MESOPHILIC AND THERMOPHILIC FILAMENTOUS FUNGI ISOLATED FROM PROCESSED OATS ( Avena sativa L . ) IN · BRASIL ( Hongos filamentosos mesofílicos y termofílicos aislados de avena procesada ( Avena sativa L . ) en Brasil )

Con la finalidad de verificar la presencia de hongosfilamentososmesófilos y termófilos, se analizaron muestras de ffi'ena procesada envasada en: contenedores metálicos, caja de cartón y bolsas plásticas, ya sea en forma de escamas finas o gruesas, así como en harinas. Las muestrasfueron procesadas mediante tres diluciones (1:10, 1: 1 00, 1: 1 00) Y sembradas en placas de Pe tri en Agar Sabouraud + eAF, incubandose a 3 temperaturas: ambiente 28± 2°C, 45°C Y 50°e. Se aislaron un total de 48 taxa de hongos filamentosos, representados en 14 géneros. Aspergillusy Penicillium ,fueron los géneros más ji"ecuentes, seguidos por Cladosporium, Rlrizopus, Syncephalastrum, Curvularia, Acremonium, Nigrospora, Paecilomyces, Tritiraclrium, Sporotlrrix, Oidiodendron y un representante de 10sAplrylloplrorales. A las temperatura de 45°e y 50°C, se aislaron Aspergillusfumigatus, A. duricaulis, Rlrizopus microsporus, R. oryzae, siendo A.fumigatus el que presentó un mayor número de aislamientos


INTRODUCTION
Oat (Avena saliva L.), has been worldwide produced for human and animal consumption, due to its great nutritive value and other digestive qualities (14).
The microbiota responsible for causing the wheat deterioration in food, specially in oats, corn, barley,

SUMMARY
In order to determine the occurrence of mesophilic and thermophilic filamentous fungi on processed oats, samples of powered, thin and thick oat flakes, kept in cans, can/board boxes, and plastic bags were ana/ysed.For each sample, 3 dilutions were prepared: 1: JO, 1: 100, 1: 1 000 and they were placed on Pe tri dishes with Sabouraud agar plus antibiotic and incubated at 3 temperatures, 28± 2 0 e, 45 0 C. and 500 e.
wheat, and rye, is greatIy influenced by internal factors connected directly with the food, such as nutritive value, pH, humidity, o:\."ygen reduction potential, inhibitory compound, as well as by external factors like temperature, time of storage, relative humidity contained in the grain, insects, mechanical damage, and the presence and concentration of gases (12, 17).Among the contaminating microorganisms of food, fungi are responsible for the deterioration (2,4).The aflatoxin, secondary metabolite produced by fungi , is also encountered in many food , such as soybean, com, wheat, I)'e, oats, rice, among others (15).On lhe other hand, the occurrence of thermophilic and thermotolerant fungi in fooci has been the objective of taxonomic studies beca use of the great damage caused to processed' foods (8).
In Brazil studies focused on the occurrence o[ fungi in grains and processed oats were poor.Consequently to support this, it \Vas suggested tocan'Y out research ",ork on com, barley, wheat and rice in grain according by Stenwing & Liven (32) and Sauer et al (30) methodology.
The objeclives o[lhe present work ,,"ere: the isolalion and identification of filamenlous fungi on processed oals, to delermine the presence ofmesophilic and lhermophilic fungi, and the quality -quantity analysis of these fungi detected, considering the melhods of processing and packing of the oaL

MA TERIAL AND METHODS
The following processing and packaging o[ oats were utilized: thin and thick flaked oats in cardboard boxes and cans; powered oat in cardboard boxes: unrefined oat bran in cans and in plastic bags.
Samples were obtained in many supermarkets and selected those unopened and wilhin the valid date [or consumption.The thin and lhick flaked oals in cardboard boxes and cans were oblained from lwo industries, lhe powered oal in cardboard boxes was obtained from three industries, and lhe unrefined oal bran in cans and plaslic bags were oblained onl)' from one industry.Thirteen samples ,,¡ere tested.The following culture media were used for isolation and identification ofthe fungi: Sabouraud agar plus yeasl exlracl and CAF ( 0, 100 gil), Pota lo dexlrose agar, Czapek agar, Oat agar, and Malt exlract agar (20).The Warcup melhod (33), modified isolalion lechnique based on diluilion melhod was used lo isolale fungi in one gram of each oal.Sample was aseptically weighled and diluted in 10 mi of distilled slerilized suspension.From lhis diluled solulion with concenlration of 1: 100 and 1: 1 OOOwere prepared.A 0.2 mi sample of each dilution \Vas plaled in lriplicale on Pelri dishes in Sabouraud-yeasl extracl agar + CAF, and homogenize equally.Cultures were gro",n at three temperalures: in a 28 "C ( ± 2 "C) incubator room, or in a clectric incubalor at -l5 "c, and 50 "c, for an up lo se\'en da)' periodo After 72 hours processed fungal colonies "ere counled and di fferenl iso lates were tra nsferred lo speci fic cull u re media used for lhe corresponding groups of fungi.
Each fungi isolates at 45°C and 50 0 e were inoculated on polalo dextrose agar and incubated at 45°e and 50 0 e for seven days.
The species isolated were storaged in lhe Micotheca URM, of lhe Mycology Deparlmenl of the Biological Center of Science (CCB), at lhe Federal University oflhe Pernambuco (UFPE).

RESUL TS AND DISCUSSrON
In the analysis of 13  A tolal of 30 colonies of termophilic and thermotolerant fungi in lhree genera and five species.represenled lhe 10.64% of lolal [ungi isolated, where A. fumigatus \Vas the mosl frecuenl (Table 2).
Witliin the isolaled species.there are SOJ11e of them bearing potential abililies to produce micotoxins in food, mainly A. flavus and A.parasiticus.The [onner \Vas isolated just once "hile the lalter (6% of the isolates), a   closely related species, is also a greather producer of micotoxis, and the most strains producingB an G aflatoxin, two compounds which are toxic for animals.Aflatoxin B 1 is certainly acutely toxic for humans, and responsible for liver necrosis following chronic exposure, and mainly involved in human liver cancer, perhaps synergistically with hepatitis B virus (9,10,21).With regard to processed oats, the first step involves the improvement of the phase of sanitation, that consists in the removal of foreign material s, followed by a slow heating designed to reduce the moisture content of the grain until it remains at about 6% and to avoid fungal development.
The large number offungi found in the various forms of packing, can be explained by the procedures 'connected to the last stage of the process of production.Johnson &Peterson (18), state that oats do not receive an efficient sterilization, since they are exposed only to fast boiling and heating, and the flaked material is later ground into flour and then packed.This form of processing is easily susceptible to fungal containination.
In relation to the type of packaging, it was observed that there was more contamination in cardboard boxes than in cans, which indica tes that the material utilized for packaging mayenable an increase of moisture and temperature enough to allow later germination of propagules existing ina latent stage.Since Aspergillus and Penicillium, classified as "storage fungi"occurred frequently in the samples of processed oats, it is possible to suggest that these were acquired during the storage period ofthe grain .This fact was observed by Christensen (5) who concluded that fungar propagules on the seed coat of cereals can remain domlant inside the grain and develop when proper conditions arise.Most ofthe taxa isolated in this work were also observed by other researchers, in grains of oats, wheat, com, and barley (3,24,30,32).Sorne of tlie fungi isolated from these natural substrates are thermotolerant and thermophilic.Physiological and biochemical factors influence their thermophilic capacity allowing them to grow and reproduce effectively at high temperatures (7,8).Thermophilic species detected in this work are commonly isolated from soil (3,22), but were also found in wheat, barley, hay and bean leaves (1,23,31).