Growth and aflatoxin production of an Italian strain of Aspergillus flavus: influence of ecological factors and nutritional substrates

2011 ◽  
Vol 4 (4) ◽  
pp. 425-432 ◽  
Author(s):  
P. Giorni ◽  
N. Magan ◽  
A. Pietri ◽  
P. Battilani
Keyword(s):  
Predictive Model ◽  
Aspergillus Flavus ◽  
Growth Rates ◽  
Fungal Growth ◽  
Ecological Factors ◽  
Quantitative Relationship ◽  
Aflatoxin Production ◽  
Optimum Temperature ◽  
Ripening Stages ◽  
Aflatoxin B

The aim of this study was to define quantitative relationships between temperature and water activity (aw), fungal growth and aflatoxin B1 (AFB1) production. A strain of Aspergillus flavus isolated from maize in north Italy, and previously tested and found positive for AFB1 production, was used for these experiments. The optimum temperature for AFB1 production was at 25 °C, slightly lower with respect to results obtained in other countries. 0.83 aw was the limit for growth of this strain of A. flavus after 60 days incubation at the optimum temperature. The solutes used to modify aw, glycerol and NaCl, influenced both growth and secondary metabolite production. Media modified with glycerol resulted in more AFB1 production when compared to the non-ionic solute NaCl added media. Maize based media, prepared with flour obtained from kernels at different ripening stages, only slightly influenced growth rates of A. flavus. The quantitative relationship obtained between fungal growth and AFB1 production in diverse temperature and aw levels were used to develop a valid predictive model for A. flavus presence and AFB1 production in the field.

Control of Aspergillus flavus and aflatoxin production with spices in culture medium and rice

2013 ◽  
Vol 6 (1) ◽  
pp. 43-50 ◽  
Author(s):  
V. Aiko ◽  
A. Mehta
Keyword(s):  
Aspergillus Flavus ◽  
High Performance ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Culture Broth ◽  
Minimum Inhibitory Concentrations ◽  
Food Grains ◽  
Star Anise ◽  
Aflatoxin B ◽  
Layer Chromatography

Cinnamon, cardamom, star anise and clove were studied for their effect on growth of Aspergillus flavus and aflatoxin B1 (AFB1) synthesis. The experiments were carried out in yeast extract sucrose culture broth as well as in rice supplemented with spices. AFB1 produced was analysed qualitatively and quantitatively using thin layer chromatography and high performance liquid chromatography, respectively. At a concentration of 10 mg/ml, cardamom and star anise did not exhibit any antifungal or anti-aflatoxigenic activity in culture broth, whereas cinnamon and clove inhibited A. flavus growth completely. The minimum inhibitory concentrations of cinnamon and clove were 4 and 2 mg/ml, respectively. Concentrations of cinnamon and clove below their minimum inhibitory concentrations showed enhanced fungal growth, while AFB1 synthesis was reduced. Clove inhibited the synthesis of AFB1 significantly up to 99% at concentrations ≥1.0 mg/ml. The spices also inhibited AFB1 synthesis in rice at 5 mg/g, although fungal growth was not inhibited. Clove and cinnamon inhibited AFB1 synthesis significantly up to 99 and 92%, respectively, and star anise and cardamom by 41 and 23%, respectively. The results of this study suggest the use of whole spices rather than their essential oils for controlling fungal and mycotoxin contamination in food grains.

Aflatoxin production by Aspergillus flavus and Aspergillus parasiticus on deoiled ground nyjer seeds

2021 ◽  
Vol 14 (2) ◽  
pp. 213-220
Author(s):  
D. Gizachew ◽  
C.-H. Chang ◽  
B. Szonyi ◽  
W.E. Ting
Keyword(s):  
Water Activity ◽  
Aspergillus Flavus ◽  
Aspergillus Parasiticus ◽  
Animal Feed ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Growth Conditions ◽  
Growth Patterns ◽  
Aflatoxin B ◽  
Similar Growth

Nyjer seeds are oil rich (35-40% oil content) seeds of the plant Guizotia abyssinica, which is closely related to sunflower. They are pressed mechanically for cooking oil in Ethiopia and elsewhere. The remaining deoiled cake, which contains approximately 10% oil is commonly used as animal feed. This study investigated the effect of water activity and temperature on the growth and aflatoxin production of the four main forms of aflatoxin (B1, B2, G1 and G2) by Aspergillus flavus and Aspergillus parasiticus on ground nyjer seed with 10% oil. The ground nyjer seeds were adjusted to different water activity aw levels (0.82, 0.86, 0.90, 0.94 and 0.98 aw) and incubated at 20, 27 and 35 °C, up to 30 days. Our results show that A. flavus and A. parasiticus had similar growth patterns in which the slowest fungal growth occurred on ground seeds with 0.86 aw at 20 °C. There was no fungal growth for either A. flavus or A. parasiticus at 0.82 aw. The most rapid growth conditions for A. flavus and A. parasiticus were 0.94 aw at 35 °C, and 0.94 aw at 20 °C, respectively. Aspergillus flavus produced aflatoxins (13 μg/kg aflatoxin B1) only on seeds with 0.94 aw at 27 °C, while A. parasiticus produced high levels of aflatoxins under several conditions; the highest concentrations of aflatoxin B1 (175 μg/kg) and AFG1 (153 μg/kg) were produced on deoiled ground seeds with 0.94 aw at 27 °C. It is likely that storing ground deoiled nyjer seeds with a water activity up to 0.82 aw at 20 °C will reduce fungal growth aflatoxin production.

scholarly journals In Vitro Activity of Balanites aegyptiaca and Tamarindus indica Fruit Extracts on Growth and Aflatoxigenicity of Aspergillus flavus and A. parasiticus

2013 ◽  
Vol 2 (4) ◽  
pp. 68 ◽  
Author(s):  
Saifeldin Ahmed El-nagerabi ◽  
Abdulkadir E. Elshafie ◽  
Mohamed R. Elamin
Keyword(s):  
Aspergillus Flavus ◽  
Fungal Growth ◽  
Aflatoxin Contamination ◽  
Tamarindus Indica ◽  
Balanites Aegyptiaca ◽  
Total Aflatoxin ◽  
Animal Products ◽  
Fruit Extracts ◽  
Aflatoxin B

<p>Aflatoxin and especially aflatoxin B<sub>1</sub> (AFB<sub>1</sub>) is a carcinogenic secondary metabolite synthesized by certain <em>Aspergillus </em>species. They contaminate natural and processed agricultural and animal products which render them unfit for consumption. The aim of this study was to evaluate the <em>in vitro</em> effects of <em>Balanites aegyptiaca</em> and <em>Tamarindus indica</em> fruit extracts on the growth and aflatoxin secretion of <em>Aspergillus flavus</em> (SQU21) and <em>A. parasiticus </em>(CBS921.7) strains. The two fruit extracts significantly (<em>P </em>&lt; 0.05) reduced aflatoxin and did not inhibit mycelial dry weights of the two <em>Aspergillus </em>strains. At different concentrations of balanites (2.5-10%), the inhibition of total aflatoxin was 49.9-84.8% for <em>A. flavus</em> (SQU21) and 32.1-84.4% for <em>A. parasiticus</em> (CBS921.7), whereas the inhibition of aflatoxin Bwas 38.2-81.4% and 32.8-80.6% for the two strains. Tamarind fruit extract (2.5-7.5%) caused 28.8-84.2% and 40.7-85.5% reductions in total aflatoxin and 37.1-83.5% and 33.9-85.9% in aflatoxin B for the two strains, respectively. None of these extracts inhibited the fungal growth or detoxified synthetic aflatoxin B<sub>1</sub>. We have concluded that these fruits contain various inhibitors to aflatoxin biosynthesis and secretion. Therefore, they can be used in combination as safe green biopreservatives to combat aflatoxin contamination of food.</p>

No Effect of Soybean Lipoxygenase on Aflatoxin Production in Aspergillus flavus–Inoculated Seeds

2002 ◽  
Vol 65 (12) ◽  
pp. 1984-1987 ◽  
Author(s):  
J. E. MELLON ◽  
P. J. COTTY
Keyword(s):  
Aspergillus Flavus ◽  
Fungal Pathogens ◽  
Seed Viability ◽  
Soybean Seed ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Soybean Seeds ◽  
Heat Treated ◽  
Significant Difference

Soybean lines lacking lipoxygenase (LOX) activity were compared with soybean lines having LOX activity for the ability to support growth and aflatoxin B1 production by the fungal seed pathogen Aspergillus flavus. Whole seeds, broken seeds, and heat-treated (autoclaved) whole seeds were compared. Broken seeds, irrespective of LOX presence, supported excellent fungal growth and the highest aflatoxin levels. Autoclaved whole seeds, with or without LOX, produced good fungal growth and aflatoxin levels approaching those of broken seeds. Whole soybean seeds supported sparse fungal growth and relatively low aflatoxin levels. There was no significant difference in aflatoxin production between whole soybean seeds either with or without LOX, although there did seem to be differences among the cultivars tested. The heat treatment eliminated LOX activity (in LOX+ lines), yet aflatoxin levels did not change substantially from the broken seed treatment. Broken soybean seeds possessed LOX activity (in LOX+ lines) and yet yielded the highest aflatoxin levels. The presence of active LOX did not seem to play the determinant role in the susceptibility of soybean seeds to fungal pathogens. Seed coat integrity and seed viability seem to be more important characteristics in soybean seed resistance to aflatoxin contamination. Soybean seeds lacking LOX seem safe from the threat of increased seed pathogen susceptibility.

scholarly journals Evaluation of antifungal activity of Pittosporum undulatum L. essential oil against Aspergillus flavus and aflatoxin production

2011 ◽  
Vol 35 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Rosane Tamara da Silva Medeiros ◽  
Edlayne Gonçalez ◽  
Roberto Carlos Felicio ◽  
Joana D'arc Felicio
Keyword(s):  
Essential Oil ◽  
Essential Oils ◽  
Aspergillus Flavus ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Plant Oils ◽  
Food Commodities ◽  
And Storage ◽  
Main Producer ◽  
Mycelial Development

The presence of mycotoxins as a result of fungal attack can occur before, after and during the harvest and storage operations on agricultural crops and food commodities. Considering the inhibitory property of essential plant oils on the mycelial development of fungi and the importance of Aspergillus flavus, the main producer of aflatoxins, this research was designed to evaluate the toxicity of essential oil from Pittosporum undulatum against A. flavus. The essential oils were obtained from P. undulatum leaves, collected in different months and analyzed by GC/MS. The oils were rich in hydrocarbon, monoterpenes and sesquiterpenes and it was observed a significant variation on the chemical composition of the essential oil of leaves at different months. Besides, the essential oils were tested against fungal growth and the results showed different spectrum of inhibition on A. flavus. However, the essential oils inhibited the aflatoxin B1 production.

scholarly journals Post-harvest control of aflatoxin production in in-shell moist peanuts with sodium ortho-phenylphenate: III. Storage tests

1994 ◽  
Vol 51 (2) ◽  
pp. 369-373 ◽  
Author(s):  
H. Fonseca ◽  
C.R. Gallo ◽  
M.A. Calori-Domingues ◽  
E.M. Gloria ◽  
P.J. Approbatto ◽  
...  
Keyword(s):  
Uniform Distribution ◽  
Aspergillus Flavus ◽  
Rainy Season ◽  
Present Experiment ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Dry Season ◽  
Naked Eye ◽  
Spray System ◽  
Cleaning Machine

The present experiment aimed to evaluate the effect of sodium ortho-phenylphenate (SOP) application to in-shell moist peanuts for the control of aflatoxin production. Previous studies showed the need to improve the SOP solution distribution on peanut pods to evaluate the product. Thus, in this experiment the place of the spray system was the bag filler pipe of the pre-cleaning machine in the warehouse. In the 1989 rainy season two lots of 120 bags of in-shell moist peanuts were sprayed with 0.5 and 1% SOP solutions and aflatoxin production was not controlled. In the dry season of 1989 and in the rainy season of 1990, in-shell moist peanuts were sprayed with 5% SOP solution. The coverage of pods with the solution was efficient, allowing a uniform distribution of SOP solution on the pods. The results showed that only the 5.0% concentration of SOP solution utilized controlled the external fungal growth when a naked eye observation was made, however did not control aflatoxin production when applied to in-shell moist peanuts, probably due to the internal presence of Aspergillus flavus and because the fungicide could not penetrate inside to reach the kernels.

Fungal Growth and Aflatoxin Production on Apiarian Substrates

1977 ◽  
Vol 60 (1) ◽  
pp. 96-99
Author(s):  
Jo Ann L Hilldrup ◽  
Thomas Eadie ◽  
Gerald C Llewellyn
Keyword(s):  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Brood Comb

Abstract Unprocessed honey, Lilium longiflorium pollen, brood comb, whole larvae, and whole bees were inoculated with Aspergillus flavus NRRL 3251, A. flavus ATCC 15548, and A. parasiticus NRRL 2999. The fungi grew, sporulated, and produced various amounts of aflatoxin on all substrates except the unprocessed honey. The largest quantity of aflatoxin B1 was produced on whole larvae supporting A. flavus NRRL 3251 growth. A. parasiticus NRRL 2999 growing on whole larvae produced the most aflatoxin G1. Aflatoxins B2 and G2 were seldom detected. Apiarian substrates with the exception of honey seem capable of supporting fungal growth and resultant aflatoxin production.

scholarly journals Inhibition of Aflatoxin Production by Paraquat and External Superoxide Dismutase in Aspergillus flavus

Toxins ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 107 ◽  
Author(s):  
Tomohiro Furukawa ◽  
Shohei Sakuda
Keyword(s):  
Superoxide Dismutase ◽  
Aspergillus Flavus ◽  
Regulatory Protein ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Sod Activity ◽  
Fungal Cell ◽  
Cell Extracts ◽  
Ic50 Value

Aflatoxin contamination of crops is a worldwide problem, and elucidation of the regulatory mechanism of aflatoxin production, for example relative to the oxidative–antioxidative system, is needed. Studies have shown that oxidative stress induced by reactive oxygen species promotes aflatoxin production. However, superoxide has been suggested to have the opposite effect. Here, we investigated the effects of the superoxide generator, paraquat, and externally added superoxide dismutase (SOD) on aflatoxin production in Aspergillus flavus. Paraquat with an IC50 value of 54.9 µM inhibited aflatoxin production without affecting fungal growth. It increased cytosolic and mitochondrial superoxide levels and downregulated the transcription of aflatoxin biosynthetic cluster genes, including aflR, a key regulatory protein. The addition of bovine Cu/ZnSOD to the culture medium suppressed the paraquat-induced increase in superoxide levels, but it did not fully restore paraquat-inhibited aflatoxin production because bovine Cu/ZnSOD with an IC50 value of 17.9 µg/mL itself inhibited aflatoxin production. Externally added bovine Cu/ZnSOD increased the SOD activity in fungal cell extracts and upregulated the transcription of genes encoding Cu/ZnSOD and alcohol dehydrogenase. These results suggest that intracellular accumulation of superoxide impairs aflatoxin production by downregulating aflR expression, and that externally added Cu/ZnSOD also suppresses aflatoxin production by a mechanism other than canonical superoxide elimination activity.

scholarly journals A Corn Trypsin Inhibitor with Antifungal Activity Inhibits Aspergillus flavus α-Amylase

1999 ◽  
Vol 89 (10) ◽  
pp. 902-907 ◽  
Author(s):  
Z.-Y. Chen ◽  
R. L. Brown ◽  
J. S. Russin ◽  
A. R. Lax ◽  
T. E. Cleveland
Keyword(s):  
Aspergillus Flavus ◽  
Trypsin Inhibitor ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Inhibitory Effect ◽  
Starch Metabolism ◽  
Potato Dextrose Broth ◽  
The Relationship ◽  
Corn Trypsin Inhibitor

In this study, we found that the inhibition of fungal growth in potato dextrose broth (PDB) medium by the 14-kDa corn trypsin inhibitor (TI) protein, previously found to be associated with host resistance to aflatoxin production and active against various fungi, was relieved when exogenous α-amylase was added along with TI. No inhibitory effect of TI on fungal growth was observed when Aspergillus flavus was grown on a medium containing either 5% glucose or 1% gelatin as a carbon source. Further investigation found that TI not only inhibited fungal production of extracellular α-amylase when A. flavus was grown in PDB medium containing TI at 100 μg ml-1 but also reduced the enzymatic activity of A. flavus α-amylase by 27%. At a higher concentration, however, TI stimulated the production of α-amylase. The effect of TI on the production of amyloglucosidase, another enzyme involved in starch metabolism by the fungus, was quite different. It stimulated the production of this enzyme during the first 10 h at all concentrations studied. These studies suggest that the resistance of certain corn genotypes to A. flavus infection may be partially due to the ability of TI to reduce the production of extracellular fungal α-amylase and its activity, thereby limiting the availability of simple sugars for fungal growth. However, further investigation of the relationship between TI levels and fungal α-amylase expression in vivo is needed.

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