Marine organisms contain arsenic at various concentrations, and so human consumption of seafood products results in arsenic intake. Therefore, identification and quantification of all arsenic compounds present in seafood products are important from the viewpoint of food hygiene, because the toxicity of arsenic strongly depends on its chemical form. Hence, determination of total arsenic concentration and speciation analysis of arsenic compounds in seafood products have been extensively performed. This review covers the large number of arsenic compounds identified in seafood products, and summarizes recent findings on their biological effects and metabolism in humans and experimental animals.

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A novel multiplex PCR method was developed for simultaneous event-specific detection of four events of GM maize, i.e., DAS-59122-7, MIR604, MON88017, and MON863. The single laboratory examination of analytical performance using simulated DNA mixtures containing GM DNA at various concentrations in non-GM DNA suggested that the limits of detection (LOD) of the multiplex PCR method were 0.16% for MON863, MIR604, and MON88017, and 0.078% for DAS-59122-7. We previously developed a nonaplex (9plex) PCR method for eight events of GM maize, i.e., Bt11, Bt176, GA21, MON810, MON863, NK603, T25, and TC1507. Together with the nonaplex PCR method, the newly developed method enabled the detection and identification of eleven GM maize events that are frequently included in commercial GM seed used in Japan. In addition, this combinational analysis may be useful for the identification of combined event products of GM maize.

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We examined the combined estrogenic activity of soybean extract used in a dietary supplement and ethinyl estradiol (EE) contained in an oral contraceptive. Olive oil (control), soybean extract (0.0036 or 0.36 g/kg corresponding to doses of total isoflavone of 0.83 or 83 mg/kg respectively), EE (1 or 10 μg/kg), and soybean extract+EE were administered to ovariectomized CD-1 mice by oral gavage for 4 consecutive days. Soybean extract (0.0036 or 0.36 g/kg) and EE (1 μg/kg) did not increase the relative uterine weight. The relative uterine weight of the soybean extract (0.0036 or 0.36 g/kg)+EE (10 μg/kg) group was significantly higher than that of the control. The relative uterine weight of the soybean extract (0.36 g/kg)+EE (10 μg/kg) group was also significantly higher than that of the EE (10 μg/kg) group. Soybean extract showed estrogenic activity for human estrogen receptor (hER)-α and -β. Coadministration of EE with soybean extract increased the estrogenic activity for hER-α and -β.

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A rapid and sensitive TaqMan real-time PCR assay for the detection of Pacific cod (Gadus macrocephalus) and capelin (Mallotus villosus) roes in Alaska pollack (Theragra chalcogramma) roe product was developed. The primers and the TaqMan MGB (minor groove binder) probes were designed based on the gene encoding cytochrome b for the specific detection of Alaska pollack, Pacific cod and capelin. This real-time PCR assay had the detection limit of 0.002 ng/μL mitochondrial DNA and showed no cross-reaction with 48 other species. The calculated r² values of the standard curves for the three species were 1.000. This assay was applied for the detection of Pacific cod and capelin roes in mixture samples: Pacific cod or capelin roes were added to Alaska pollack roes at 0.1, 1 and 10%. The threshold cycle values were obtained from both of the mixture samples at 0.1%. Practical applicability of this assay was examined with 64 samples of Alaska pollack roe products. In all cases, the species detected from the samples corresponded with species described on the food label.

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A method for the determination of nonvolatile amines (putrescine, cadaverine, histamine, tyramine and spermidine) in foods by solid-phase extraction and excimer-forming derivatization was investigated. Nonvolatile amines in a solid sample were extracted with 3% trichloroacetic acid, and the amines in a liquid sample were extracted with water. The extract was applied to polymer-based strong cation exchange mini-column, which was then rinsed with phosphate buffer of pH 6.8 and water. Nonvolatile amines were eluted with 100 mmol/L potassium carbonate solution. The solution was mixed with 6 mmol/L 1-pyrenebutylyl chloride solution and derivatized. Derivatives of nonvolatile amines were analyzed by LC-FLD, and the identity of the amines was confirmed by LC-MS/MS without derivatization. The limit of detection (S/N≥3) of nonvolatile amines in all samples was 0.04 μg/g, and the limit of quantitation (S/N≥10) was 0.1 μg/g. Recoveries of nonvolatile amines from fish tissues, miso, shoyu and red wine were in the range of 80.4-111%.

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We studied the simultaneous determination of acephate, methamidophos, and omethoate in animal and fishery products, their processed foods, and honey by means of liquid chromatography coupled with mass spectrometry (LC-MS). The sample was extracted with ethyl acetate in the presence of anhydrous Na₂SO₄ (and diatomaceous earth for honey). An aliquot of the crude sample extract was loaded into the GPC system, and the pesticide fraction was selectively collected. The extract was cleaned up on a PSA mini-column, and determined by a column-switching ESI-SIM mode LC-MS. Mean recoveries (2 replicates×5 days) of compounds from eleven kinds of samples, except honey, fortified at the analyte concentration of 0.05 μg/g were from 71.4% to 98.4%. The repeatability relative standard deviation values were ≤12.5%, and the intermediate reproducibility relative standard deviation values were ≤14.1%. In honey, the recoveries were improved to 97.6-98.6% by using highly purified surrogates.

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Vulnerability of children to toxic substances is of great concern due to their susceptibility and specific exposure profiles. In this study, we examined urinary 1-hydroxypyrene (1-OHP) levels in 134 kindergarten children and their mothers in order to assess exposure profiles from foods. Mean concentration of 1-OHP in children (0.083 μmol/mol-creatinine) was 1.8-fold higher than that in mothers (0.046 μmol/mol-creatinine). Nonetheless, a significant correlation was observed between 1-OHP levels in the two groups, which presumably reflected the similarities of diet between child and mother on the day before urine sampling. Moreover, intake of foodstuff, such as meat and/or fish, elevated the urinary 1-OHP levels, apparently due to high cooking temperature. These results demonstrate the importance of exposure assessment of toxic substances (in children via the diet).

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We examined the preparation method of the calibration standard for an ELISA kit for measuring crustacean protein in food products. The initial extract of the calibration standard was stabilized by addition of protease inhibitor to the extracting solution and heating at 100°C for 10 min. In accordance with the preparation procedure for calibrators, we prepared 3 lots of initial extract of calibration standard and analyzed the protein concentration and SDS-electrophoretic pattern. Single bands at 160, 41, 37 kDa and 4 bands in the range of 16-20 kDa were observed on SDS-PAGE. The range of protein concentration of the initial extract of the calibration standard was 2.74-4.10 mg/mL.

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