An analytical method based on LC-MS/MS was developed for the determination of asulam in livestock products. Asulam in livestock products was extracted with acetone. The crude extracts were defatted by acetonitrile and n-hexane partitioning. Cleanup was carried out using a combination of ethylene diamine-N-propyl silylation silica gel (PSA) and octadecyl silylated silica gel (C18) mini columns with acidic condition. The sample solution was subjected to LC-MS/MS using an external solvent calibration curve. The average recovery (n=5) of Asulam from four types of livestock products (bovine muscle, bovine fat, bovine liver and milk) spike at the maximum residue limits (MRLs) or at a uniform limit of 0.01 mg/kg was 92.7–98.7%, with a relative standard deviation of 3.1–11.6%. The limit of quantitation of the developed method was calculated to be 0.01 mg/kg.
Ciguatera fish poisoning (CFP), one of the most frequently occurring seafood poisonings due to marine finfish consumption, mainly affects the tropical and subtropical Indo-Pacific region and the Caribbean Sea. The principal class of toxins, ciguatoxins (CTXs) from the Pacific, includes more than 20 derivatives and are classified into two groups, CTX1B and CTX3C congeners, based on their skeletal structures. As part of risk management of CFP by the Japanese government, the import of certain species of fish into Japan is prohibited. Additionally, local governments recommend rejecting certain fish species caught in Japan. In this study, we used LC-MS/MS to analyze CTXs from 18 fish specimens belonging to 7 species that had been brought to a wholesale market but were disapproved for sale because of their potential danger of CFP. CTXs were detected in four specimens of Lutjanus bohar and one specimen of Variola louti. It was estimated that the two most poisonous specimens (no. 5: 0.348 μg/kg, no. 8: 0.362 μg/kg) had a toxicity of 0.05 MU/g. Consumption of 200 g of flesh from these fish could cause CFP. Thus, the guidance of the local government to disallow the sale of these fish species in the market contributed to the prevention of CFP.Only CTX1B congeners were detected in L. bohar (specimen no. 5), which had no record of the area where it captured from. It is presumed that the origin of specimen no. 5 was the same as that of the Okinawan L. bohar because the CTX compositions were similar. In two specimens (nos. 6 and 8) from Wakayama, both CTX1B and CTX3C congeners were detected. This is the first report to reveal the CTX profile in fish collected off the Honshu island in Japan.
We evaluated an analytical method to detect pesticide residues in agricultural products through the use of a self-cleaning ion source GC-MS/MS. The self-cleaning ion source minimizes ion source contamination by ensuring that hydrogen is pumped into the source at a fixed pressure after or during measurement. When we employed our self-cleaning ion source GC-MS/MS technique to analyze pesticides residues in agricultural products, we observed that pollution of the ion source surface was considerably reduced. Good peak sensitivity was obtained for 251 pesticides, and a calibration curve with a coefficient of determination (R2) of 0.990 or higher was obtained for 253 pesticides. In the recovery test with 6 types of agricultural products, the acceptability criteria of recovery (70–120%) and standard deviation of repeatability (RSD<25%) was met in 180–221 pesticides.
The role of dietitians is important for consumers to practice self-care, which includes the use of the “Foods with Function Claims (FFC)”. In this study, a nationwide internet survey was conducted to clarify the understanding and attitudes of dietitians towards the FFC 1 year and 4 years after its introduction (Surveys were conducted in 2015 and 2019, respectively). In the survey of 1 year after the introduction, the ratio of recognition of the FFC was 98%; however, only 35% correctly understood the characteristics of the FFC. Similarly, in the survey of 4 year after the introduction, only 42% of dietitians correctly answered the characteristics. At 4 year after, 56% of dietitians currently or previously have used the FFC. The dietitians who had been consulted about the use of the FFC accounted for 22% and about the adverse events accounted for 15%. The advice they gave at the consultation differed according to their experience of the use of the FFC. Of the ones who never used the FFC, 25% referred no information sources for the FFC. The place to educate primarily working dietitians needs to be prepared to let them provide appropriate information to consumers to support self-care including the appropriate use of the FFC.
Marine pufferfish Takifugu exascurus is not approved for human consumption due to the lack of information on its toxicity. To clarify the toxicity of T. exascurus, ten live specimens were collected from the Sea of Kumano, Japan, and the toxicity and tetrodotoxin (TTX) concentration were determined using mouse bioassay and high performance liquid chromatography-fluorescence detection (HPLC-FLD), respectively. Toxicity was observed in the skin, liver, and ovaries, but the testes and muscle were non-toxic (<10 MU/g). On the other hand, HPLC-FLD revealed that TTX was detected in the muscle in two of the 10 specimens (1.4 and 1.5 MU/g). Based on the results, TTX is the main toxic component contributing to toxicity in T. exascurus.
A LC-MS/MS simultaneous analytical method for screening 191 pesticide residues in limes had been developed and validated. Pesticides were extracted with acetonitrile from samples. Then mixed salts, which were anhydrous magnesium sulfate for dehydration, sodium carbonate for adjusting pH, and sodium chloride for salting out, were added to the sample. After centrifugation, supernatant was transferred to a tube. The sample solution was cleaned up using solid phase extraction (SPE) with C18/GC/PSA for the determination by LC-MS/MS. The developed method was improved the recovery rate of thiabendazole, which had a low recovery rate by the conventional method. Validation study, which was following the guidelines of the Ministry of Health, Labor and Welfare, were carried out at 0.01 and 0.1 μg g−1 to evaluate the method. The results of 175 pesticides out of 191 were with satisfactory. A total of 19 imported lime samples sold in Tokyo was analyzed to evaluate the method, then 18 samples contained pesticide residues below MRLs. The developed method is applicable for detection of pesticide residues in lime.