Microbial risk assessment in food safety is a valuable tool to reduce the risks of infection by pathogens. The dose-response relation is aimed to establish the relationship between the dose of a pathogen that populations are exposed to and the probability of the adverse health effect by the pathogen. Among many dose–response models ever proposed, the exponential and beta-Poisson models have been internationally applied, but the decision on which model is selected between them solely depends on the goodness of fit to specific data sets. On the other hands, the log-logistic model, one of the alternative models, has been little studied on the dose–response relation. In the present study, thus, the application of the log-logistic model to dose–response relation was studied with hypothetical and experimental data sets of infection (or death), comparing to the above two models. Here the experimental data sets were for pathogenic organisms such as pathogenic Escherichia coli, Listeria monocytogenes, and Cryptosporidium pavrum. Consequently, this model successfully fit to those data sets in comparison to the two models. These results suggested that log-logistic model would have the potential to apply to the dose–response relation, similar to the exponential and beta-Poisson models.
In Japan, the import quarantine procedure for dairy products was newly introduced in November 2017. The treatment such as 15 sec heating at 72℃ is required for virus inactivation when importing milk or dairy products from the area which is not free from foot and mouth disease. Moreover, the heating history of imported items is also inspected as import quality procedures. The IDF 63 method is known as one of the methods to confirm the heating history of milk by checking the alkaline phosphatase (ALP) activity. However, this procedure is complicated for daily quarantine inspection. Therefore, we attempted the ALP activity measurement based on the amount of fluorescent substance produced by the enzymatic reaction. Milk and dairy products derived from cow, sheep, and goat were tested after various heat treatment conditions. The ALP of heat-treated milk and dairy products derived from these species above were confirmed to be inactivated under substantially the same heat treatment for 15 sec at 72℃. The measurement method established in this study is simpler, faster, and requires smaller amount of sample compared to other methods. Additionally, the method was also applicable to confirm the heating history of various dairy products by making them into suspension.
We studied the efficiency of methylation for analyzing brominated vegetable oil (BVO). In this report, we investigated whether 1H-NMR is an applicable method for assessing the efficiency of methylation to analyze BVO. 1H-NMR sufficiently calculated the efficiency of methylation using each integral and the numbers of protons derived from the methyl group, which is characteristic in products, and the methine group, which is characteristic in unreacted substances. Additionally, the efficiency of methylation calculated via 1H-NMR was in good agreement with changes in the peak area of BVO fatty acid methyl esters (BVOFAMEs) after various heating times obtained from GC-FID analysis. Therefore, 1H-NMR is applicable for calculating the efficiency of methylation to analyze BVO.
Benchmark dose (BMD) method have been used in the toxicological assessment of chemical substances so that the point of departure can be derived, as an alternative to the use of no observable adverse effect level (NOAEL), and the method is often applied to the incidence data of histopathological findings in the toxicity studies. In the present study, the BMD method was applied to various patterns of incidence data derived from some toxicity studies as case studies, and the validity of each application was discussed. Five independent applications including toxicity studies of madder color or semicarbazide hydrochloride were prepared and model averaging over the three models with the lowest three AIC (Akaike information criteria) values (MA-3), a recently proposed model averaging method, was employed. The series of case studies indicated, for the better application of the BMD method to histopathological findings, the following points:(i) If there are incidence data with severity grading of pathologically significant lesions, we must discuss whether the BMD method should be applied to the total incidence data or the incidence data above certain grade with or without data aggregation.(ii) If a lesion of interest had higher toxicological significance rather than the secondary lesions with higher severity, the BMD method should be applied to the incidence data of the lesion of interest.(iii) If it is highly necessary to apply the BMD method to obtained incidence data without toxicological and statistical validity, toxicological pathologists are advised to review individual datasets of histopathology and associated data, and provide new incidence data of comprehensive findings (diagnostic name) such as hepatocellular injury or nephropathy, if possible. In all cases, toxicological significance and mechanism of a lesion of interest need to be considered in light of the dose-dependence. In view of both toxicology and statistics, sufficient discussions must be made on the validity of applying BMD method and its estimate.
This study determined the configuration of the isomers of tadalafil, nortadalafil, and homotadalafil in dietary supplements. The products purchased over the Internet studied included a honey product and a tablet, which contained tadalafil, and a candy, which contained nortadalafil and homotadalafil. Each of the pharmaceutical ingredients isolated from the products was measured with circular dichroism (CD).As a result, the CD spectrum of each isolated pharmaceutical ingredient was found to align with the standard CD spectrum of the 6R,12aR isomer, confirmed that each isolated tadalafil or tadalafil analogue included in a 6R,12aR isomer. According to a report, among the stereoisomers of tadalafil, the 6R,12aR isomers have the most potent inhibitory activities of phosphodiesterase-type-5. From the report, the potential strength of the inhibitory activity of the 6R,12aR isomers of nortadalafil and homotadalafil was suggested. Therefore, it seemed that the 6R,12aR isomer often used in the product.