An analytical method based on LC-MS/MS was developed for the determination of chlorothalonil metabolite I in livestock products. Chlorothalonil metabolite I 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 silica gel (SI) 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 chlorothalonil metabolite I from five types of livestock products (cattle muscle, cattle fat, cattle liver, milk and egg) spike at the maximum residue limits (MRLs) or at a uniform limit of 0.01 mg/kg was 97.1–102.9%, with a relative standard deviation of 1.4–6.8%. The limit of quantitation of the developed method was calculated to be 0.01 mg/kg

A novel method was developed for quantification of bisacuron (BC) and dehydrozingerone (DZ), the functional component of turmeric (Curcuma longa.L)-containing foods, using a relative molar sensitivity (RMS) method based on the combination of HPLC-UV and ¹H-NMR. The RMSs of BC and DZ using 4-hydroxybenzoic acid ethyl ester (HBE) as the internal standard were calculated to 1.66 and 2.55, respectively. Analysis of fourteen beverage products showed the high correlations between the concentrations of BC and DZ quantified by the RMS method and those quantified by absolute calibration curve method. A collaborative study was conducted by four laboratories on one beverage and one tablet products. The repeatable relative standard deviation (RSD_r) of intra-laboratories ranged from 0.7 to 1.7%, and the reproducible relative standard deviation (RSD_R) of inter-laboratories ranged from 2.0 to 7.3%. The RMS method enabled the quantification of analytes for which difficultly obtain standard materials such as BC and DZ, using an internal standard for which obtain routinely readily available. This RMS method is expected to be applied to quality control for food products containing turmeric.

Citreoviridin (CTV) is a mycotoxin produced by various fungi, including Penicillium citreonigrum. One of the toxicities reportedly associated with CTV is neurotoxicity. CTV is also suspected to be associated with acute cardiac beriberi (also known as “Shoshin-kakke”) and Keshan disease, which can have adverse effects on the heart, so the in vivo and in vitro toxicity of CTV on the heart or cardiomyocytes in experimental animal models have been reported. However, the toxicity of CTV for the human heart, especially its electrophysiological effect, remains poorly understood. Therefore, to investigate the electrophysiological effect of CTV on the human cardiomyocytes, we conducted a multi-electrode array (MEA) using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). The MEA revealed that 30 μmol/L of CTV stopped the beating of hiPSC-CMs, and the field potential duration and first peak amplitude were shortened at 10 μmol/L. Before the hiPSC-CMs stopped beating, the length of the inter-spike interval varied two- to four-fold. These results demonstrated that CTV induced an electrophysiological disturbance on human cardiomyocytes. This is first paper to elucidate the electrophysiological effect of CTV on human heart directly and may aid in analyzing the risk associated with CTV to ensure food safety.

We have developed a method for determination of the species of origin of biological foreign substances using proteomics analysis technology. That is, the amino acid sequence of the tryptic digested product of the protein extracted from the foreign substance is determined by high-resolution LC-MS, and the amino acid sequence is collated with a public protein database to determine the origin species of the foreign substance. As a result of testing meat (beef, pork, chicken) and egg (chicken, quail) from known origin as simulated foreign substances, we were able to find species-specific amino acid sequences for each species, suggesting that the developed method is useful for species discrimination of a foreign substances that have been heat-treated with retort, this method is potentially useful to complement DNA analysis, for determination of the species of origin of foreign substances.

We experienced a pufferfish poisoning case where no food residue was available to detect a causative agent. However, tetrodotoxin (TTX) was detected in vomit and urine samples from a patient using LC-MS/MS. Furthermore, we found a significant matrix effect in this analysis, indicating that the retention time of vomit and urine was not identical to the TTX standard solution and measured values multiplied by the dilution factors were not constant. Elimination of this matrix effect was attained by dilution of samples based on the retention time of the TTX standard solution, i.e., 10-time dilution of vomit test sample for LC-MS/MS analysis or 100–200-time dilution of urine one. Further research on urine analytical methods revealed that when TTX concentrations were too low to identify its peak on a chromatogram, TTX could be identified through a dilution procedure. It also showed that the application of the matrix-added TTX standard solution was effective for quantitative analysis under the influence of the matrix.