Food Safety – The Official Journal of Food Safety Commission of Japan is a peer-reviewed open-access electronic online journal of English published quarterly by the FSCJ. The journal will feature four types of articles: Original Articles, short communications, reviews, and risk assessments conducted by FSCJ.

Scope of the journal
The aim of the publication of Food Safety is to gather and disseminate scientific and technological information in the field of food safety on human health, and thereby facilitate the development of science and technology for risk assessments of foods. The journal publishes original articles, short communications, and reviews covering broad areas of food safety related to the risk assessment of foods as well as risk assessments conducted by FSCJ. Papers dealing with the following areas are particularly welcome: (1) pathogenicity or toxicity of biological, physical, or chemical agents concerning food safety; (2) occurrence of biological, physical, or chemical agents in the food chain with emphasis on food safety; (3) epidemiology or control of food-borne illnesses; and (4) safety evaluation of novel foods including nanomaterials, genetically modified organisms, etc. In addition to these areas, papers on the methodology of risk assessments concerning food safety are encouraged.

Disclaimer
The publication of original articles, short communications and reviews in Food Safety does not mean that the FSCJ condones, endorses, approves, or recommends the use of any products, services, materials, methodology, or policies stated therein. Conclusions and opinions in these articles are those of the individual authors only and do not reflect the policies or view of the FSCJ.

Editor in Chief        Susumu Kumagai (FSCJ)
Associate Editors         Katsue Ishii (FSCJ), Kiyoko Kamiyasuhira (FSCJ), Kunitoshi Mitsumori (FSCJ), Masatsune Murata (FSCJ), Hiroshi Satoh (FSCJ), Yasushi Yamazoe (FSCJ)

Editorial Board        G. Endo (Osaka City University Medical School, Japan), R. Hasegawa (Pharmaceuticals and Medical Devices Agency, Japan), T. Hayakawa (Kinki University, Japan), A. Hirose (National Institute of Health Sciences, Japan), K. Imaida (KagawaUniversity, Japan), H. Kamada (University of Tsukuba, Japan), H. Karaki (Kurashiki University of Science and the Arts, Japan), A.-K. Lundebye (National Institute of Nutrition and Seafood Research, Norway), A. Martin (European Food Safety Authority, Italy), S. Miyazaki (National Institute of Animal Health, japan), H. Mizusawa (Tokyo Medical and Dental University, Japan), M. Naya (BioSafety Research Center, Japan), A. Nishikawa (National Institute of Health Sciences, Japan), T. Nohmi (National Institute of Biomedical Innovation, Japan), K. Ogawa (National Institute of Health Sciences, Japan), H. Ozaki (University of Tokyo, Japan), T. Sakai (Azabu University, Japan), J. Sawada (Pharmaceuticals and Medical Devices Agency, Japan), T. Sekizaki (University of Tokyo, Japan), M. Shimizu (University of Tokyo, Japan), K. Shinagawa (Iwate University, Japan), V. Silano (Medical School, II University of Rome, Italy), Y. Sugita-Konishi (Azabu University, Japan), H. Tsubone (University of Tokyo, Japan), S. Tsuda (Iwate Institute of Environmental Health Sciences, Japan), T. Umemura (National Institute of Health Sciences, Japan), H. Verhagen (National Institute for Public Health and the Environment, The Netherlands), J. Yamate (Osaka Prefecture University, Japan), T. Yoshizawa (Ehime University, Japan).

Editorial Office
Chief Staff       Hideki Hongo (FSCJ)
Staff        Ryusuke Matsuoka (FSCJ), Ayako Kabamoto (FSCJ)
For further information        Yuka Takeuchi (FSCJ), E-mail: fs-journal@cao.go.jp

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From Editor-in-Chief

    Since ancient times, enormous efforts have been devoted to supplying sufficient foods, providing safe foods, and preventing food-borne illnesses. In recent years, such efforts have been directed particularly toward improvement of food supply through innovation and development of agricultural chemicals and food additives, food manufacturing and processing techniques, and food distribution systems. In parallel with the development of science and technology related to the food supply, systems and methods for securing food safety have also progressed markedly in the past decades.

    Nevertheless, recent changes in the environment and circumstances surrounding the food supply have continuously raised concerns about food safety. Global warming is anticipated to cause environmental changes, accompanied by changes in distribution of pathogenic and toxigenic microorganisms, and impairment of crop, livestock and fisheries yields, consequently to cause an increase in health risks through more frequent intake of marine toxins, mycotoxins, food-borne pathogens and other hazardous agents. The growth and expansion of the trade and distribution of food, including industrially produced and processed foods, are anticipated to cause large outbreaks of food poisoning and food-borne infections. Novel foods and foods produced by newly developed techniques may also raise concerns for food safety. In view of this situation surrounding the food supply, it is more important than ever to develop the science and technology that focuses on food safety.

    Science and technology for food safety involve a large number of research fields of different disciplines, and the research outcomes have been disseminated over a wide range of scientific journals devoted to microbiology, biochemistry, toxicology, and epidemiology, and also agricultural, environmental, and public health science. However, to achieve further development of science and technology for food safety, it is necessary to construct a data and knowledge bank in which research outcomes are gathered and available for anyone requiring them. Taking into account the need for such a bank, we have decided to launch a peer-reviewed open-access electronic online journal in English named Food Safety - The Official Journal of the Food Safety Commission of Japan.

    The journal publishes original articles, short communications, and reviews covering broad areas of food safety related to the risk assessment of foods as well as risk assessments conducted by the Food Safety Commission of Japan. Papers dealing with the following areas are particularly welcome: (1) pathogenicity or toxicity of biological, physical, and chemical agents concerning food safety; (2) occurrence of biological, physical, and chemical agents in the food chain with emphasis on food safety; (3) epidemiology or control of food-borne illnesses; and (4) safety evaluation of novel foods, including, among many others, nano-materials and genetically modified organisms. We hope that this new journal will be successful in improving the levels of science and technology for food safety, and that it will contribute to the growth of an integrated research field specifically focusing on food safety.


Susumu Kumagai
Editor-in-Chief

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In the current carcinogenicity assessment, the threshold is a major issue for genotoxic carcinogens. Carcinogenicity is usually assessed in combination with genotoxicity data. The current assessment methodology is based on the hypothesis that non-genotoxic carcinogens have thresholds but genotoxic carcinogens do not. However, it remains unclear in most cases as to how much the detected genotoxic potential is actually associated with the carcinogenicity at an organ level. To clarify this critical issue, in vivo genotoxicity has been investigated in transgenic rodents carrying reporter genes, which can simultaneously detect both genotoxicity and carcinogenicity on each organ basis. Studies of a number of genotoxic carcinogens have revealed good correlations between in vivo genotoxicity and carcinogenicity. However, some discordant results have been also found in some cases. Besides experimentally observed values of genotoxicity, MOA or statistics might be taken into account for biological or practical threshold. Then, statistical or mathematical evaluation can provide values of BMDL or MOE even for strictly defined genotoxic carcinogens. Another major issue is concerning extrapolation of animal data for human risk. For this purpose, WOE approaches based on MOA may be extremely useful. Experiments using transgenic rodents such as p53, nrf2 or CAR knockout mice might be helpful to elucidate the mechanisms of carcinogenicity. The other issues concern the development of screening or alternative methods. In the future, in silico and in vitro approaches will be powerful tools for screening genotoxic and carcinogenic potentials of a number of chemicals/agents.

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Deoxynivalenol (DON), a trichothecene mycotoxin, was characterized together with nivalenol (NIV) from naturally infected wheat and barley grains of the 1970 epidemic in Kagawa^**, Japan. DON, 3-acetyl-DON (3-ADON) and 3,15-diacetyl-DON (3,15-DADON) were identified as metabolites of Fusarium roseum No.117 (=F. graminearum ATCC 28114), a toxic isolate from the cereals of the 1970 epidemic, and their toxicological properties in animals, including acute toxicity, emetic activity, and in vivo de-epoxydation metabolism into DOM-1 (deepoxy-DON), were elucidated. Natural co-occurrence of DON and NIV in the domestic cereals was found to be common not only in southern Japan but also in other regions, and the geographic difference in the occurrence of both toxins in Japan was elucidated. In terms of mycotoxigenicity, F. graminearum strains isolated from crop fields were divided into two types: DON- and NIV-producers, and DON-producer was further subdivided into two subtypes, 3-ADON- and 15-acetyl-DON-producers by biotransformation experiment of 3,15-DADON as a precursor. The geographic differences in the incidence of these producers in Japan were observed. Correlation between the incidence of the toxin producers and the occurrence of DON and NIV were investigated by field trials. For screening NIV alone or in combination with DON in cereals, specific monoclonal antibodies were produced, and practical ELISA kits were successfully developed. In relation to our previous findings, current advances in the molecular phylogenetic analysis of mycotoxigenic F. graminearum, the molecular genetics of trichothecene biosynthesis, among others, were briefly reviewed.

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The Food Safety Commission (FSC) was founded in 2003 to conduct the risk assessment of chemicals in food and food products and also residues of agricultural chemicals. Genotoxicity assessment is one component of the overall risk assessment process. Historically, genotoxicity assessment has been limited mainly to qualitative hazard identification. We are proposing a strategy for when the chemical is classified as a genotoxic carcinogen and the acceptable daily intake (ADI) cannot be set because a worldwide consensus has not been obtained on the existence of threshold for DNA direct-acting genotoxicity. To evaluate the mechanism(s) of carcinogenicity, it is important to make judgment whether genotoxicity, especially genotoxicity/mutagenicity resulting from direct reaction with DNA, is a key event or not in the carcinogenic process. Here, we focus on the residues of agricultural chemicals and discuss the strategy of how to evaluate and interpret genotoxicity, and provide guidance that we can use at the site of assessment. This paper presents the authors’ personal opinion and it does not necessarily represent the official opinion of the FSC. There are four independent expert working groups in the Expert Committee for evaluation of agricultural chemicals and the authors hope this paper will help to make evaluation fair and transparent across the working groups. Of course, other strategies to evaluate genotoxicity of food and food related chemicals, including residues of agricultural chemicals may also exist, and they should also be appreciated. The goal is scientifically sound, transparent, and fair evaluation and interpretation of genotoxicity, as an integral part of the risk assessment.

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Infectious prion diseases include Kuru and its variant, Creutzfeldt-Jakob disease, in humans, scrapie in sheep, and bovine spongiform encephalopathy in cattle. In these diseases, the pathogenic prion protein (PrP^Sc) enters the host through the gastrointestinal tract and migrates to the central nervous system, where PrP^Sc induces characteristic pathological changes. The mechanisms underlying this intercellular transfer are not fully understood. After oral administration, PrP^Sc withstands the digestive process and may be incorporated by microfold cells (M cells) or villous columnar epithelial cells in the intestine. Based on Western Blot with specific markers, liquid chromatography, and morphological analysis, the cellular prion protein (PrP^C) and PrP^Sc in the cells are associated with exosomes, membranous vesicles that are secreted upon fusion of multivesicular endosomes with the plasma membranes. Exosomes may play a role in PrP transportation through intestinal epithelium. Cells may exploit the nature of endosome-derived exosomes to communicate with each other in normal and pathological situations, providing for a novel route of cell-to-cell communication and therefore of pathogen transmission in the intestinal epithelium. In addition, since most bovine spongiform encephalopathy cases were exposed to the agent in the first six months of life, developmental alteration of the intestinal defense and immune system may also be involved in the susceptibility to infection.

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Fumonisins are mycotoxins produced predominantly by Fusarium verticillioides and F. proliferatum. They contaminate maize and maize-based foods throughout the world. Fumonisin B₁ is the most common. It causes species-specific toxicities in laboratory and farm animals including liver and kidney cancer in rodents. Inhibition of ceramide synthase and disruption of sphingolipid metabolism is the non-genotoxic mechanism underlying its toxicological and carcinogenic effects. The extent to which fumonisin B₁ or other fumonisins impact human health remains poorly understood although epidemiological and experimental evidence implicate them as a risk factor for esophageal cancer and neural tube defects in populations consuming large amounts of contaminated maize-based foods. Selected toxicological investigations providing evidence for the above and serving as a basis for applied studies to better understand the extent of human exposure and potential risk are reviewed. The latter includes the use of kidney toxicity in rats as a bioassay showing that alkaline cooking (nixtamalization, the traditional method for making masa and tortillas) and extrusion effectively reduce the toxicity of fumonisin-contaminated maize and the development of robust exposure biomarkers for use in epidemiological studies. Future initiatives to better understand the relationship between fumonisins and human health should emphasize validation of biomarkers, such as urinary fumonisin B₁ concentration, as well as comparative studies to determine which animal models are most relevant to humans.

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The Food Safety Commission of Japan (FSCJ) was asked by the Ministry of Health, Labour and Welfare to assess the risks of chemical substances related to the revision of the standards and criteria for ‘beverages.’ Since fluorine is one of the substances, the risk assessment on fluorine and fluoride was conducted. The data used in the assessment include those from: acute toxicity tests in mice and rats, subacute toxicity tests in mice, rats, rabbits, dogs and pigs, chronic toxicity and carcinogenicity tests in mice, rats and rabbits, neurotoxicity tests in mice and rats, immunotoxicity tests in mice, rats and rabbits, reproductive and developmental toxicity tests in mice and rats, genotoxicity tests, and epidemiological studies and others. Although fluorine has been considered to be an essential element, clear evidence has not been presented. Moreover, its daily minimum requirement has not been established. Epidemiological studies to examine the carcinogenicity of fluoride in drinking water have been conducted, but failed to provide clear evidence of carcinogenicity in humans. Carcinogenicity has not been clearly shown in laboratory animals, either. Fluoride has been reported to be weakly genotoxic in in vitro studies using cultured mammalian cells. It is, however, reported that in vivo DNA damage tests have not indicated genotoxicity. Taken together, it was considered that fluorine has no genotoxicity relevant to human health. Hence, it was concluded that it is appropriate to specify a tolerable daily intake (TDI) of fluorine in terms of non-carcinogenic toxicity. Based on an epidemiological study of 5,800 children from 12 to 14 years old in the United States, a concentration of 1.0 ppm at which effect was not observed, was taken as a base. Given that the body weight of a child is 20 kg and the amount of water that a child drinks per day is 1 L, no-observed-adverse-effect-level (NOAEL) was calculated to be 0.05 mg/kg body weight per day. Since this value was that obtained from the study of susceptible population, it was considered that this value could be taken as TDI without applying uncertainty factors. As a conclusion, FSCJ specified the TDI of fluorine to be 0.05 mg/kg body weight per day.

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