[Inter-laboratory Study on the Modified Methods for Analyzing Bisphenol A Content for Migration Tests from Polycarbonate Food Apparatuses, Containers, and Packaging].

An inter-laboratory study involving 24 laboratories was conducted to validate the modified analytical method for the migration solution of heptane for the determination of bisphenol A migrating from polycarbonate food processing materials. In this study, two concentrations of samples were blindly coded. Each laboratory determined the analyte (bisphenol A, phenol and p-tert-butylphenol) concentration in each sample according to the established protocol. The obtained values were analyzed statistically using internationally accepted guidelines. Horwitz ratios were calculated based on the reproducibility relative standard deviation (RSDR), which was estimated from the inter-laboratory study, and predicted RSDR, which was calculated using the Horwitz/Thompson equation. Horwitz ratios of the two samples ranged from 0.15 to 0.37 for the three compounds, meeting the performance criteria of less than 2 set by the Codex Alimentarius for analytical method approval. These results showed that this modified analytical method shows good performance as an analytical method for the migration solution of heptane.

[Inter-laboratory Study on the Modified Method Assessment for the Determining Methanol Content in Kitchen Detergents].

We modified a method for determining methanol content in detergents used in kitchens. Furthermore, an inter-laboratory study was conducted in 10 laboratories to validate the modified method. In this study, two concentrations of samples were blindly coded. Each laboratory determined the methanol content in each sample according to a protocol. The determined values were statistically analyzed according to an international harmonized guideline. HorRat values were calculated based on the reproducibility relative standard deviation (RSDR) which was estimated from the interlaboratory study, and predicted RSDR calculated from the Horwitz/Thompson equation. The HorRat values of the two samples were 0.8 and 1.8, meeting the performance criteria of less than 2 set by the Codex Alimentarius for analytical method approval. These results confirm that this modified analytical method shows good performance as an analytical method for determining methanol content in kitchen detergents.

[Proficiency Testing Schemes for Food Nutrition Analysis in Japan (2017-2018)].

This paper deals with proficiency testing schemes for food nutrition analysis in Japan. In schemes in 2017 and 2018, 65 and 73 organizations participated, respectively, and more than 70% of the participants were public organizations responsible for a nutrition-labeling compliance test. The food matrices were pork and chicken sausages, and analytes were protein, fat, ash, moisture, carbohydrate, energy, sodium, salt equivalent, calcium (2018 only), and iron (2018 only). The organizations reporting inadequate laboratory values in one or more nutrients for mandatory declaration (energy, protein, fat, carbohydrate, or salt equivalent) were 11 and 15% of all organizations and 9 and 13% of public organizations in the 2017 and 2018 schemes, respectively. The approximate relative standard deviations for proficiency assessment (RSDr) were as follows: protein, 2%; fat, 3%; ash, 2%; moisture, 0.5%; carbohydrate, 9%; energy, 1%; sodium (salt equivalent), 4%; calcium, 7%; and iron, 7%. Notably, the large RSDr value for carbohydrate may cause inconsistency among laboratories in compliance tests for foods containing several grams or less of carbohydrate per 100 grams.

Nasal instillation of nanoparticle-rich diesel exhaust particles slightly affects emotional behavior and learning capability in rats.

In the present study, in order to reveal novel adverse effects of ultrafine particles (UFP) on the central nervous system, the effects of nanoparticle-rich diesel exhaust particles (NRDEP; count mode diameter, 21.45 nm) on emotional behavior, learning capability and brain neurotransmitter levels were studied in rats by intranasal instillation (iNI). NRDEP (10 and 50 µg/rat) was instilled into 2-week old infant, male rats once a week for 4 weeks. Spontaneous motor activity measured was observed to be inverse to the dose level. In active avoidance tests using a shuttle box, NRDEP-treated animals showed a lower avoidance performance than control animals given air-instillation. The levels of dopamine and its metabolite (DOPAC) in the medial mammillary nucleus of the brain tended to be lower in the NRDEP-treated animals. From these results, although the effects of NRDEP by iNI on the emotionality and the brain neurotransmitter levels were not fully clear, the results obtained by avoidance testing suggested involvement of UFP in learning capability.

Tracheal instillation of diesel exhaust particles component causes blood and pulmonary neutrophilia and enhances myocardial oxidative stress in mice.

The influences of inhaling particulate air-pollutants on hematopoiesis and myocardial oxidative stress were investigated in mice by intratracheal instillation (IT) of diesel exhaust particles (DEP), its dichloromethane soluble-component (DMSC) or residual particle-component (RPC). After IT, time courses of cytokine levels in bronchial alveolar lavage fluid (BALF), peripheral blood cell count, myocardial myeloperoxidase (MPO) activity and myocardial chemokine levels were observed for 24 hr. RPC caused sustained blood neutrophilia while that caused by DEP and DMSC was transient. RPC also caused sustained elevations of granulocyte colony-stimulating factor (G-CSF) and interleukin (IL)-6 levels in BALF. Furthermore, IL-1beta level in BALF in the RPC group was significantly elevated at 24 hr after IT. Significant positive correlations were observed between blood neutrophil count and IL-6/G-CSF levels in BALF. MPO activity in the myocardium was increased by RPC at 12 and 24 hr after IT while the activities in the kidney and the liver were not affected. Significant correlation was also observed between myocardial MPO activity and blood neutrophil count at 12 hr after IT, for all three substances. From these results, it was concluded that particle component of DEP may enhance myocardial oxidative stress via blood neutrophilia and the elevation of cytokine levels in BALF.