An unidentified foodborne disease associated with the consumption of raw fresh fish was noticed from 1999 in the West of Japan. In 2010, a novel multivalvulid parasite, Kudoa septempunctata (Myxozoa: Myxosporea) was discovered as being the causative agent of this disease and the Ministry of Health, Labour and Welfare of Japan (MHLW) named this disease “Kudoa food poisoning”. Kudoa septempunctata is a myxosporean with 6–7 polar capsules and shell valves in a spore. The life-cycle of K. septempunctata has not been elucidated yet. However, it probably involves an alternative invertebrate host such as polychaetes without direct transmission between fish. An epidemiological study elucidated that the main symptoms of “Kudoa food poisoning” are transient vomiting, diarrhea, abdominal pain and vomiting due to gastrointestinal mucosal disruption, most of which could be recovered within 24 h. The threshold for the onset of symptoms is estimated at about 7.2 × 107K. septempunctata spores per person based on an epidemiological calculation of a large-scale outbreak that occurred at Ehime prefecture. In a toxicological study, oral administration of 1 × 107 spore/g live K. septempunctata induced the acute accumulation of fluid in the gut of suckling mice and vomiting in house musk shrews (Suncus murinus). K. septempunctata decreased transepithelial resistance in a cultured human intestinal cell monolayer, resulting in a rapid increase of permeability. These pathogenic actions of viable Kudoa spores elicit symptoms in human patients. Regarding analytical methods, PCR amplification of species-specific genes and microscopic observation of characteristic spores are the best methods of choice for characterizing this parasite. To prevent the disease, heating at 95 °C for 10 min or freezing at −80 °C overnight is effective while a recent study demonstrated that liquid freezing is a more practical method. Fundamentally, the biological study of K. septempunctata including its life-cycle, alternative and invertebrate hosts is necessary for eradicating them. Realistically, monitoring of domestic flounder in farm and imported one in the quarantine should be useful. From the available literature, K. septempunctata appears to be a unique parasitic agent that induces foodborne diseases by invading the human intestinal mucosa but does not persist long enough in the tissue for further growth, eliciting a temporal increase in mucosal permeability. Further investigations are needed to elucidate the interactions between this myxosporean parasite and human tissue.
In this study, we developed a semi-quantitative risk mapping tool to assess the risk of damage to human health resulting from infection by meat-borne parasites. The developed method is based on the R-Map methodology, which is widely used in industrial settings to assess hazards in Japan. The risk of damage to health due to parasite infection was determined by two main criteria: the annual number of patients and the extent of damage to health. The former criterion was subdivided into four categories and the latter was evaluated based on severity of illness and period required to obtain a cure (hereafter, period to cure). The four categories for extent of damage to health were calculated by multiplying the scores assigned for severity of illness by the period to cure. Each parasite could then be mapped to this 4 × 4 matrix depending on the annual number of patients and the extent of damage to health. Three risk-level zones were then superimposed on the matrix to determine the priority of implementing risk management measures. In this way, the risk to human health associated with each parasite and the priority associated with implementing control measures could be visualized. Toxoplasma gondii infection in human immunodeficiency virus-infected patients and newborn babies was mapped to the unacceptable risk zone due to the severity of the disease in these patients. Emerging parasites, such as Sarcocystis fayeri, Kudoa septempunctata and Taenia asiatica, were mapped to the zone in which the risk of parasitic infections should be reduced by implementing urgent control measures, since doing so would prevent any further increase in infections. The risk assessment tool developed in this study can be employed to evaluate previous and potential risks of parasite infection and is useful for assessing the efficacy of risk control measures.
Seaweeds are a source of arsenosugars (AsSug). AsSug are mainly metabolized to dimethylarsenic species, but their relative health risks have not yet been fully evaluated. Therefore, it is essential to assess the risk of AsSug intake. Although AsSug are water-soluble arsenics, the extraction efficiency of arsenic compounds from wakame seaweed specimens (Undaria pinnatifida) ranges only between 4 and 49%. To develop a high recovery-rate extraction method without altering the chemical structure of the arsenic compounds, we examined the efficacy of a combined enzymatic treatment and methanol (MeOH) extraction method. After treatment with cellulase and alginate lyase and extraction with 100% MeOH, we extracted 88.8% of the arsenic compounds in wakame without arsenic species alteration. Four arsenic peaks were detected using high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS), two of which were identified as 3-[5′-deoxy-5′-(dimethylarsinoyl)-β-ribofuranosyloxy]-2-hydroxypropylene glycol and 3-[5′-deoxy-5′-(dimethylarsinoyl)-β-ribofuranosyloxy]-2-hydroxypropyl-2,3-hydroxypropyl phosphate by using HPLC-electrospray ionization-quadrupole–time-of-flight mass spectrometry (HPLC-ESI-Q-TOF-MS). Further, the HPLC-ESI-Q-TOF-MS analyses suggested that, of the remaining two peaks, one corresponded to arsenic-hydrocarbon 388 (C21H45OAs) and arsenic-phospholipid 1012 (C49H94O14PAs). Thus, our method can be used to extract arsenic compounds from brown algae with strong cell walls.
The Food Safety Commission of Japan (FSCJ) conducted a risk assessment on antimicrobial-resistant bacteria resulting from the use of veterinary medicinal products, of which the active ingredient is fluoroquinolone, for the use of chicken growth. The hazards identified are Salmonella spp., Campylobacter spp. and Escherichia coli which acquired antimicrobial resistance as a consequence of using the fluoroquinolone antimicrobial agents in chicken. FSCJ considers that the following possibilities cannot be neglected: 1) selection of hazards as a result of the use of fluoroquinolone antimicrobials in chicken; 2) human exposure to the hazards through consumption of chicken-derived foods; 3) loss or reduction of the efficacy of antimicrobial treatment of human diseases. Particularly regarding Campylobacter spp., the emergence of antimicrobial resistance was a great concern in the release assessment. The food contamination with Campylobacter spp. including the hazard was also the great concern in the exposure assessment. The risk for each hazard was, however, judged to be “Medium” as a result of the overall estimation of the risk. Regarding antimicrobial-resistant bacteria, detailed scientific findings and information are not sufficiently available at this point, and an internationally accepted methodology for the risk assessment has not yet been established. Therefore, it is necessary to keep up with the latest scientific findings and information including the development of discussion in international organizations.
The Food Safety Commission of Japan (FSCJ) conducted a risk assessment of 2,3-diethylpyrazine (CAS No.15707–24-1) based on results from various studies. This additive, 2,3-diethylpyrazine, has no apparent toxicity relevant to human health based on the results of studies including the genotoxicity and repeated dose toxicity. The additive (flavoring) was categorized into Structural class II of the report of “Working group on safety assessment method of flavorings” (November 4, 2003) (classification criteria of Structural classes I, II and III are based on Cramer et al. (1978), which are similar to those of Joint FAO/WHO Expert Committee on Food Additives (JECFA)). The safety margin exceeds 1,000 which is regarded as the appropriate safety margin for a 90-day repeated dose toxicity study. The predicted amount of intake (1–2 µg/person/day) is also lower than the acceptable daily intake of Structural class II (540 µg/person/day). FSCJ concluded that 2,3-diethylpyrazine, an additive (flavoring), has no concern relevant to human health when it is used for the purpose of flavoring food.