RESUMO:Os fungos entomopatogênicos são importantes agentes de controle biológico em todo o mundo e têm sido objeto de intensa pesquisa por mais de 100 anos, infectando artrópodes na natureza e podendo ocorrer em níveis enzoóticos ou epizoóticos em suas populações de hospedeiros. O seu mecanismo de infecção envolve a fixação do esporo à cutícula do inseto, seguido da germinação, penetração da cutícula e disseminação interna no inseto. As linhagens dos fungos entomopatogênicos estão concentradas nas ordens: Hypocreales (vários gêneros), Onygenales (gênero Ascosphaera), Entomophthorales e Neozygitales (Entomophthoromycota). PALAVRAS-CHAVE: taxonomia; toxinas; enzimas; hospedeiros.ABSTRACT: Entomopathogenic fungi are important biological control agents throughout the world, have been the subject of intensive research for more than 100 years, and can occur at epizootic or enzootic levels in their host populations. Their mode of action against insects involves attaching a spore to the insect cuticle, followed by germination, penetration of the cuticle, and dissemination inside the insect. Strains of entomopathogenic fungi are concentrated in the following orders: Hypocreales (various genera), Onygenales (Ascosphaera genus), Entomophthorales, and Neozygitales (Entomophthoromycota).

Fourier transform infrared is considered a powerful technique for characterizing chemical compositions of complex probes such as microorganisms. It has successfully been applied to fungal identification. In this paper, the current state of identification and characterization of filamentous fungi and yeasts by Fourier transform infrared is reviewed.

Ochratoxin A (OA) is receiving attention world-wide because of the hazard it poses to human health. The aim was to test the distribution of OA in grape juice, pulps of frozen grapes, and national and imported table wine obtained from markets in Rio de Janeiro, Brazil. Analytical methodology using immunoaffinity column for OA extraction and clean-up with a final separation on a reversed-phase (C(18)) column and fluorescence detection in high-performance liquid chromatography showed a detection limit of 21 ng l(-1). The mean recovery was 91% for red wines and 82% for white wines; while the mean recoveries for juices and pulps of frozen grapes were 91.6 and 88%, respectively. Of 64 samples of grape juice and frozen pulps, 25% were positive for OA, being the mean content of 37 ng l(-1) with a maximum concentration of 100 ng l(-1). In wines, the mean concentration detected in 80 samples analysed was 34.4 ng l(-1) with 28.75% of positive samples. Red wines showed the highest percentages and levels of contaminated samples: 38% and 37 ng l(-1), respectively. The white wine contained levels above 26 ng l(-1) in 17.75% of the analysed samples. The levels of contamination detected in red wine sold in Río de Janeiro were not enough to surpass the virtually safe dose established as 5 n g kg(-1) body weight of daily intake.

Poultry feeds are prone to fungal growth and mycotoxin production during processing. The identification of biota with the ability to produce mycotoxins is essential. The aims of this study were (1) to monitor the mycobiota counts at different stages of poultry feed processing; (2) to determine the occurrence of Aspergillus species; (3) to evaluate the natural incidence of aflatoxins and ochratoxin A. The ability of Aspergillus spp. and its teleomorphs isolated here to produce these toxins was also investigated. Samples (144) were collected at random from a factory in Brazil. The occurrence of Aspergillus and Eurotium species was demonstrated on DRBC and DG18 media and the production of aflatoxins and ochratoxin A and their natural incidence were determined by TLC and HPLC methods. A. flavus and E. chevalieri were the most prevalent species isolated. Fungal contamination was not found after the pelleting process, though Aspergillus and Eurotium species were recovered from trough samples. High levels of aflatoxin and ochratoxin A producers were found at all stages of poultry feed processing. Also, high natural contamination with aflatoxins and ochratoxin A was found in the samples. Contact of feed with remainder poultry feed could lead to fungal contamination, so the risk of aflatoxin and/or ochratoxin A contamination of feed must be taken into account.

The intake of mycotoxin-contaminated feeds can lead to nutrient losses and may have adverse effects on animal health and on productivity. The aims of this study were (1) to determine the mycobiota present in poultry feed samples, and (2) to evaluate the natural occurrence of aflatoxin B(1), fumonisin B(1) and zearalenone. Fungal counts were similar between all culture media tested (10(3 )CFU g(-1)). The most frequent genus isolated was Penicillium spp. (41.26%) followed by Aspergillus spp. (33.33%) and Fusarium spp. (20.63%). High precision liquid chromatography was applied to quantify aflatoxin B(1) and fumonisin B(1). Thin layer chromatography was used to determine zearalenone levels. Aflatoxin B(1 )values ranged between 1.2 and 17.5 microg kg(-1). Fumonisin B(1) levels ranged between 1.5 and 5.5 microg g(-1). Zearalenone levels ranged between 0.1 and 7 microg g(-1). The present study shows the simultaneous occurrence of two carcinogenic mycotoxins, aflatoxin B(1) and fumonisin B(1), together with another Fusarium mycotoxin (zearalenone) in feed intended for poultry consumption. Many samples contained AFB(1 )levels near the permissible maximum and it could affect young animals. A synergistic toxic response is possible in animals under simultaneous exposure.

The effects of O 3 concentration, exposure time and grain mass were evaluated on the levels of deoxynivalenol, aflatoxins and total fungal count (TFC) in wheat grains, using a full 2 3 factorial design. Grain samples were contaminated with fungal conidia and spiked with mycotoxins standards and then submitted to ozonation treatments. The most significant reductions obtained for deoxynivalenol and total aflatoxins corresponded to 64.3 and 48.0%, respectively. TFC reduced approximately 3.0 cycles log cfu/g of wheat grain. O 3 concentration and exposure time influenced (P < 0.05) positively the reductions of both mycotoxins and TFC, while the grain mass had a negative effect on both responses. The most significant reduction in TFC and mycotoxin levels was achieved by using 60 mg/L of O 3 for 300 min, with 2 kg samples. Gaseous O 3 can be considered an excellent method for remediation of these contaminants. PRACTICAL APPLICATIONSGaseous ozonation is an interesting nonthermal technology that can be applied to reduce fungal and mycotoxin contamination in wheat grains (Triticum aestivum L.). The O 3 concentration and exposure time positively influence reductions in mycotoxins and fungi count, while grain mass has a negative effect on both variables. Using 60 mg/L of O 3 at 300 min of exposure and 2 kg grain samples (11.3% moisture content) is possible to obtain reductions of 3.0 cycles log cfu/g in total fungal count, 64.3% in DON levels and 48.0% in total aflatoxin levels. Data found in this research should contribute in greater interest of ozonation by the food industry and consequently a wider popularization of ozonized products by consumers.

The aim was to identify the normal mycoflora in wine grapes from Argentina and Brazil. We collected 50 grapes samples from Malbec and Chardonnay varieties in each country during the 1997-98 harvest. Yeasts were a major component of the fungal population, and the most frequent genera of filamentous fungi isolated were: Aspergillus, Penicillium and Botrytis. Other genera identified (in decreasing order) were: Phythophthora, Moniliella, Alternaria and Cladosporium. From grapes, the mean frequency of filamentous fungi ranged from 1.3 x 10(4) to 5.4 x 10(6) CFU g(-1). We isolated 48 Aspergillus niger strains from Argentinian grape, of which eight could produce ochratoxin A. Sixteen of 53 A. niger strains from Brazilian grapes produced ochratoxin A. The results indicate that similar mycobiota were isolated from Argentinian and Brazilian wine grapes and there could be ochratoxin A production in this substrate.

Aims:  The objective of this study was to determine the ochratoxin (OT) and aflatoxin (AF) production by three strains of Aspergillus spp. under different water activities, temperature and incubation time on barley rootlets (BR). Methods and Results:  Aspergillus ochraceus and Aspergillus flavus were able to produce mycotoxins on BR. Aspergillus ochraceus produced ochratoxin A (OTA) at 0·80 water activity (aw), at 25 and 30°C as optimal environmental conditions. The OTA production varies at different incubation days depending on aw. Aflatoxin B1 (AFB1) accumulation was obtained at 25°C, at 0·80 and 0·95 aw, after 14 and 21 incubation days respectively. Temperature was a critical factor influencing OTA and AFB1 production. Conclusions:  This study demonstrates that BR support OTA and AFB1 production at relatively low water activity (0·80 aw) and high temperatures (25–30°C). Significance and Impact of the Study:  The study of ecophysiological parameters and their interactions would determine the prevailing environmental factors, which enhance the mycotoxin production on BR used as animal feed.