|Yamamoto, Shigeki -|
Submitted to: Food Additives & Contaminants
Publication Type: Proceedings
Publication Acceptance Date: June 4, 2013
Publication Date: July 17, 2013
Citation: Yamamoto, S., Voss, K.A. 2013. Risk control and food safety. Food Additives & Contaminants: Part A. 30(8):1349-1350. DOI: 10.1080/19440049.2013.812440. Interpretive Summary: The 11th International Symposium on Toxic Microorganisms of the Joint Panel on Toxic Microorganisms, US-Japan Cooperative Program on Development and Utilization of Natural Resources (UJNR), was held March 4-9, 2012 in Tokyo, Japan. The theme of this meeting was "Risk Control and Food Safety." A broad, interdisciplinary approach is needed to control health risks to consumers that are associated with pathogens, algal toxins (phycotoxins) and fungal toxins (mycotoxins) found in foods, thus the need for such an international group of scientists. A series of multidisciplinary research reports and reviews were presented that highlighted recent progress in efforts to more effectively control risks associated with selected food borne contaminants is presented in this special issue. These include development of more sensitive analytical methods for monitoring phycotoxins and mycotoxins in foods; improving methods for identification of microorganisms involved in food poisoning outbreaks; surveillance of exposure assessment of mycotoxins in foods; and basic and applied toxicological studies for assessing the risks associated with mycotoxins in foods. These approaches contribute to better understanding and improved control of food borne risks to consumers.
Technical Abstract: The 11th International Symposium on Toxic Microorganisms of the Joint Panel on Toxic Microorganisms, US-Japan Cooperative Program on Development and Utilization of Natural Resources (UJNR), was held March 4-9, 2012 in Tokyo, Japan. Having the theme "Risk Control and Food Safety," it was the most recent in a series of UJNR international symposia directed toward reducing risks to consumers posed by food-borne pathogens, toxigenic microorganisms and their toxins. This selection of symposium presentations includes original research reports and reviews that cover a diverse range of topics and underscore the multidisciplinary approach needed to reduce food-borne health risks. The symposium was broadly divided into sessions on seafood toxins, fungal toxins and pathogenic bacteria. Development of sensitive, robust analytical methods for known and novel toxins remains a priority for assuring the safety of seafood. Watanabe et al. describe novel cleanup and LC-MS/MS procedures that offer improved sensitivity and simultaneous quantitation of 12 saxitoxins produced by the dinoflagellate Alexandrium tamarense and the freshwater cyanobacteria Anabaena circinalis. Palytoxin is a nonprotein marine toxin that is suspected to cause Haff's Disease as well as poisonings associated with consumption of blue humphead parrotfish (Scarus ovifrans) in Japan. The latter supposition has been based largely on the appearance of Haff's disease-like clinical signs in patients however involvement of the toxin has been problematic due to the absence of reliable analytical methods. Suzuki et al. report development of improved LC-MS/MS methodology for palytoxin in Scarus ovifrans tissue and, using this methodology, rule out its involvement in two cases of blue humphead parrotfish poisoning. Kudoa semptempunctata, a mycosporeum parasite, is a pathogen responsible for outbreaks of diarrhea-emesis in consumers of contaminated olive flounder (Paralichthys olivaceus). Little is known about the mechanism(s) involved and, in the third article devoted to seafood contaminants, Ohnishi et al. present in vitro evidence that K. semtempunctata spores are recognized by toll-like receptor 2 (TLR2) in macrophages and the up-regulation of pro-inflammatory cytokines, including NF-KappaB-dependent production of tumor necrosis factor alpha (TNF). Minimizing mycotoxin exposures is a multidisciplinary effort targeting the entire "farm to fork" sequence. This includes improved capability to predict geographical distribution of fungi and mycotoxins in crops under changing climatic conditions. To this end, Watanabe et al. explore the phylogenetic relationships among trichothecene-producing Fusarium species and suggest that some Fusarium species, heretofore considered non-mycotoxigenic, should be reconsidered in regard to their potential to produce trichothecenes and other mycotoxins. Improving host resistance to fungi is a traditional approach for reducing mycotoxins in cereal crops. New techniques and insights for facilitating the identification and exploitation of resistance factors to aflatoxigenic fungi are reviewed by Brown et al. Exposure and risk assessments also play a key role in controlling mycotoxin risks. Sugita-Konishi et al. summarize the findings of a six-year surveillance of Japanese foods for ochratoxin A and fumonisins. Simulated exposures based on the survey results revealed that exposures in Japan are low but also that close monitoring of exposures in infants and small children should be continued. Carryover into meat is another potential source of mycotoxin exposure. Japanese black cattle are suspected to be especially sensitive to lolitrem B, a mycotoxin of Neotyphodium lolii in ryegrass. Shimada et al. have established a no observed adverse effect level for lolitrem B in black cattle fed contaminated ryegrass straw. Further, they conducted a biodistribution study and concluded that exposure to this mycotoxin via consumption of beef from Japanese black cattle would be low. Mycotoxins such as deoxynivalenol and other trichothecenes exist in free and conjugated forms in grain, raising concerns that analytical methods focusing only on "free" mycotoxin might underestimate exposures. Nakagawa et al. discuss the effectiveness of a newly developed LC-Orbitrap MS method for selected type A trichothecene glucosides. Despite improvements in analytical methodology, unknown metabolites, conjugates or degradation products might form during cooking and contribute to toxicity. In vivo bioassay therefore remains a useful tool to evaluated processing methods as demonstrated by Voss and colleagues, who demonstrated that alkaline cooking effectively detoxifies fumonisin-contaminated maize. Disease outbreaks from bacterial pathogens in food remain a serious public health problem. Rapid and accurate identification and characterization of organisms involved is essential to limit the number of individual cases in an outbreak as well as to differentiate between pathogenic and nonpathogenic strains of bacteria. Optical genome mapping and DNA microarray genotyping are methods for bacterial strain subtyping and enhancement of trace back analyses during outbreaks. Elkins et al. review these techniques and, using case studies involving Shiga toxin-producing Escherichia coli and Salmonella enteric serovars as examples, discuss their advantages and limitations for pathogen differentiation. The use of microarray, pulse field gel electrophoresis and other genomic techniques for molecular sub-typing of Listeria monocytogenes is reviewed by Datta et al. It is also important to determine those food types that are vulnerable to contamination and the handling/storage conditions that most favor bacterial growth. In a second article devoted to L. monocytogenes, Okada et al. tested its growth potential in a selection of refrigerated ready-to-eat foods that are popular in Japan. They determined conditions favoring growth and identified foods that should be considered potential sources of listeriosis. Hara-Kudo et al. report the prevalence of common pathogens including Salmonella, Shiga toxin-producing E. coli O157, Campylobacter jejuni/coli in selected meats, vegetables and seafoods from retail outlets as determined by the National Food Surveillance System in Japan, 1998-2008. Providencia alcalafaciens are enterobacteriacea that on occasion cause diarrhetic illness in consumers. In vitro studies by Asakura and colleagues provide new insight into the pathobiology of this organism which includes LPS-dependent disruption epithelial barrier function and endothelial apoptosis. A comprehensive update covering ongoing initiatives for better controlling the health risks associated with phycotoxins, mycotoxins, and pathogens in foods is beyond the scope of this issue. The articles do however report recent progress in some specific research areas contributing to improved understanding and control of risks to consumers related to these food contaminants. The UJNR panel members thank the organizers, hosts, speakers and all others who contributed to making the 11th International Symposium on Toxic Microorganisms a success. We also thank Food Additives and Contaminants for again making this selection of reports from the event available to scientists and others interested in assuring food safety.