Publications by authors named "Masato Yoshimitsu"

Herein, we devise a method to detect methylmercury (MeHg) in fish and shellfish food samples using solid-phase extraction. We draw from the principles of the "QuEChERS" method, eliminating the need for hazardous organic solvents and employing general-purpose gas chromatography-mass spectrometry (GC-MS) equipment. The use of acetonitrile during extraction prevents emulsion formation, which could otherwise disrupt MeHg recovery.

View Article and Find Full Text PDF

After washing the cooking utensils used to prepare liquid batter, flour may remain in the scrubbing sponge. Secondary contamination of cooking devices with wheat allergens is a concern if such scrubbing sponges are used to clean other equipment. Therefore, in this study, bowl washing with detergent, using a scrubbing sponge was evaluated as a cleaning method following liquid batter cooking.

View Article and Find Full Text PDF

A simple, universal method to quantify soil methylmercury (MeHg) is not available. Here, we developed a solid-phase extraction-based method using gas chromatography mass spectrometry. MeHg was purified from the soil matrix using an optimized solid-phase extraction method, which reduced the use of organic solvents and eliminated the requirement for harmful reagents.

View Article and Find Full Text PDF

As an analytical method for aflatoxins in foods, the analytical method based on the notification by the director of the Food Safety Department, Pharmaceutical and Food Safety Bureau, Ministry of Health, Labour and Welfare (August 16, 2011) has been established. In order to improve the operability and analytical performance of the conventional method, this study aimed to construct an improved method that optimized selection of immunoaffinity column (IAC) and purifying condition, and omitted evaporation after the purification with IAC. In the recovery test performed by adding 2.

View Article and Find Full Text PDF

Hen's egg white allergens, namely Gal d 1-4, cause food allergies worldwide and their intake must be strictly controlled by allergic individuals. However, an efficient method for quantifying these allergens is currently unavailable. We aimed to develop an LC-MS/MS method for simultaneous Gal d 1-4 quantification.

View Article and Find Full Text PDF
Article Synopsis
  • Researchers developed a quick and straightforward LC-MS/MS method to analyze six fungicides in citrus fruits, including some newly approved after 2011.
  • The method streamlined extraction and purification by combining steps, using a specific volume of sample extracts and acetonitrile for efficient results.
  • Validation showed high recovery rates and low variability in results, aligning with Japanese pesticide regulations, confirming the method's effectiveness for testing commercially sold citrus fruits from 2017 to 2019, revealing no issues with labeling or residue levels.
View Article and Find Full Text PDF

Oranges are consumed worldwide; however, they contain Cit s 2, a major profilin allergen. We aimed to reduce Cit s 2 levels by preparing mixed orange fresh juice with pineapple, as a convenient method for any kitchen. Cit s 2 levels in orange extracts digested with pineapple extract and its protease bromelain were evaluated with quantitative enzyme-linked immunosorbent assay.

View Article and Find Full Text PDF

The total mercury (T-Hg) and methylmercury (MeHg) concentrations in red snow crabs (Chionoecetes japonicus) caught off the coast of Japan were analyzed. The T-Hg concentration ranged from 0.03 to 0.

View Article and Find Full Text PDF

We carried out a collaborative study in six laboratories to confirm the universality of the enhancing effect of co-existing reference pesticides on the GC-MS peak response to a target pesticide (malathion, procymidone, or flucythrinate). First, we confirmed the response enhancement of the target pesticides with increasing numbers of co-existing reference pesticides in solution. Then, using diluted green soybean matrix, we analyzed the target pesticides with two types of matrix-matched calibration, containing the target pesticides or 166 other pesticides.

View Article and Find Full Text PDF

Polyethylene glycol 300 is commonly used as a base material for "analyte protection" in multiresidue pesticide analysis via gas chromatography-mass spectrometry. However, the disadvantage of the co-injection method using polyethylene glycol 300 is that it causes peak instability in α-cyano pyrethroids (type II pyrethroids) such as fluvalinate. In this study, we confirmed the instability phenomenon in type II pyrethroids and developed novel analyte protectants for acetone/n-hexane mixture solution to suppress the phenomenon.

View Article and Find Full Text PDF

Background: Since wheat flour, a cause of food allergy, tends to disperse rapidly in air, it can unintentionally mix other foods during the sieving process. Our aim was to analyze the dispersal of wheat flour dust in air in order to prevent unintentional mixing.

Methods: We measured particle size distribution of wheat flour, photographed the scattered flour for 60 seconds every 10 seconds after sieving through three types of flour sifter, constructed a velocity vector diagram of flour dust dispersal by each type of sifter, and measured the distance of wheat allergen dispersal over 20 minutes using a petri dish and immunochromatographic test.

View Article and Find Full Text PDF

The aim of this study was to develop a monoclonal antibody (mAb)-based enzyme-linked immunosorbent assay (ELISA) for the quantification of a major allergen (Cit s 2) in fresh and processed oranges. Purified recombinant Cit s 2 (rCit s 2)-small ubiquitin-like modifier (SUMO) was used for the production of mAbs. In the optimized ELISA, the recovery of rCit s 2 from Navel oranges or orange juice was 107-132%, and the intra- and inter-assay coefficients of variation were 3.

View Article and Find Full Text PDF
Article Synopsis
  • The study identifies a phenomenon called the "matrix-like effect," where adding multiple pesticides to a solution unexpectedly enhances the detection of certain pesticides during gas chromatography analysis.
  • Using five specific pesticides and four internal standards, the researchers found that the detection responses of these pesticides significantly increased with the addition of up to 166 other pesticides in the mixture.
  • The findings indicate that traditional internal standards may not effectively account for this matrix-like effect, suggesting that the presence of multiple pesticides could complicate the analysis and interpretation of results.
View Article and Find Full Text PDF
Article Synopsis
  • The matrix-matched standard solutions approach is commonly used in GC-MS/MS for estimating multi-residue pesticides, but preparing these solutions is very time-consuming.
  • A new method using general matrix standard solutions (PEG-VFJm) incorporating polyethylene glycol, vegetable-fruit juice extract, and triphenyl phosphate was developed to streamline this process.
  • Validation tests showed that while the matrix-matched method accurately detected 144 to 158 pesticides in potatoes, spinach, and apples, the PEG-VFJm method also performed well, identifying 129 to 149 pesticides, indicating it could allow for quicker pesticide analyses.
View Article and Find Full Text PDF

The number of students with food allergy is currently increasing. Moreover, the unintentional mixing or accidental ingestion of allergy-causing food materials in school lunches has attracted great attention. The aim of this study was to verify the current status of elementary school lunch provision for students with food allergy.

View Article and Find Full Text PDF