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ABSTRACT: Soybean (Glycine max L.), the main source of protein throughout the world, is used both as a food and a feedstuff. Currently, limited information about the occurrence of Fusarium species and mycotoxins in soybean grain and by-products is available. The aims of the present study were: (1) to identify toxigenic Fusarium species associated with soybean during crop reproductive stages; (2) to determine the occurrence of deoxynivalenol (DON) and nivalenol (NIV) in soybean seeds; (3) to determine the genotype and chemotype of selected Fg complex strains using molecular and chemical analysis, respectively; and (4) to characterize the strains using AFLP(s) markers. One soybean field located at Córdoba Province, Argentina, was monitored and samples of soybean tissue were harvested at three reproductive stages: flowering (R2), full seed (R6) and full maturity (R8). A total of 389 Fusarium strains F. equiseti (40%) was the most frequently species recovered followed by F. semitectum (27%) and F. graminearum (Fg) (11%). From the 40 soybean samples analysed, only two presented detectable DON levels. Based on DON occurrence on soybean seeds at ripening stages, the toxigenic ability of Fg complex strains isolated from soybean seeds, pods and flowers were analysed. The trichothecene genotype was determined by a multiplex PCR using primers based on Tri3, Tri5 and Tri7 toxin genes and then the chemotype was verified by chemical analysis. Most Fg complex strains showed 15-ADON genotype and five strains presented a DON/NIV; these also produced both toxins under in vitro culture. Neither the NIV nor the 3-ADON genotypes were detected among the members of the population evaluated. All the 15-ADON genotype strains were characterized as F. graminearum sensu stricto (lineage 7), while the strains presented a DON/NIV genotype were characterized as F. meridionale (lineage 2). The present study contributes new information on the occurrence of Fusarium species and trichothecenes toxins on soybean at the pre-harvest stages. Also, this is the first report on the chemotype, genotype and lineages among Fg complex isolated from soybean.
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment 01/2011; 29(2):293-303.
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ABSTRACT: The aims of this work were to identify potential sources of Aspergillus parasiticus inoculum and to evaluate the sclerotial and toxigenic profiles of this species from the peanut agroecosystem in Argentina. Likewise, the genetic diversity of A. parasiticus population was analysed using vegetative compatibility group (VCG) analysis.
The A. parasiticus strains were isolated from soil, debris and peanut seeds in Córdoba Province, Argentina. A. parasiticus was recovered from the three sources analysed. Only 11 of 185 A. parasiticus isolates (5.9%) did not produce aflatoxins, while 57% produced sclerotia. Twenty-four VCG were identified from 63 isolates. The VCG diversity index for A. parasiticus, expressed as the number of groups divided by the total number of isolates, was 0.31. In general, there were significant differences among VCG in aflatoxin production.
The presence of aflatoxigenic strains of A. parasiticus in the three substrates suggests that they may be an important source of aflatoxin in Argentina's peanut agroecosystem. The A. parasiticus population shows a low genetic diversity.
The present study showed data on inoculum distribution, aflatoxin and sclerotia production and genetic diversity in an A. parasiticus population isolated from the peanut agroecosystem in Argentina.
Letters in Applied Microbiology 07/2006; 42(6):560-6. · 1.62 Impact Factor
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ABSTRACT: Aims: To examine the effect of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), trihydroxybutyrophenone and propylparaben (PP) (at concentrations of 1–20 mmol l−1) on growth of and fumonisin production by Argentinian strains of Fusarium verticillioides and F. proliferatum.Methods and Results: Studies on lag phases prior to growth, relative growth rates and fumonisin concentrations were carried out in vitro in relation to water activity (0·995–0·93 aw) and temperature (18 and 25°C) on a maize meal agar. Overall, PP was the antioxidant which was most effective at inhibiting strains of both species. The lag phase prior to growth and growth rates were significantly decreased by PP and BHA at 10 and 20 mmol l−1, regardless of the temperature or aw level tested. Total fumonisin production was higher at 0·98 aw and decreased by about 45–50% at 0·995 and 0·95 aw. Overall, BHT only inhibited fumonisin production at 0·95 aw at 10 and 20 mmol l−1, while BHA was effective at most aw levels tested at 10 and 20 mmol l−1. Propylparaben completely inhibited fumonisin production by both F. verticillioides and F. proliferatum at > 1 mmol l−1, regardless of the temperature or aw level. Small interstrain differences in the levels of inhibition by the antioxidants were observed for three F. verticillioides and four F. proliferatum strains at 0·995, 0·98 and 0·95 aw. Propylparaben and BHA completely inhibited the growth of both species at the concentrations evaluated, regardless of the aw level.Conclusions: Two antioxidants show promise for the control of growth of and fumonisin production by these species over a wide range of environmental conditionsSignificance and Impact of the Study: Potential exists for using such food-grade preservatives for prevention of mycotoxigenic fungi and their toxins entering the food chain.
Journal of Applied Microbiology 03/2002; 92(4):624 - 632. · 2.34 Impact Factor
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ABSTRACT: To examine the effect of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), trihydroxybutyrophenone and propylparaben (PP) (at concentrations of 1-20 mmol l(-1)) on growth of and fumonisin production by Argentinian strains of Fusarium verticillioides and F. proliferatum.
Studies on lag phases prior to growth, relative growth rates and fumonisin concentrations were carried out in vitro in relation to water activity (0.995-0.93 a(w)) and temperature (18 and 25 degrees C) on a maize meal agar. Overall, PP was the antioxidant which was most effective at inhibiting strains of both species. The lag phase prior to growth and growth rates were significantly decreased by PP and BHA at 10 and 20 mmol l(-1), regardless of the temperature or aw level tested. Total fumonisin production was higher at 0.98 a(w) and decreased by about 45-50% at 0.995 and 0.95 a(w). Overall, BHT only inhibited fumonisin production at 0.95 aw at 10 and 20 mmol l(-1), while BHA was effective at most a(w) levels tested at 10 and 20 mmol l(-1). Propylparaben completely inhibited fumonisin production by both F. verticillioides and F. proliferatum at > 1 mmol l(-1), regardless of the temperature or a(w) level. Small interstrain differences in the levels of inhibition by the antioxidants were observed for three F. verticillioides and four F. proliferatum strains at 0.995, 0.98 and 0.95 a(w). Propylparaben and BHA completely inhibited the growth of both species at the concentrations evaluated, regardless of the a(w) level.
Two antioxidants show promise for the control of growth of and fumonisin production by these species over a wide range of environmental conditions.
Potential exists for using such food-grade preservatives for prevention of mycotoxigenic fungi and their toxins entering the food chain.
Journal of Applied Microbiology 01/2002; 92(4):624-32. · 2.34 Impact Factor
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ABSTRACT: A study has been carried out in Argentina on samples of corn genotypes from a breeding station as well as in commercially available corn meal. All samples were analyzed for fungal infection and aflatoxin B1. Mycological analysis of corn genotypes showed the presence of three principal genera of filamentous fungi Fusarium (100%), Penicillium (67%) and Aspergillus (60%). In the genus Fusarium three species were identified, F. moniliforme (42%), F. nygamai (56%) and F. proliferatum (1.8%). Eight species of Penicillium were identified, the predominant species isolated were P. minioluteum, P. funiculosum and P. variabile. In the genus ranked third in isolation frequency, two species were identified, A. flavus and A. parasiticus, the percentage of infection was 78% and 21%, respectively. Only one corn genotype was contaminated with aflatoxin B1 at a level of 5 ppb. The corn meal samples showed great differences in fungal contamination, the values ranging from 1 x 10(1) to 7 x 10(5) cfu g-1. Fusarium (68%), Aspergillus (35%) and Penicillium (21%) were the most frequent genera isolated. Among the genus, Aspergillus, A. parasiticus (38%) was the most frequent species isolated. All the samples of corn meal were negative to aflatoxin B1. These results indicate a low degree of human exposure to aflatoxins in Argentina through the ingestion of maize or corn meal.
Mycopathologia 02/1999; 147(1):37-41. · 1.65 Impact Factor
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ABSTRACT: Alternaria cultures (87 isolates of Alternaria alternata, four of A. tenuissima, two of A. radicina, and three of Alternaria state of Pleospora infectoria respectively, from maize) were screened to determine their ability to produce alternariol (AOH) and alternariol monomethyl ether (AME) on maize and rice. Only 28 A. alternata stains had toxigenic capacity. When maize was used as substrate 21 of 28 isolates produced AOH and AME, and 23 of 28 strains produced AOH and 22 of 28 produced AME when rice was used. The level of AOH produced by the isolates ranged from 0.3 to 2.1 mg/kg on maize and from 0.4 to 9.9 mg/kg on rice. The AME production by the stains ranged between 0.3 and 3.3 mg/kg both on maize and on rice. These results could indicate a low probability of AOH and AME occurring naturally on maize in Argentina.
Food Additives and Contaminants 01/1998; 15(1):56-60. · 2.13 Impact Factor
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ABSTRACT: During the 1993 harvest period there was a high incidence of Fusarium head blight in wheat in Argentina. Fusarium species that produce trichothecenes in wheat have been reported in several countries including Argentina. Several studies have shown that F. graminerarum and deoxynivalenol (DON) were the main contaminants detected in wheat and by-products in Argentina. The objective of this study was to evaluate the occurrence of Fusarium spp. and DON contamination in wheat from Córdoba, Argentina during the 1993/94 harvest season. F. graminearum was the main Fusarium species isolated. From 40 samples analysed, 80% showed DON contamination. The levels of DON found ranged between 300 and 4500 micrograms/kg. There was good correlation between F. graminearum and DON contamination. Only five samples showed levels of DON higher than those established in the guidelines in Canada and the USA for food and feedstuffs.
Food Additives and Contaminants 02/1997; 14(1):11-4. · 2.13 Impact Factor
