[Fate of Organophosphorus Flame Retardants in Polished Rice during the Cooking Process].

The fate of organophosphorus flame retardants (PFRs) in polished rice during the cooking process was examined. After adding PFRs to polished rice (500 ng/g), the rice was washed with water and cooked in a rice cooker. Among the seven kinds of PFRs, approximately 68-86% of the PFRs residues were removed after washing with water three times. In the first washing with water, approximately 50-70% of the PFRs residues were removed from rice. By the subsequent heating in an electric rice cooker or in a microwave rice cooker, the removal rates of PFRs in the cooked rice were 74-94 and 78-96%, respectively. The removal rates in musenmai (500 ng/g) which need not to wash before cooking were lower than those in the washed rice. In the cooked musenmai, 10-50% of the PFRs residues were removed after heating in the electric rice cooker, and 10-70% were removed in the microwave rice cooker. The washing process is effective to reduce the intake of PFRs from rice.

[Adsorption of Airbone Organophosphorus Flame Retardants on Polished Rice Stored in a House].

In order to clarify the actual situation of indoor pollution to polished rice with organophosphorus flame retardants (PFRs) which are ubiquitous in the indoor environment, the pollution of PFRs to polished rice stored in a house for a week was investigated. The survey covered 64 ordinary families in the Osaka region. We analyzed six typical PFRs in 37 rice samples in 2015, and ten typical PFRs in 27 rice samples in 2016. Polished rice was homogenized with acetone-hexane and defatted by hexane-acetonitrile partition. Quantitative analysis for PFRs was performed by GC-FPD. The detection frequency of PFRs in the rice samples was 35/37 in 2015 and 27/27 in 2016. The highest values were 160 ng/g for TCEP, 500 ng/g for TCIPP and 430 ng/g for TBEP. The concentration ratio of each detected PFR in the polished rice samples was different in each house. In the analysis of 16 polished rice samples which were stored in the home, PFRs were detected in ten samples regardless of the storage methods. PFRs were detected from 12 out of 16 commercial brown rice samples. This result suggested that they were polluted during distribution and storage process of them.

[Chlorpyrifos-Methyl, Pirimiphos-Methyl and Fenitrothion Residues in Commercial Wheat Products].

We measured the concentrations of organophosphorus pesticide （chlorpyrifos-methyl, pirimiphos-methyl and fenitrothion） residues in domestic and imported commercial wheat products （flour, noodles, cookies） collected from 2008 to 2016. Chlorpyrifos-methyl and fenitrothion in domestic flour samples were detected in 16 out of 34 samples at levels of ＜0.001 to 0.016 ppm, and in 14 out of 34 samples at levels of ＜0.001 to 0.004 ppm. Chlorpyrifos-methyl was detected in 22 out of 38 domestic cookies at levels of ＜0.001 to 0.054 ppm （median: 0.001 ppm）. Relatively high concentrations of chlorpyrifos-methyl （0.005 to 0.054 ppm） were found in six domestic cookies containing wheat bran. Pirimiphos-methyl was detected in 32 out of 68 cookies from foreign countries at levels of ＜0.001 to 0.11 ppm. Pirimiphos-methyl was detected frequently in products imported from Europe.

[Determination of S-421 in Commercial Fish and Shellfish].

S-421 is a synergist of pyrethroid and organophosphorus pesticides, which are used as termiticides or household insecticides. S-421 is stable and ubiquitous in the environment. Here we describe the concentrations of S-421 in domestic and imported commercial fish collected from 2009 to 2016. Samples were extracted with acetone/hexane and S-421 was purified on a silica gel column. Quantitative analysis was performed by GC-ECD. S-421 was detected in 78 of 116 samples of domestic fish and shellfish at levels of <0.2 to 2.6 ng/g (mean: 0.4 ng/g), and in 69 of 102 imported samples at a level of <0.2 to 1.5 ng/g (mean: 0.4 ng/g). The concentrations of S-421 in fish were lower than those of p,p'-DDE and similar to those of ß-HCH.

[Rapid analysis of aflatoxins in raw peanuts, corn, buckwheat and red pepper by a new mini-column cleanup and HPLC using post-column photochemical derivatization system].

A rapid and clean method for the analysis of aflatoxins (AFs) was developed by using a new column and post-column photochemical derivatization HPLC with fluorescence detection. The new cleanup column consisted of magnesia and basic alumina poured on the top of a commercial multi-functional mini-column. It was extremely effective for the cleanup of AFs from raw peanut, corn, buckwheat and red pepper. Fluorescent substances, which interfered with the analysis of AFs from corn, were completely absorbed at the top of the magnesia layer. Recoveries of AFs (B1, B2, G1, G2) added to raw peanuts, corn, buckwheat and red pepper were over 80% at two levels of fortification (higher level: 10, 3, 10, 3 ng/g, respectively, lower level: 1.0, 0.3, 1.0, 0.3 ng/g, respectively). Coefficients of variation were smaller than 12%, except the lower fortified level for red pepper. Limits of detection for AFs in raw peanuts, corn and buckwheat were 0.3 ng/g for B1 and G1, and 0.1 ng/g for B2 and G2. Those in red pepper were 0.5 ng/g for B1, B2, G1 and G2.

[Inhibitory effect of zinc on beta-hexosaminidase release from RBL-2H3 cells by synthetic chemicals].

The effects of foods and chemicals related to food hygiene on degranulation were evaluated using a method for assaying the enzyme activity of beta-hexosaminidase as an index of chemical mediator release from RBL-2H3 cells in vitro. Using a previously developed assay system, we had found a large number of inhibitors and promoters of degranulation of RBL-2H3 cells. In the present study, we examined the inhibitory effect of zinc chloride on the degranulation (beta-hexosaminidase release) from RBL-2H3 cells with or without antigen in the presence of the degranulation-promotive chemicals, namely, 4 food additives, 7 pesticides and 2 veterinary drugs. These promotive chemicals were classified into two types on the basis of inhibitory profile by zinc chloride: 1) those which showed marked degranulation-inhibitory action when the cells were stimulated with antigen, such as butylhydroxyanisole, dibutylhydroxytoluene, EPN, cis- and trans-permethrin, prothiofos, pyridaben, terbufos, 2) those which showed marked degranulation-inhibitory action whether the cells were stimulated with antigen or not, such as butyl p-hydroxybenzoate, o-phenylphenol, bitertanol, salinomycin. In conclusion, zinc had a dramatic inhibitory effect on enhanced degranulation induced by synthetic chemicals in vitro.

[Occurrence of an organochlorine synergist S-421 in fish and shellfish].

S-421 is a synergist for pyrethroid and organophosphorus pesticides, and is widely used in termiticides or commercial household insecticides. S-421 is mutagenic, stable and ubiquitous in the environment, and has been detected in household dust, surface water, sediments and rain-water. Here we describe the concentration of S-421 residues in domestic and imported fish collected in Osaka. S-421 was extracted with acetone/hexane, purified through silica gel 40 and quantified by ECD-GC. S-421 was detected in 36 out of 44 samples of domestic fish and shellfish analyzed, at a level of < 0.2 to 2.3 ng/g (mean: 0.6 ng/g), and in 27 out of 43 imported samples at a level of < 0.2 to 1.0 ng/g (mean: 0.2 ng/g). The levels of S-421 detected in fish were lower than those of DDTs and almost the same as those of HCHs. More attention should be paid to the behavior in the environment of S-421, as well as other persistent organochlorine pollutants, such as HCHs, DDTs and chlordane.

[Effects of veterinary drugs on beta-hexosaminidase release from rat basophilic leukemia cells (RBL-2H3)].

Little is known about the effects of residual veterinary drugs on the allergic reaction, except for the antigenicity of antibiotics and synthetic antimicrobials. Therefore, 59 kinds of veterinary drugs were investigated for their effects on the IgE receptor-mediated beta-hexosaminidase release from RBL-2H3 cells as an index of immediate allergic reaction. We found that the antibiotics chlorotetracycline, doxycycline, monensin, the synthetic antimicrobial pyrimethamine and the steroid hormone testosterone inhibited beta-hexosaminidase release. Most of the veterinary drugs showed no action, though the ionophores lasalocid, salinomycin and the steroid hormone hexestrol promoted beta-hexosaminidase release from injured cells. Based on the residual levels of these drugs and the frequencies of detection in actual food samples, it seems unlikely that these drugs have any immediate allergic effect in practice.