A recent incident involving contamination of Chinese-made frozen gyouza dumplings with agricultural chemicals has raised many issues. These include not only food safety, but also problem areas of the Food Sanitation Law, dependence on frozen processed foods, Japan’s low rate of food self-sufficiency, and international relations with China. The present paper gives an outline of the incident and discusses related issues, including problem areas of the Food Sanitation Law and problems with analytical methods, from the perspective of a scientist engaged in analysis operations related to the incident.
In recent years, computer hardware has become more powerful and more popularized. Software for specialized data processing, such as statistical analysis, is also becoming common as a result of the open-source movement. These changes have made some novel statistical techniques more accessible. Typical examples are the randomized test and the Monte Carlo method, which are now used frequently by some skilled researchers. Among average users, however, the use of such techniques is not common. In the present paper, I present these techniques and the R codes necessary to estimate parameter distribution with the Monte Carlo method.
To evaluate the safety of L-cystine and L-theanine in humans, we carried out a clinical trial of high-dose and long-term administration in the form of a controlled randomized double-blind study. Forty healthy subjects, 20 males and 20 females, were given three sachets of food containing L-cystine and L-theanine or three sachets of placebo once a day for four weeks. The dosage of L-cystine and L-theanine was three times the dosage previously shown to exert significant enhancing effect on the immune response to influenza vaccine inoculation. High-dose administration was found to cause no significant clinical changes, no abnormal findings in clinical laboratory data, and no adverse effects. Although some statistically significant changes were observed in laboratory data, all were clinically insignificant variations within the normal range. It was therefore concluded that L-cystine and L-theanine are safe when administered for four weeks at daily doses of up to 2,100mg of L-cystine and 840mg of L-theanine.