Food Hygiene and Safety Science最新文献

Assuming food poisoning caused by toxic plants, an LC-TOF-MS-based method for the rapid and simultaneous analysis of 16 plant toxins was established. After adding water-methanol (1 : 9) and n-hexane, the samples were homogenized and extracted, and then subjected to centrifugal separation. Without any purification procedures, LC-TOF-MS measurements were performed, and qualitative and quantitative analyses using monoisotopic ion [M+H]+ (m/z) were conducted. The addition-recovery test using curry showed that qualitative analysis was possible under a setting with a retention time of ±0.2 minutes or less and mass accuracy of 5 ppm or lower and that quantitative analysis was possible with a recovery rate of 68-142% and a repeatability of 1.4-10.1%. Furthermore, measurements of the amount of plant toxins in the boiled plants and broths of cooked toxic plants demonstrated the transfer of plant toxins to broths. These suggest that in the event of food poisoning, broths may be used as an analysis sample, even when plants are not available.

Ciguatera fish poisoning (CFP), known as a seafood-borne disease, is caused by consumption of fish contaminated with ciguatoxins in tropical and subtropical sea. The ciguatera fishes, Variola louti, Lutjanus monostigma and L. bohar have an absolute majority in the Ryukyu Archipelago, southwestern Japan. We developed the cluster analysis of phylogenetic tree by using mitochondrial (mt) DNA 16S rRNA sequences of V. louti, L. monostigma and L. bohar and differentiate them from morphologically similar species (L. fulviflamma, L. russellii, L. argentimaculatus, Plectropomus leopardus and V. albimarginata) in our previous study. The fish were acquired from the coastal waters of the Ryukyu Archipelago, and a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) marker of the mtDNA 16S rRNA region was used, employing the restriction enzymes BmgT120 I, Dde I, and SnaB I, to identify the fish species responsible for CFP. These results showed that a PCR-RFLP marker can be obtained more easily than a nucleotide sequence.

An outbreak of Salmonella Stanley in the United States associated with dried wood ear mushrooms imported from China prompted us to conduct serotyping of Salmonella isolated from dried wood ear mushrooms in voluntary testing, and quantitative test for Salmonella along with enumeration of hygienic indicator bacteria in positive samples in order to evaluate the risk of Salmonella outbreak from dried wood ear mushrooms. The major serovars of Salmonella isolates obtained from 20 samples were as follows: O3,10 group-London (n=3) and Weltevreden (n=5) etc, totaling 9 strains; O4 serogroup-Saintpaul (n=2), Stanley (n=1), Typhimurium (including monophasic variant; n=3), totaling 6 strains. O7 serogroup (Potsdam) and O8 serogroup (Newport) were one strain each. Qualitative and quantitative tests for Salmonella were conducted on 10 samples with remaining amounts. As a result, one sample was 220 MPN/g, six samples were<0.6 MPN/g, and three samples were negative for Salmonella per 25 g. The mean aerobic bacterial counts and coliforms in these samples were 7.8 and 6.1 log₁₀ CFU/g, respectively. Furthermore, qualitative test for Salmonella and enumeration of hygienic indicator bacteria were conducted on dried wood ear mushroom products (33 domestic and 30 imported products) retailed in Japan. No samples showed positive for Salmonella per 25 g, and the mean aerobic bacterial counts and coliforms were approximately 2 log₁₀ CFU/g lower than those in the 10 samples where Salmonella was isolated during voluntary testing. While no Salmonella was detected in domestically retailed wood ear mushrooms products, the serovars associated with foodborne diseases were isolated from voluntary testing samples. It indicates that potential for consumption of Salmonella contaminated wood ear mushrooms, which is at risk of causing food poisoning.

In the Japanese official detection method for unauthorized genetically modified (GM) papayas, one of two types of real-time PCR reagents with DNA polymerase (TaqMan Gene Master Mix [TaqMan Gene] or FastGene QPCR Probe Mastermix w/ROX [FastGene]) is primarily used for measurement. In 2022, we conducted a laboratory performance study on the unauthorized GM papaya line PRSV-YK, and the results revealed that high threshold cycle (Cq) values for the PRSV-YK detection test were obtained using TaqMan Gene with the 7500 Fast & 7500 Real-Time PCR System (ABI7500) and QuantStudio 12K Flex (QS12K), indicating the possibility of false negatives. The possibility of similar problems with all unauthorized GM papaya lines detection tests needs to be evaluated. In this study, we performed detection tests on unauthorized GM papaya lines (PRSV-YK, PRSV-SC, and PRSV-HN), the cauliflower mosaic virus 35S promotor (CaM), and a papaya positive control (Chy), and examined how the limits of detection (LOD) for each test are affected by two types of DNA polymerases (TaqMan Gene and FastGene) and three types of real-time PCR instruments (ABI7500, QS12K, and LightCycler 480 Instrument II [LC480]). In the PRSV-YK and PRSV-SC detection tests using ABI7500 and QS12K, measurement with TaqMan Gene showed a higher LOD than FastGene. In this case, an exponential amplification curve was confirmed on the amplification plot; however, the amplification curve did not cross the ΔRn threshold line and the correct Cq value was not obtained with a threshold line=0.2. The other tests (PRSV-HN, CaM, and Chy with ABI7500 and QS12K, and all detection tests with LC480) showed no important differences in the LOD for each test using either DNA polymerase. Therefore, when performing PRSV-YK and PRSV-SC detection tests with the ABI7500 or QS12K, FastGene should be used to avoid false negatives for foods containing GM papaya lines PRSV-YK and PRSV-SC at low mixing levels.

From October 2020 to February 2021, a total of 95 retail chicken meat products from 39 retail meat shops in Tokyo Metropolis and Kanagawa Prefecture, Japan, were collected and examined for the prevalence of Salmonella to assess public health implications. If a sample tested positive for Salmonella, a quantitative analysis was performed using the three-tube most probable number (MPN) method. Of 95 retail chicken meat products, Salmonella was isolated from 30 samples (31.6%). The levels of Salmonella contamination ranged from <0.3 to 4.3 MPN/g. The most frequent level was <0.3 MPN/g (63.3%). Of the 33 Salmonella strains isolated, four serotypes were identified: S. Schwarzengrund (60.6%), S. Infantis (24.2%), S. Agona (12.1%), and S. Manhattan (3.0%). Multilocus sequence typing (MLST) analysis classified most S. Schwarzengrund isolates into sequence type (ST) 241, the same ST found in chicken meat in Japan, except for one isolate. Of the 33 Salmonella isolates, 29 (87.9%) were antibiotic resistant. Twenty-six isolates (78.8%) showed multidrug resistance to two or more antibiotics. Therefore, these results indicate that retail chicken meat products in Japan are an important source of Salmonella infection in humans and that Salmonella contamination in retail chicken products seems to originate from chicken meat.

Recently, an instrumental analysis using LC-MS/MS has been developed and validated for paralytic shellfish toxins (PSTs) and tetrodotoxin (TTX) in bivalve molluscs in Japanese domestic and overseas. The method for 11 PSTs and TTX in scallops was validated in accordance with a previous report and CODEX-STAN. The samples were prepared by adding the standard mixture of PSTs and TTX to scallop (Patinopecten yessoensis) homogenates, extracted with 1% acetic acid and then cleaned up using an ENVI-Carb (250 mg/3 mL) cartridge. A single analyst extracted and analyzed in two samples per day on five successive days. As result of the validation, 11 PSTs were found falling within all the guideline criteria (the trueness, repeatability, within laboratory reproducibility, LOD, LOQ) in the tests using matrix-matched calibration or solvent calibration.However, the trueness of TTX was low value in the test using solvent standard. It would be due to the matrix effects at the LC-MS/MS analysis. The slope of the calibration curve at the matrix-matched standards of mussel was about the same as the slope at the solvent standards. Therefore, it is necessary to choose the most appropriate matrix depending on shellfish.

Multilayer laminated films are widely used as food packaging materials. The substances contained in these films have the potential to migrate into food in contact, but the actual situation is unknown. In this study, we first determined the contents of 24 elements in 42 food laminate bags by ICP-OES and ICP-MS. As a result, 17 elements (Na, Mg, Al, P, Ca, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Sr, Sn, Sb and Pb) were detected, whereas seven (K, Ni, Ge, As, Ag, Cd and Ba) were below the limits of quantification (LOQs). The detected elements were probably derived from such as impurities in the aluminum layer, metal catalysts, pigments and adhesives. Next, migration tests were performed in 14 of these samples using two types of food simulants (distilled water and 4% acetic acid). The maximum migration levels of Sb, Sn, and Al were 0.11, 5.5 and 74.8 ng/mL, respectively, and the other elements were below the LOQs. It was suggested that Sb and Sn may have migrated from the non-food contact layer.

The level of radioactive cesium in food that is generally consumed in the rehydrated state can be calculated from measurements taken in the dried state using the specific weight change rate set by the Ministry of Health, Labour and Welfare. However, only a few dried foods have a specified weight change rate. Accurate specific weight change rates are critical in determining the compliance of a dried food item with Japanese maximum limits (JMLs) for radioactivity. We investigated the weight change rate of dried to rehydrated kotake mushrooms, which may contain relatively high concentrations of radioactive cesium and whose weight change rate has a large effect on the judgment of JML compliance. The average weight change rate of dried kotake mushrooms was 5.7 (range: 4.2 to 6.9), which was 1.4 times larger than the currently applied weight change rate of 4.0. Since the minimum weight change rate was 4.2 in this study, it was considered that the weight change rate currently applied to dried kotake mushrooms was a reasonable value. Further data is required in order to set specified weight change rates and to evaluate the validity of currently applied weight change rates in dried kotake mushroom.

In this study, a public seminar on risk communication methods was conducted to raise awareness and disseminate accurate knowledge about residual pesticides to consumers. Additionally, surveys on consumer awareness were conducted on the attendees before and after the seminar to evaluate its effectiveness. Responses were obtained from 84 participants. The paired t-test was used to analyze the changes in awareness before and after the seminar. The results showed significant improvements in "trust in the government" and "understanding of residual pesticides." Furthermore, step-wise multiple regression analysis was performed to explore the factors influencing satisfaction with the risk communication seminar, and the item "understanding of the safety of residual pesticides in food" was extracted. Understanding food safety is a crucial concern in daily life for consumers. To enable consumers to have an accurate understanding of food risks and make appropriate judgments, it is essential to continue implementing risk communication and conveying information about food safety and security in the future.

Ciguatera poisoning (CP) is one of the most frequent seafood poisonings across the globe. CP results from the consumption of fish flesh that has accumulated principal toxins known as ciguatoxins (CTXs), and it mainly occurs in tropical and subtropical regions. In Japan, incidents of CP have been reported primarily from Okinawa and Amami Islands in the subtropical area. Meanwhile, there have also been reports from Mainland sporadically. Since the amount of CTXs contained in fish flesh is extremely low, a highly sensitive detection method by LC-MS/MS is required. But the currently reported detection method is applicable only to specific equipment, and many laboratories have difficulty to respond CP. In this study, to prepare for the risk of nationwide CP, we researched a universal analytical method for CTXs based on LC-MS/MS. Using a water/acetonitrile mobile phase supplemented with lithium hydroxide and formic acid gave rise to prominent peaks of the stable [M+Li]+ions. As the [M+Li]+ions did not produce valid product ions even with high collision energy, the [M+Li]+ions of each analog were set for both precursor and product ions ([M+Li]+>[M+Li]+) and monitored under the multiple reaction monitoring (MRM) mode. With the method described above, analyses of nine CTX congeners were carried out. The limit of detection (LOD, S/N>5) and quantitation (LOQ, S/N>10) were estimated as 0.005-0.030 ng/mL and 0.010-0.061 ng/mL, respectively. When the 1 mL of extract solution is prepared from 5 g of the fish tissue, the LOD and LOQ will be at 0.001-0.006 μg/kg and 0.002-0.012 μg/kg, respectively. This result indicates that we could detect the required level of 0.175 μg/kg CTX1B equivalent in fish flesh which is recommended for safe consumption in Japan. This method is considered to be a universal analytical method without depending on the specific equipment. Thus it could contribute to improving the CP investigations in nationwide laboratories.