Meat derived from spent hens as well as broilers is destined for human consumption. There are many reports on the prevalence and antimicrobial resistance of Campylobacter and Salmonella in broiler meat, but few in spent hen meat. Therefore, we investigated the prevalence and antimicrobial resistance of these genera in spent hen meat collected at chicken processing plants. Campylobacter and Salmonella were isolated from 47 (92.2%) and 18 (35.5%), respectively, of breast meat derived from 51 spent hen flocks. Campylobacter jejuni accounted for 87.5% of Campylobacter isolates. The highest resistant rate in C. jejuni isolates was found for ampicillin (45.3%), followed by tetracycline (14.3%) and ciprofloxacin (14.3%). There was no Campylobacter isolate resistant to erythromycin, which is recommended as a first-choice antimicrobial for humans when Campylobacter enteritis is strongly suspected. Of Salmonella isolates, the first and second most frequent serovars were Salmonella Corvallis (30.4%) and S. Braenderup (21.7%), respectively. Of Salmonella isolates, 30.4% were resistant to streptomycin. There was no Salmonella isolate resistant to ciprofloxacin, which is one of the recommended antimicrobials for humans against Salmonella enteritis. This study shows that one third of spent hen meat is contaminated with Campylobacter or Salmonella, and administration of erythromycin or cefotaxime is an effective option for patients with Campylobacter- or Salmonella- enteritis, respectively, caused by consumption of spent hen meat.

Gibberellic acid (GA₃) is commonly used as a plant growth regulator in many food crops owing to its essential signaling functions during plant growth and development. In Japan, a threshold for administrative action for GA₃ content of 0.3 mg/kg applies in produce in which maximum residue limits have not been established. Although the threshold is based on previous studies, the GA₃ concentrations in individual foods are still unknown. Thus, we surveyed the concentrations of GA₃ in banana, cherry, and kiwi fruit on the Japanese market. We developed and validated a method for the analysis of GA₃ using solid-phase extraction and LC-MS/MS in accordance with accepted criteria of trueness, repeatability, and selectivity. The limits of detection and of quantification were determined as 0.005 and 0.05 mg/kg, respectively, in all fruits. Concentrations of GA₃ did not exceed 0.3 mg/kg regardless of ripeness, suggesting the reasonability of the current regulation of GA₃ in banana, cherry, and kiwi fruit. These findings can support prompt administrative action on these fruits, contributing to the regulation of GA₃ in Japan.

This study proposes a method to determine flubendazole and metabolite R35475 in livestock products using tandem mass spectrometry coupled with positive ion electrospray ionization. Acetone is used to extract flubendazole and metabolite R35475 from the livestock samples. These extracts were purified using an SCX cartridge column (500 mg). Furthermore, high-performance liquid chromatography was performed on an Inertsil ODS-4 column with a gradient formed using methanol and water, both of which contain 5 mmol/L of ammonium acetate. The recovery tests using bovine muscle, fat, liver, milk, and egg fortified at the maximum residue limits of analytes or 0.005 mg/kg revealed that the trueness (n=5) of flubendazole and metabolite R35475 ranged from 89.4 to 106.4% with a repeatability rate of 1.7–7.8%.

In order to quickly analyze 8 types of nonvolatile amine, such as histamine, a simple analytical method was developed. A test solution was prepared only by diluting and filtering a trichloroacetic acid extract before analysis via LC-MS/MS.

As a result of the additive recovery test with 11 types of food, including fresh seafood, seafood processed products, and other processed foods, all amines had an accuracy in the range of 70 to 120% with a repeatability of less than 15% RSD in 9 types of food. This confirmed the validity of the analytical method with the lower limit of quantification between 5 to 6 mg/kg.

We determined the fifteen types of plasticizers, including four kinds of phthalic acid esters (PAEs) used in 220 polyvinyl chloride (PVC) toys on Japanese market from 2019 to 2020. Three kinds of previously undetected types of PAEs were also detected, but not identified in this study. Di (2-ethylhexyl) terephthalate (DEHTP) was the highest detection rate in 209 soft PVC toys out of 220 toys, with 71.2% for designated toys and 88.9% for not-designated toys, respectively, showing a gradual increase from the previous reports in 2009 and 2014. On the other hand, the usages of o-acetyl tributyl citrate and adipic acid esters decreased, but the six types of PAEs prohibited to use for the designated toys in Japan were not detected in them, the usage of diisobutyl phthalate were increased. In contrast, four types of PAEs were detected in not-designated toys. Among them, the detection ratio of di (2-ethyhexyl) phthalate decreased to about 1/10. The content levels of plasticizers in per each sample were continued to keep low level from the report five years ago. These results showed that the main plasticizer used in PVC toys is DEHTP, and that the usage of other plasticizers was decreased.

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 (RSD_R), which was estimated from the inter-laboratory study, and predicted RSD_R, 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.

Five kinds of anions namely fluoride, chlorate, chlorite, nitrate and nitrite ions, and bromic acid were determined in various mineral waters (MWs), and the methods were validated. MWs are varying in the degree of hardness and contents of carbonate. When the five anions were measured based on the official method of tap water, the peak shape of fluoride ion in MWs with high degree of hardness was different from the standard solution, making it difficult to determine. The same phenomenon was also observed when bromic acid was measured. In order to achieve accurate determination, five-fold dilution with ultrapure water was carried out on the samples. With the additional step, the abnormal peak of both analytes was improved, and no difference in the retention times between standard and sample solutions was observed. The validation tests were performed using the developed methods with the additional diluting step, and the results of all target substances met the criteria of the guideline on analytical method validation for MW in Japan. Our results suggested that the methods we developed could be useful for the accurate determination of the anions and bromic acid in various MWs on the market.