WHAT IS FUNGI?
Fungi (Myces) are plant-similar microorganisms, some of them are large sized (as mushrooms) and the others are microscopic, therefore they are poly-or-mono-cellular. Some of the fungi are useful for man, since they could be eaten or used in producing drugs, dairy products, bread…. etc., and used in fungal biocontrol. Yet, the others are harmful to man, animals, and plants, since they cause diseases (mycoses) and/or intoxications (mycotoxicoses). Therefore, fungi are responsible for crops damage (25% of the yearly production), whether in the field, during transportation, and/or during storage. Toxic fungi can also invade various feed - and foodstuffs and hence affect agricultural animals (Abdelhamid and Saleh, 1996) and humans (Abdelhamid et al., 1999). Moreover, these toxigenic fungi occur also in and/or on moist houses, libraries, air conditioners, feed mills, dust, air, insects, temples, banknotes, and computer disks and compact disks (Abdelhamid, 1998, 1999-b, and 2000-b).
WHAT IS MYCOTOXIN?
It is a fungal toxin, i.e. it is a secondary toxic - metabolite which produced from a toxigenic fungus. Any mycotoxin could be produced from many fungal species, and any fungal strain can produce many mycotoxins. Therefore, any moldy sample may contain numerous fungal genera and species (multi-infection), hence and consequently it may be contaminated with different mycotoxins.
For instance, zearalenone (F-2) is produced by Fusarium roseum, F. tricinctum, F. oxysporum, and F. moniliforme. Also, diacetoxyscirpenol (DAS) producing fungi are F. equiseti, F. sambucinum, F. tricinctum, F. scirpi, F. solani, F. rigidiusculum, F. culmorum and F. avenaceum. On the other hand, A. ochracious produces aflatoxins, ochratoxins, penicillic acid, cycalonic acid, viomllin….. etc., and A. flavus produces, aflatrime, aflatoxins, aspergillic acid, aspertoxin, cyclopiazonic acid, kojic acid, penetrimes, rubratoxins, sterigmatocystin, tremorgns etc. So, when one mycotoxin is detected, a man should suspect that others are also present in a contaminated feed (Abdelhamid, 2000-b). However, the story of mycotoxins is very new compared with the old known story of fungi. It began with the detection of ergot, trichothecenes, aflatoxins…. and recently fumonisins. Nowadays, more than one thousand different chemically identified mycotoxins are isolated. They are of low molecular weights. Some of them act with each other synergistically as fumonisin-B1 and aflatoxin-B1, ochratoxin-A and aflatoxin, T2 toxin and aflatoxin. Mycotoxins cause a wide variety of adverse clinical signs depending on the nature and concentration of mycotoxins present, duration of exposure, the animal species, its age and nutritional and health status at the time of exposure to contaminated feed (Horvath, 1998).