Food Hygiene and Safety Science最新文献

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.

The conventional analysis method has problems with extraction efficiency, operability, and reproducibility. In this study, we attempted to solve these problems and improve the analytical method to obtain sufficient extraction efficiency and good operability and accuracy. The conventional method was able to get sufficient extraction in dried meat products, where the extraction efficiency of the conventional method was low, by increasing the concentration of sodium hydroxide solution at the time of homogenization. Suction filtration after adding the defoaming agent was added allowed for accurate volume adjustment. The turbidity of the extract caused by insufficient addition of zinc acetate solution was removed by increasing the amount of zinc acetate solution that was added. Turbidity caused by starch was removed by adding pancreatin. The RSD of the quantitative values was improved by adding sodium hydroxide solution and 80-90℃ water and immediately homogenizing. Furthermore, by changing the dilution factor of the extract solution in the colorimetric method, the inhibition of coloration by reducing substances was suppressed, and more accurate quantitative values could be obtained than with the conventional method. The recovery rate was 78.5-105% (RSD 0.7-5.8%), which was a good result. This method was considered to be a useful analytical method that can contribute to improving the inspection accuracy of nitrite ion analysis.

A simple method of identification using a color reaction was developed for Omphalotus guepiniformis. Only Omphalotus guepiniformis turned turquoise green. Other edible mushrooms resembling the mushroom did not change color when the beam reagent (5 w/v% potassium hydroxide ethanolic solution) was dripped onto the mushroom pileus. Furthermore, ethanol extract and mock cooking products of this mushroom exhibited the same color reaction. These results demonstrate this method as useful for identifying Omphalotus guepiniformis during mushroom hunting or during investigations of food poisoning.

A simple and sensitive method for the determination of moenomycin A residues in livestock products using LC-MS/MS was developed. Moenomycin A, a residual definition of flavophospholipol, was extracted from samples with a mixture of ammonium hydroxide and methanol (1 : 9, v/v) preheated at 50℃. The crude extracted solutions were evaporated and purified by liquid-liquid partitioning between a mixture of ammonium hydroxide, methanol and water (1 : 60 : 40, v/v/v) and ethyl acetate. The alkaline layer was taken, and cleaned up using a strong anion exchange (InertSep SAX) solid phase extraction cartridge. The LC separation was performed on an Inertsil C8 column with liner gradient elution using 0.3 vol% formic acid and acetonitrile containing 0.3 vol% formic acid. Moenomycin A was detected using tandem mass spectrometry with negative ion electrospray ionization. Recovery tests were conducted using three porcine samples (muscle, fat and liver) and chicken eggs. Samples were spiked with moenomycin A at 0.01 mg/kg and at the Japanese Maximum Residue Limits (MRLs) established for each sample. The trueness ranged from 79 to 93% and precision ranged from 0.5 to 2.8%. The limit of quantification (S/N≥10) of the developed method is 0.01 mg/kg. The developed method would thus be very useful for regulatory monitoring of flavophospholipol in livestock products.

This study aimed to investigate the prevalence and antimicrobial sensitivity of Campylobacter jejuni and Campylobacter coli in retail meat (chicken, beef, pork, venison, wild boar, horse, lamb and mutton) in Tokyo (Japan) from 2010 to 2019. Furthermore, the resistance mechanism of erythromycin (EM)-resistant strains was analysed. C. jejuni had a highly positive rate in domestic chicken meat (53.4%, 334/626 samples), domestic chicken offal (49.3%, 34/69 samples), and domestic beef offal (28.3%, 47/166 samples), while C. coli had a high positivity rate in domestic pork offal (31.7%, 44/139 samples). The positive rate of C. jejuni was significantly higher in offal than that in meat in domestic beef, while the positive rate of C. coli was significantly higher in offal than that in meat in domestic beef and domestic pork (p<0.05). In the isolates, 1.0% (6/631 strains) of C. jejuni and 36.2% (55/152 strains) of C. coli were EM resistant, with 41.5% (262/631 strains) of C. jejuni and 65.1% (99/152 strains) of C. coli being ciprofloxacin resistant. A2075G mutation of the 23S rRNA gene was confirmed in all EM-resistant strains.

The maximum growth rate (μ_max) of Bacillus cereus was estimated using a non-destructive isothermal calorimetric method, and a growth prediction model was constructed based on the measurement results. SCD medium and mashed potato were inoculated with serial-diluted inoculum of B. cereus. Heat generation curves were determined using an isothermal calorimeter at 35, 25, and 15℃. The μ_max was determined from the relationship between the increase in B. cereus cell number and incubation time, which was detected through the heat generation of the B. cereus biological process. Moreover, the growth prediction model was constructed using Ratkowsky's square-root model. The results of the growth prediction model based on the data of the calorimetric and conventional culture methods for SCD were expressed as √μ^Cal_max=0.0354 (T-4.9)[R²=0.99] and √μ^CCM_max=0.0335 (T-5.0)[R²=0.99]; a similar equation was provided by both methods. Conversely, the results of the growth prediction model based on the calorimetric method data for mashed potato were given as √μ^Cal_max=0.0390 (T-8.5)[R²=0.99]; the maximum growth rates at 30 and 20℃ were predicted as 0.70 and 0.20 (1/hr), respectively. The maximum growth rates obtained using the conventional culture method were 0.63 and 0.29 (1/hr), respectively, similar to the calorimetric method results. The predictive microbiological analysis using the calorimetric method enabled the rapid provision of a growth prediction equation, and the number of samples could be substantially reduced compared with that for the conventional culture method.

A simultaneous analytical method was developed for the determination of alkyl furans (Furan, 2-methylfuran, 3-methylfuran and 2,5-dimethylfuran) in processed foods by headspace-GC-MS. Single-laboratory validation data of furan, 2-methylfuran, 3-methylfuran and 2,5-dimethylfuran showed good precision and accuracy. The mean recoveries ranged from 92 to 116%, the intermediate precision (RSDi) ranged from 0.9 to 12.9%. The level of LOQ ranged from 0.5 to 1.2 μg/kg (coffee), from 3.5 to 4.1 μg/kg (soy sauce), from 0.4 to 1.3 μg/kg (other foods: clear apple juice, infant formula and baby food), respectively. This method has the sensitivity to detect low levels of furan and alkyl furans contaminated in various foods and is thus applicable to surveillance for risk management in food safety.

The official specifications for food additives from natural sources list the species according to their scientific and Japanese names, thereby providing a unique identifier for the species. This helps to prevent the use of nonprescribed species, which might cause unexpected or unintended health hazards. However, there are cases in which the names of the source species listed in the official specifications differ from the accepted scientific names based on the latest taxonomic research. In this paper, we argue that it is more important to define scientific and Japanese names with an emphasis on traceability in order to control the range of food additive ingredients in a rational and sustainable manner. Therefore, we proposed a method for ensuring traceability as well as a specific notation procedure for scientific and Japanese names. Using this method, we examined the source species for three food additives. In some cases, the range of sources species expanded with the change in scientific names. Ensuring traceability is extremely important, but it is also necessary to confirm whether unexpected species are included when names are changed.

Migrants found in migration solutions obtained from commercially available polyethylene products that may contain food were studied and analysed via liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-QTOF) for non-target screening and LC-MS/MS for quantifying 14 substances in migration solutions. Furthermore, an analytical approach based on the retention gap was developed for accurate separation techniques using LC-MS/MS. Irganox 1076 was detected at a maximum of 1.5 mg/kg, which was 1/4 of the Specific Migration Limit in the EU, in nine commercially available plastic bags tested. This is in accordance with European Regulation No 10/2011/EU. Furthermore, migration of Erucamide and Irgafos 168-oxide was confirmed.

This study developed a method that simultaneously detected 283 pesticide residues in brown rice using GC-MS/MS and LC-MS/MS. In this method, we examined the desirable amount of sodium chloride required for salting out and the SPE cartridge required for clean-up. Pesticide residues from the sample were extracted with acetonitrile using a homogenizer and mixed with salts including anhydrous magnesium, two types of citrate, and sodium chloride. The sample solution of the acetonitrile layer was cleaned up using the GCB/NH₂ (200 mg/200 mg, 6 mL) SPE cartridge. The determination method was validated using two concentrations (0.01 and 0.1 μg/g) of 283 pesticides based on the validation guideline of the Ministry of Health, Labor and Welfare in Japan. Of the 283 pesticides, 250 were detected satisfactorily. In addition, 59 brown rice samples sold in Tokyo were surveyed using the same method. Out of 44 samples, 12 pesticide residues below MRLs were detected. Therefore, this developed method is useful for the simultaneous determination of pesticide residues in brown rice.