌肉中存在的主要形态,其质量分数占总汞质量分数的65.0%～95.2%,食物链级别较高的食肉鱼类甲基汞含量高于普通鱼类;海产品中鱼皮和内脏的总汞含量值高于其鳃和肌肉部位的总汞含量值,且在内脏、鳃和鱼皮中主要是以无机汞形态存在。     

测汞仪/高效液相色谱-电感耦合等离子体质谱联 用法测定鱼松中总汞和甲基汞的含量

目的测汞仪和高效液相色谱-电感耦合等离子体质谱法(high performance liquid chromatography-inductively coupled plasma mass spectrometry,HPLC-ICP-MS)测定鱼松中总汞及甲基汞的含量。方法样品粉碎均匀后,无需前处理环节,直接通过测汞仪内置的模块对样品中的总汞进行一站式检测。以L-半胱氨酸-乙酸铵-甲醇-盐酸为提取液,高效液相色谱分离,ICP-MS为检测手段对样品中的甲基汞进行测定。结果在优化的检测条件下,总汞的检出限为0.05μg/kg,甲基汞的检出限为0.001 mg/kg;5种鱼松样品中总汞的加标回收率为80.2%~109.6%,甲基汞的回收率为85.0%~108.5%,样品中总汞和甲基汞的相对标准偏差均小于8.0%。样品中甲基汞在总汞中的含量约为49.3%~82.5%,是汞的主要存在形态。结论该方法操作简便、提取效率高,可实现鱼松样品中总汞和甲基汞的快速测定。     

Taurine content of raw and processed fish fillets/portions

The health benefits of seafood are well recognised and fish and fish products are increasingly being advocated as functional foods. Taurine is also well recognised as beneficial to cardiovascular health, and seafood is a good source of this compound. This study investigated the taurine content of different fish species and also the use of vacuum tumbling and injection procedures for introducing additional taurine into fish. The taurine content of fish purchased in supermarkets was in the order plaice (146), cod (108), mackerel (78) and farmed salmon (60 mg/100 g fresh weight). Spot-sample tests on 14 other fish species showed a wide range (6–176 mg/100 g fresh weight) in taurine contents. Vacuum tumbling and injection in/with a taurine/sodium tripolyphosphate solution were used successfully to enrich tuna cubes (800 mg/100 g fresh weight) and salmon sides (891 mg/100 g fresh weight), respectively, with taurine thus making them (potentially) functional foods. The added taurine was well retained in processed tuna cubes and did not adversely affect the sensory acceptability of the samples. Taurine retention in cooked taurine-enriched tuna cubes was best for grilling followed by microwave heating and steaming.     

Simultaneous Estimation and Modeling of Thermophysical Properties of Big-Eyed Tuna and Pacific Cod

The thermophysical properties (thermal conductivity, thermal diffusivity, and specific heat) of big-eyed tuna and pacific cod were measured at various temperatures (5–50°C) by the modified version of current probe method. The optimal prediction models for these thermophysical properties were determined. The random model was applied to predict the thermal conductivity of seafood in a wide range of temperature and it provided the accurate predictions for the samples. The thermal diffusivities of the samples could be predicted by Martens’s equation. An additive relationship exists between the specific heat of the sample, the composition, and the specific heat of each component.     

Incidence of Listeria monocytogenes in raw seafood products in Japanese retail stores

The incidence of Listeria monocytogenes in raw fish, shellfish, and fish roe was investigated in seafood products collected from randomly selected retail stores in and around Tokyo, Japan. Of the 10 samples of 208 examined found positive for L. monocytogenes by mini-VIDAS LMO, seven were fish roe (cod, salmon) and three were minced tuna. Three serotypes (1/2a, 1/2b, 3b) were detected among the isolated strains; serotype 1/2a was predominant (8 of 10).     

Comparison of Two Analytical Methods for the Analysis of Methylmercury in Fish

In this study, we compared a high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS) method and an isotope dilution gas chromatography mass spectrometry (ID-GC-MS) method for the analysis of methylmercury (MeHg) in fish samples. Using HPLC-ICP-MS, the limit of detection (LOD) was 2.0 ngHg?·?g^?1 for inorganic Hg and was 5.0 ngHg?·?g^?1 for MeHg. In comparison, the LOD for MeHg was 3.4 ngHg?·?g^?1 for using ID-GC-MS. Certified reference material (CRM) results agreed well with certified values for both methods. The mean recovery for analysis of CRM BCR 463 by HPLC-ICP-MS was 99?±?2.1 % for MeHg and was 103?±?2.1 % for total Hg. Two CRMs, BCR 463 and CRM DORM2, were analyzed by ID-GC-MS, the mean recovery of MeHg was 87?±?1.9 % for BCR 463, and the mean recovery of MeHg was 102?±?2.9 % for CRM DORM2. Matrix samples spiked with Hg or MeHg at various concentrations were analyzed by two methods. For HPLC-ICP-MS method, the mean recovery for MeHg spiked samples was 93?±?4.2 %. For ID-GC-MS method, the mean recovery for MeHg spiked samples was 91?±?5.2 %. A total of 19 predatory fish and 54 tuna fish samples were analyzed using both methods. No significant difference was observed between the MeHg data generated from both methods. The average relative standard deviation (RSD) between the two datasets for 19 predatory fish samples was 8.8 %. The average RSD between two datasets for 54 tuna fish samples was 4.4 %.The HPLC-ICP-MS method offers substantial advantages over the method of ID-GC-MS because the former method can determine the total mercury (Hg) and MeHg in a single chromatographic run and the analysis time is much shorter. The latter method is time consuming due to overnight digestion and having to conduct presample analysis for signal-matched isotope dilution spiking and requires more expensive isotope labeled reagents.     

Quantitative risk–benefit analysis of fish consumption for women of child-bearing age in Hong Kong

Maternal fish consumption is associated with both risks from methylmercury (MeHg) and beneficial effects from omega-3 fatty acids to the developing foetal brain. This paper assessed the dietary exposure to MeHg of women of child-bearing age (20–49 years) in Hong Kong, and conducted risk–benefit analysis in terms of the effects in children’s intelligent quotient (IQ) based on local data and the quantitative method derived by the expert consultation of FAO/WHO. Results showed that average and high consumers consume 450 and 1500 g of fish (including seafood) per week, respectively. About 11% of women of child-bearing age had a dietary exposure to MeHg exceeding the PTWI of 1.6 µg kg^–1 bw. In pregnant women MeHg intake may pose health risks to the developing foetuses. For average consumers, eating any of the 19 types of the most commonly consumed fish and seafood during pregnancy would result in 0.79–5.7 IQ points gain by their children. For high consumers, if they only ate tuna during pregnancy, it would cause 2.3 IQ points reduction in their children. The results indicated that for pregnant women the benefit outweighed the risk associated with eating fish if they consume different varieties of fish in moderation.     

固相微萃取-气质联用分析方法评价 水产品鲜度研究进展

鲜度是影响水产品品质的重要因素。鲜度评价对水产品加工、储运及安全都具有重要意义。固相微萃取-气质联用方法是一种快速方便检测食品挥发性物质的方法。此方法已经被应用于一些水产品如鳕鱼、鲅鱼、金枪鱼、鲈鱼等挥发性物质检测及鲜度评价中。该方法具有客观、快速、方便的特点。本文就目前该分析方法在水产品鲜度评价中的原理、应用及前景作一简要综述。     

COMPARISON OF THREE METHODS OF FORMALDEHYDE DETERMINATION ON FROZEN SOLE, POLLOCK, HADDOCK AND COD FILLETS

The Merchoquant test strip and a rapid, enzymatic method were evaluated for the quantitation of formaldehyde (HCHO) in neutralized perchloric acid (HC10₄) extracts of fish muscle. Compared with the standard colorimetric Cochin and Axelrod (1959) modification of the Nash reagent method (1953), the nonglutathione dependent formaldehyde dehydrogenase (EC 1.2.1.46) method based on that of Yasuhara et al. (1982) for creatine was faster and less affected by interferences. The enzyme method resulted in lower HCHO values than did the modified Nash method for the gadoid pollock, haddock and cod samples while the semi-quantitative Merchoquant test strip resulted in positive readings for only one cod sample. Seventy-nine HC10₄fish extracts analyzed by the enzyme and modified Nash procedures showed a species dependent correlation between the two methods, with slopes of 0.847, 0.321, 0.436, 0.519 for sole, pollock, haddock and cod, respectively. The HCHO content of the samples ranged between 0.4 and 75 μmoles%. Standard addition evaluation of the accuracy of the formaldehyde dehydrogenase method compared with the modified Nash procedure on three samples also resulted in species dependent slopes. Nongadoid sole samples showed the greatest deviation while cod was the only species where the modified Nash method resulted in HCHO values lower than those attained with the enzyme method. The detection limit of the formaídehyde dehydrogenase method was 0.3 μmoles%.     

Glass Transition Values of Muscle Tissue

Reports of glass transition (Tg') values for frozen muscle tissue are not common and reported values are mostly much lower than would be expected. Tg’ values for muscle tissue and isolated proteins were studied using differential scanning calorimetry. Apparent Tg's of mackerel, cod and beef were similar (ca ?11 to ?13°C) and substantially higher than most published values (?15 to ?77°C for tuna and beef), but in accord with expectations for substances of high molecular weight. Dialyzed insoluble and soluble protein fractions from mackerel yielded apparent Tg’ values (ca ?7°C) that were similar, with both being higher than those for whole muscle. Apparent Tg’ values of ca ?7°C were determined for aqueous samples of gelatin and collagen, but none was detected for zein.     

三亚市红沙海域海产品铅含量分析及评价

代表性采集红沙海域海产品,样品经硝酸湿法消解,原子吸收法测定海产品中总铅含量,根据无公害食品水产品有毒有害物质标准限量对海产品的食用安全性进行评估。采集的样本中,软体动物(墨鱼)铅含量最高,其次是甲壳类(虾、蟹),鱼类铅含量最低。鱼头铅含量最高,其次鱼尾,鱼肉铅含量最低。三亚红沙海域鱼类总体卫生质量较好,鱼肉全部符合农业部评价标准,游客食用鱼肉相对安全。贝类中铅含量高于鱼类,存在铅含量超标现象。