A direct competitive (dc)-ELISA was developed for rapid and simple determination of chlorothalonil residue in vegetables. A carboxylic acid derivative of pentachlorophenol was used to prepare an anti-chlorothalonil monoclonal antibody (MoAb) that showed adequate reactivity for dc-ELISA. Before homogenization of vegetable samples, phosphoric acid was added (vegetable–10% phosphoric acid (2 : 1, w/v)) to block enzymatic decomposition of chlorothalonil. The use of phosphate buffer (100 mmol/L, pH 7.0) minimized the influence of phosphoric acid on competitive reaction in the dc-ELISA. Working range was 0.10 to 6.0 ng/mL in the optimized dc-ELISA. The recovery of chlorothalonil spiked in cucumber and eggplant was 97.1 to 125%. The results correlated well with those obtained by HPLC analysis. The dc-ELISA could rapidly determine chlorothalonil after a simple sample preparation procedure.

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This in vivo study in rats evaluated whether Coleus forskohlii extract (CFE) taken orally interacted with tolbutamide, a hypoglycemic drug metabolized by CYP2C enzymes. Rats were fed 0%, 0.3%, 1% (w/w) CFE diet for 2 weeks, followed by 0% CFE diet for 1 day. They were then given 40 mg/kg tolbutamide by intragastric gavage. Blood glucose level was determined up to 6 h after tolbutamide administration. CFE treatment increased total CYP content and various CYP subtypes in the liver. In particular, increases in activity and protein expression were noted for the CYP2B, CYP2C, and CYP3A subtypes. CFE treatment dose-dependently attenuated both the hypoglycemic action of tolbutamide at 6 h and the plasma concentration of tolbutamide. The activity of (S)-warfarin 7-hydroxylase, a CYP2C enzyme was negatively correlated with plasma tolbutamide level, which also showed a negative correlation with the reduction of blood glucose level. These results indicate that CFE induced hepatic CYPs in rats and attenuated the hypoglycemic action of tolbutamide via a hepatic CYP2C-mediated mechanism.

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Foodborne infections with enterohemorrhagic Escherichia coli (EHEC) related to food in each step of the cooking of a Japanese barbecue have been reported in Japan. We examined the survival of EHEC during various types of cooking on a Japanese barbecue. The number of EHEC in barbecue sauce remained stable during short-term storage at low temperature. In a series of experiments on survival of EHEC on beef during cooking on an electric griddle or a gas cooktop, the population was reduced by at least 1/1,100. Although these results suggested that EHEC are effectively killed by adequate cooking, the degree of reduction of EHEC varied among types of meat and was affected by uneven cooking. Furthermore, when the same cooking equipment was used to handle meats before and after cooking, 1/500 to 1/300,000 of EHEC population of contaminated uncooked meat cross-contaminated the cooked meat. Adequate cooking of beef, including internal organs, and use of separate cooking equipment for uncooked and cooked beef are important to avoid EHEC infection caused by Japanese barbecues.

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The major fish allergen is parvalbumin, a sarcoplasmic protein. In this study, a novel lateral flow immunoassay for the detection of fish protein in food products was developed using a polyclonal antibody raised against Pacific mackerel Scomber japonicus parvalbumin. The proposed lateral flow immunoassay showed high reactivity to various fish parvalbumins, but the reactivity to bullfrog parvalbumin was very low. The detection limit of the immunoassay for fish parvalbumin was estimated to be 2.0 μg protein/g, which matches the sensitivity required in the current Japanese food labeling system. Furthermore, the lateral flow immunoassay could detect fish parvalbumin without being affected by food matrices and was applicable even to heat-denatured parvalbumin. These results showed that the lateral flow immunoassay developed in this study is specific to fish parvalbumin, and should be useful as a rapid detection method for fish protein in processed food products.

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A method for the determination of 12 statins [atorvastatin (ATOR), cerivastatin (CERI), fluvastatin (FLU), lovastatin (LO), lovastatin acid (LOA), mevastatin (ME), mevastatin acid (MEA), pitavastatin (PITA), pravastatin (PRA), rosuvastatin (ROSU), simvastatin (SIM), and simvastatin acid (SIMA)] in dietary supplements by ultra-performance liquid chromatography (UPLC) has been developed. Statins were ultrasonically extracted with 50% (v/v) methanol. Clean-up was performed using an Oasis MAX mini-cartridge column with methanol and methanol containing 0.2% (v/v) phosphoric acid as an eluting solvent. UPLC separation was performed on an ACQUITY UPLC BEH C18 column (2.1 mm i.d.×150 mm, 1.7 μm) with 0.2% (v/v) phosphoric acid aqueous solution-acetonitrile gradient. The method was validated for dietary supplements spiked with the 12 statins at the quantitation limits and 10 times the quantitation limits, and the recoveries of statins were between 89.2% and 100.9%. Relative standard deviation values of repeatability and intermediate precision were not more than 7%. The analytical method was applied to 24 commercial dietary supplements. LO and LOA were found at maximum concentrations of 4.85 mg/packet and 1.28 mg/capsule, respectively. Other statins were not detected. When a dietary supplement was consumed according to the directions on the package, the daily intake of LO was 6.74 mg. This could be dangerous to consumers because it exceeds one half of the lowest recommended daily dose of LO (10 mg).

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In Japan, a criterion value of histamine residue in food is not clearly defined and there is no official test method. We examined histamine in fish and fish products according to the food sanitation test guideline (fluorescence derivatization of histamine with dansyl chloride and quantification by LC-FL: the LC-FL method). Positive samples were confirmed by determining dansylated histamine using our developed LC-MS/MS procedure (the LC-MS/MS method) when histamine was detected. Validation was earried out according to the validation test guideline using fresh fish. Recovery tests of histamine from fresh fish spiked at the level of 20 ppm were carried out. The limit of quantification was 5 ppm. The results confirmed that our LC-MS/MS method is applicable for the inspection of fish and fish products. This LC-MS/MS method has a lower false-positive ratio and a higher selectivity than the LC-FL method.

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In this study, we established a high-sensitivity analytical method for purines in alcoholic beverages using hydrophilic interaction chromatography coupled with tandem mass spectrometry. The alcoholic beverages were hydrolyzed with perchloric acid (60%) and subjected to strong cation exchange solid-phase extraction (Bond Elut SCX). The four purine bases (hypoxanthine, adenine, xanthine, guanine) in the extracted solution were separated by hydrophilic interaction chromatography with TSKgel Amide-80 as a separation column, 10 mM ammonium formate (pH 2.0) as mobile phase A, and acetonitrile/100 mM ammonium formate (pH 2.0) (90/10) as mobile phase B. The detection of purine bases was performed by tandem mass spectrometry with ESI. The linearity of this analytical method was not less than 0.996, and the repeatability was not more than 8.4% for each purine base. The recovery was in the range of 60–105%, and the detection limit was not more than 0.005 mg/100 mL. This established method is expected to be useful for quality control and surveillance of purines in alcoholic beverages.

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An interlaboratory study was performed to evaluate a migration test method of cadmium (Cd) and lead (Pb), based on the Japanese Food Sanitation Law for glassware, ceramicware, enamelware and metal cans. Seventeen laboratories participated, and quantified Cd and Pb in eight test solutions as blind duplicates using flame atomic absorption spectrometry (AAS), graphite furnace atomic absorption spectrometry (GF-AAS), inductively coupled plasma-optical emission spectrometry (ICP-OES) or induced coupled plasma-mass spectrometry (ICP-MS). Statistical analysis revealed that the trueness, repeatability (RSD_r) and reproducibility (RSD_r) were 93–105%, 0.7–8.4% and 2.6–19.3% by using AAS, ICP-OES and ICP-MS (internal standard method). The performance of these methods is sufficient for testing specifications. However, some of the RSD_r values exceeded 10% in GF-AAS, and careful control of accuracy is required.

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