Food Hygiene and Safety Science最新文献

The growth and gas production test for Escherichia coli in the microbiological examination of food additives is stipulated in the ninth edition of Japan's Specifications and Standards for Food Additives (JSFA) and described as a part of the "Confirmation Test for Escherichia coli" in "Microbial Limit Tests" in the same manuscript. The growth and gas production test for E. coli indicated that the positive or negative of "gas production and/or turbidity" in EC broth should be confirmed after incubating at 45.5±0.2℃ for 24±2 h. If both gas production and turbidity are negative, the culture is additionally incubated up to 48±2 h to determine E. coli contamination. The internationally referenced Bacteriological Analytical Manual of the U.S. FDA had revised the incubation temperature in tests for coliforms and E. coli from 45.5±0.2℃ to 44.5±0.2℃ in 2017. Therefore, we conducted research in anticipation of this temperature change being reflected in the microbiological examination of the JSFA. We used seven EC broth products and six food additives across eight products that are available in Japan in order to compare the growth and gas production at temperatures of 45.5±0.2℃ and 44.5±0.2℃ of E. coli NBRC 3972, which is designated as the test strain in JSFA. Both with/without food additives, the number of EC broth products in which medium turbidity and gas production by the strain were positive in three out of three tubes at all test times was greater at 44.5±0.2℃ than at 45.5±0.2℃. These results suggest that the growth and gas production test for E. coli could be more appropriately conducted by incubation at 44.5±0.2℃ in the "Confirmation Test for Escherichia coli" for E. coli in the JSFA in comparison to 45.5±0.2℃. Furthermore, there were differences in the growth and gas production of E. coli NBRC 3972 depending on the EC broth product used. Therefore, the importance of "Media growth promotion test" and "Method suitability test" in the ninth edition of the JSFA should be emphasized.

A validation study was performed on the modified analytical method for the migration solution of heptane, 20% ethanol and 4% acetic acid for the determination of bisphenol A migrating from polycarbonate food apparatuses, containers, and packaging. The analytes for the method were bisphenol A, phenol and p-tert-butylphenol. The repeatability, within-laboratory reproducibility and trueness of the method was estimated in the range of 0.2-1.8%, 0.4-2.6% and 95-102% respectively. These results showed that the method is useful as an analytical method for the migration solution of heptane, 20% ethanol and 4% acetic acid. Furthermore, the applicability of the determination methods with a fluorescence detector was verified. As a result of the validation study, the repeatability, within-laboratory reproducibility and trueness of the method was estimated in the range of 0.1-2.9%, 0.2-3.1% and 94-101% respectively. It was confirmed that the measurement with a fluorescence detector is also available.

Simple identification using a color reaction was applied to investigate poisoning, putatively caused by Omphalotus guepiniformis. Some leftover uncooked mushrooms had turned turquoise green when a beam reagent (5 w/v% potassium hydroxide ethanolic solution) was dripped onto the mushroom pileus. Furthermore, ethanol extract of the mushrooms exhibited the same color reaction. Then, illudin S, a toxic compound contained in O. guepiniformis, was detected in uncooked leftover mushrooms using LC-MS/MS analysis. Therefore, this case was inferred as caused by O. guepiniformis. These results indicate the identification method described above as useful for screening tests for investigating food poisoning caused by O. guepiniformis.

A simple and reliable analytical method has been developed for the determination of pantothenic acid in food. For the high-protein food, 20 mL of water was added to 2 g of sample, and after homogenization extraction, 1 mL of 15% zinc sulfate solution was added, mixed well, centrifuged, and the supernatant was filtered to make the test solution. For the low-protein food, 20 mL of 1% formic acid solution was added to 2 g of sample, homogenized, extracted, centrifuged, and the supernatant was filtered to make the test solution. The HPLC separation was carried out on a L-column2 ODS column with 0.02 mol/L phosphate solution (pH 3.0)- acetonitrile (95 : 5) as the mobile phase, and detected at 200 nm. The LC-MS/MS conditions were L-column2 ODS as the separation column, 5 mmol/L ammonium formate (containing 0.01% formic acid)-methanol (85 : 15) as the mobile phase, and multiple reaction monitoring (MRM) was used for detection. The recoveries of pantothenic acid in milk powder and nutritional food products were more than 88% with high precision. As a result of analyzing commetrcially available foods labeled as containing pantothenic acid, analytical values almost identical to the labeled values were obtained, and a high correlation was observed between the values obtained by HPLC and LC-MS/MS.

Benzoic acid (BA) is typically found in natural food; therefore, naturally occurring BA must be distinguished from added BA preservatives. In this study, we investigated BA levels in 100 samples of fruit products and their fresh fruits as raw materials using dialysis and steam distillation approaches. BA was detected in the range (minimum-maximum) of 2.1-1380 μg/g and 2.2-1950 μg/g in dialysis and steam distillation, respectively. Steam distillation indicated higher BA levels than dialysis.

In general, nitrite in food is extracted under slightly alkaline conditions, deproteinized, and analyzed by a colorimetric method using color development by diazotization. However, depending on the sample, the sample solution may become cloudy and difficult to filter by the deproteinization treatment of the analytical method. Recently, an improved analytical method that solves these problems has been reported. Therefore, a validation study was performed on the improved analytical method was performed. The concentrations of sodium nitrite added to cod roe, fish sausage, and ham, which were not labeled with sodium nitrite, were set at the upper limits of the standards for use. We set the target values of 70-120% for trueness, less than 15% for intralaboratory reproducibility, and less than intralaboratory reproducibility for repeatability. As a result, the target values were met for the three samples verified: 88-92% for trueness, 2.0-3.0% for repeatability, and 3.2-4.3% for intralaboratory reproducibility. In addition, an interlaboratory study was conducted by eight institutes on the improved analytical method for nitrite. At each institution, sodium nitrite was added to the same three samples as in the validation study, at concentrations equivalent to twice the lower limit of quantification and the upper limit of the standards for use and analyzed in triplicate. The estimated trueness from the obtained analyses ranged from 82 to 95%, the repeatability ranged from 2.3 to 5.8%, and the inter-room reproducibility ranged from 3.5 to 11%. Thus, the improved analytical method could be useful for determining nitrite in foods.

This study aimed to characterize the adverse events of dietary supplements provided by medical professionals and to examine whether there are challenges when applying each case to the causality evaluation algorithm. Data from 290 individual cases collected by the Tokyo Metropolitan Government in cooperation with the Tokyo Medical Association and Tokyo Pharmaceutical Association were analyzed. The causality evaluation algorithm that was used in this study was reported previously. Female patients accounted for 73% of those who experienced adverse events. Both male and female patients who had adverse events were in their 60s and 70s. Many of the participants had underlying diseases and aimed to improve their medical conditions. Furthermore, skin symptoms were the most common. Many of the supplements were made from natural substances, with an average of 7.7 ingredients in each product. More than half of the products were used for less than one month. In most cases, symptoms improved after discontinuation of the products or after the administration of medications. When each event was applied to the causality assessment algorithm, it was necessary to understand the information as follows: in cases of product discontinuation with simultaneous medications recovery was not concluding the product discontinuation, and the physician's judgement should be place as objective evidence. The algorithm was successfully applicable to cases provided by medical professionals and the evaluated results for all cases were 30% possible and 62% highly possible. The evaluated results indicate the relationship between products/ingredients and the symptom, and by adding information on the symptom and its severity, it is possible to clarify the phenomenon to be noted.

For the analysis of nitrite ions in food, the stabilities of nitrite ions in meat products and their standard solutions were evaluated. Nitrite is easily oxidized or reduced; hence, products with standard solutions or colour retention agent must be carefully handled. To assess the stability and decreasing trend of nitrite, we examined the storage stability of standard solutions using calibration curves, the time course of nitrite in chopped meat products stored under different conditions, and the time course of nitrite in the sample solutions. Regarding calibration curves, the storage stability was determined for standard solutions that were prepared with ultrapure water at concentrations of 0.025 and 0.4 μg/mL and were stored at 5℃ for one year. The results revealed no changes in concentration of any solution over time, suggesting that no readjustments to the standard solution concentration were necessary before testing until one year after their preparation. Time course of nitrite in chopped meat products stored under different conditions showed a significant decrease in nitrite in refrigerated storage (5℃), whereas stability of nitrite was maintained for up to 1 day in frozen storage (-20℃) and for 14 days in frozen storage (-40℃). The time course of nitrite in the sample solutions showed that the quantitative values of nitrite in the extract remained unchanged within one week of extraction for the meat products tested in the study.