Trichothecenes food contamination

Lethality due to ingestion of food contaminated by trichothecenes has been reported in horses (Rodricks and Eppley, 1974), cattle (Hsu et al, 1972), and humans (Joffe, 1974). General clinical signs include emesis, food refusal and weight loss, dermal effects, and immune suppression with secondary infection. Clinical signs are dependent on the specific trichothecene involved, the dose, species, route of exposure, as well as the nature of the exposure. Spontaneous and experimental exposures may give somewhat different results, as can exposure to field contaminated materials, when compared to purified toxin. In the case of field contamination or experimental use of crude extracts, multiple mycotoxins, both known and unknown, may be present at the same time. 

The paucity of positive evidence of the presence of trichothecenes (5 positive environmental and 20 positive biomedical samples) has been used to challenge the belief that biological warfare attacks occurred, since only 10% of samples were positive. However, 32% of samples from victims were positive, a value too high for natural causes (eg, food contamination) to be used as an explanation, since 98% of controls in nonattack areas of Thailand were negative.17 The 2% of samples that were positive could represent either a nonspecific result or low-prevalence food contamination. The paucity and type of control samples have also been questioned. 

Group 2 includes some 80 sesquiterpene trichothecenes, which are particularly associated with fungi belonging to the group Fusarium. Fusarium species are widely known both as plant pathogens and contaminants of stored foods snch as maize. Trichothecenes are strong inhibitors of protein synthesis in mammalian cells. There have been many incidents of poisoning of farm animals cansed by contamination of their food by these componnds. 

In the first part of this chapter, we deal with insecticides including miticides and nematocides, which include very useful compounds such as avermectins and milbemycins, produced by bacteria and fungi. We list out microbial insecticides of importance and review the works mainly on the mode of action and biosynthesis of each metabolite. In the next part, major mycotoxins are listed and recent topics on them, especially on their biosynthesis, are described. Since contamination of two major mycotoxin groups, aflatoxins (AFs) and trichothecenes, in food and feed is a worldwide problem, they are treated in detail in the last part of this chapter. Recent studies on their biosynthesis, regulatory mechanism for their production, and inhibitors of their production are described. 

The mycotoxins with the greatest potential risk to human and animal health as food and feed contaminants are AFs, trichothecenes, fiimonisins, zearalenone, ochratoxin A, and ergot alkaloids.109 Other mycotoxins such as cyclopiazonic acid, sterigmatocystin, gliotoxin, citrinin, penitrems, patulin, fusarin C, penicillic acid, and PR... 

Type D trichothecene mycotoxins consist of Varrucarins and Roridins. Many surveys clarified that all 12, 13-epoxytricho-thecenes possess a potent inhibitory activity on protein and DNA syntheses in eukaryotes, and also possess acute enteritis in man and farm animal health thus, the trichothecene mycotox are one of the important toxicants in man and farm animal health. T-2 toxin was found naturally contaminated in cereals, grains, food and feedstuffs. 

Trichothecene Mycotoxins. Only one class of easily produced, membrane-damaging toxins, the trichothecene mycotoxins, is dermally active. Therefore, they must be considered by standards different from those for all other toxins. Trichothecenes can cause skin lesions and systemic illness without being inhaled and absorbed through the respiratory system. Skin exposure and ingestion of contaminated food are the two likely routes of exposure of soldiers oral intoxication is unlikely in modern, well-trained armies. Nanogram quantities per square centimeter of skin cause irritation, and microgram quantities cause necrosis. If the eye is exposed, microgram doses can cause irreversible injury to the cornea. 

The red mold disease of wheat and barley in Japan is prevalent in the region that faces the Pacific Ocean.4 Toxic trichothecenes, including nivalenol, deoxynivalenol, and monoacetyl-nivalenol (fusarenon-X) from Fusarium nivale, can be isolated from moldy grains. In the suburbs of Tokyo, an illness similar to red mold disease was described in an outbreak of a food-borne disease, as a result of the consumption of Fusarium-infected rice.35 Ingestion of moldy grains that are contaminated with trichothecenes has been associated with mycotoxicosis in domestic farm animals.4... 

In Southeast Asia during the 1970s, symptoms began within minutes after an exploding munition (air-to-surface rocket, aerial bomb, cylinder) caused a yellow, oily, droplet mist to fall on individuals within 100 m of the explosion site. The falling droplet rain was inhaled, swallowed, and collected on skin and clothing contaminated the terrain and food and water supply and caused humans and animals to become acutely ill and to die after a variable period.7 Massive cutaneous contact was prevalent when the sources of exposure were sprays or coarse mists that were used deliberately to contaminate humans and the environment. Although the suspected trichothecene mycotoxin attacks in Southeast Asia would have involved multiple routes of exposure, we can postulate that the skin would have been the major site for deposition of a aerosol spray or coarse mist. 

Trichothecenes constitute a mycotoxin family produced by fungal spiecies from several genera, notably Fusarium, Stachybotrys, Myrothecium, Trichothecium, Trichoderma, Cylindrocarpon, Verticimonosporium, Acremonium, and Phomopsis. Most of the trichothecenes that have been isolated and characterized chemically are from Fusarium species that grow in the field and are distributed worldwide, representing the important pathogens of grains and other food and feed plants. Trichothecenes ap>p)ear as natural contaminants in cereal grains such as wheat, barley, oat, maize, rice, and derived products, such as bread, malt and beer (Scott, 1989). 

Determination of trichothecenes in duplicate diets of young children by capillary gas chromatography with mass spectrometric detection. Food Additives and Contaminants, Vol. 22, No. 1, (January 2005), 48-55, ISSN 0265-203X. 

Lancova, K., Hajslova, J., Kostelanska, M., Kohoutkova, J., Nedelnik, J., Moravcova, H., et al. (2008). Fate of trichothecene mycotoxins during processing milling and baking. Food Additives and Contaminants, 25, 650-659. 

Valle-Algarra, R M., Mateo, E. M., Medina, A., Mateo, R, Gimeno-Adelantado, J. V., limenez, M. (2009). Changes in ochratoxin A and type B trichothecenes contained in wheat flour during dough fermentation and bread baking processes Food Additives Contaminants Part A, 26, 896-906. 

GC/FTIR data have also contributed to the structure elucidation of other compounds of biological origin, such as mycotoxins, which are formed by fungal activity in food products under specific environmental conditions of moisture, temperature, and host. Trichothecene mycotoxins, secondary fungal metabolites produced by species of mold, are a natural contaminant of feedstuffs and food. Because they can be toxic to humans and animals, their detection is important. Sehat et al., utilized GC/MI-FTIR and GC/MS to analyze grains for these contaminants. 

In summary, in depth-exploration of the concept of modifying active sites of trichothecenes both in vitro and in vivo to prevent them from interacting with living cells will not only contribute to our understanding of basic mechanisms of trichothe-cene toxicity at the molecular level, but also should lead to the discovery of new ways to treat contaminated foods and people and to the development of new prophylactic and therapeutic compounds. 

Erom SCOOP data [11], food and food raw materials were shown to be contaminated by trichothecenes (DON, NIV, FX, T-2, and HT2 toxin, T-2 triol, diacetox-yscirpenol, neosolaniol, and verrucarol). 

In recent years the need for more information about the type A trichothecenes has been emphasised, not only with regard to their toxicity (this is greater than that of deoxynivalenol), but also due to the increasing trend of incidence in European cereals. Mycotoxins T-2 and HT-2 (a product of T-2 deacetylation) are found mainly in oats, where their amounts may be up to 1000 p.g/kg, but the annual variabUity of contamination is considerable. The only way to reduce the level of type A trichothecenes in foods and feeds containing oats is the removal of bran from grains, as bran may contain 75 90% of the total amount of these mycotoxins. 

---