Aflatoxin production

Nartowicz, V. B., Buchanan, R. L., Segall, S., Aflatoxin production in regular and decaffeinated coffee beans, J. Food Sci., 44, 446, 1979. (CA90 166747g)... 

Soil populations and aflatoxin contamination are influenced by weather patterns, with hot dry soils favoring the Aspergillus section Flavi. In terms of geographic location, A. flavus incidence is correlated with high minimum temperatures and inversely correlated to latitude. For example, corn ears that develop at temperatures of 28 to 32°C are far more likely to be contaminated by aflatoxin than ears grown later in the season at lower temperatures. However, late planting is not economically feasible due to lower crop yields. Besides hot dry weather, the level of insect and rodent activity in an area may also substantially favor colonization and aflatoxin production. Plant fertility, density, and disease also play roles in the level of aflatoxin contamination. 

Cyclopiazonic acid is synthesized by a number of Aspergillus and Penicillium spp. The Aspergillus spp. that have been reported as cyclopiazonic-acid producers are A. flavus (the most studied cyclopiazonic-acid producer) along with A. versicolor, A. oryzae, and A. tamarii. Among the Penicillium spp. producers are P. verrucosum, P. patulum, P. camembertii, and P. puberulum. In A. flavus, cyclopiazonic-acid production usually occurs in conjunction with aflatoxin production. However, studies of aflatoxin mutants have shown that synthesizing cyclopiazonic acid is independent of the capacity to synthesize aflatoxin (Horn and Dorner, 1999). Little is known about the impact of... 

The stages in commodity handling at which aflatoxin and other mycotoxins can be detected and their amounts modified are shown in Figure 9.4. Aspergillus spp. thrive in hot, humid, subtropical and tropical climates. When environmental conditions favor aflatoxin production, accumulation is rapid, both in the field and in storage. 

Jayashree, T., Praveen-Rao, J., and Subramanyam, C. (2000). Regulation of aflatoxin production by Ca2- -/calmodulin-dependent protein phosphorylation and dephosphorylation. FEMS Microbiol. Lett. 83, 215-219. 

Volatile compounds originating from the aflatoxin susceptible crop, cotton, and other plant-derived compounds that inhibit aflatoxin production have been identified. The various compounds are being tested for their potential to enhance host plant resistance by inhibition of fungal growth/aflatoxin production. 

Contamination of soybeans with Aspergillus flavus is found in approximately 50% of commercial samples. Fortunately, the incidence of aflatoxin from this route is quite low. Moisture at [he time of maturity, development of the seed in a closed pod, and binding of zinc by phytic acid are suggested as reasons for resistance of soybeans to aflatoxin production... 

Clove bud oil causes inhibition of both mycelial growth and aflatoxin production of A. parasiticus (Farag et al., 1989 Gowda et al., 2004). Clove oil, at concentrations > lOOpg/ml, results in reduction in the aflatoxin production in liquid cultures (Sinha et al., 1993). Clove oil inhibits the growth and production of fumonisin Bj by F. prolif-eratum (Veluti et al., 2003). 

Gowda, N.K.S., Malathi, V. and Suganthi, R.U. (2004) Effect of some chemical and herbal compounds on growth of Aspergillus parasiticus and aflatoxin production. Animal Food Science and Technology 11 6, 281-291. 

Sinha, K.K., Sinha, A.K. and Prasad, G. (1 993) The effect of clove and cinnamon oils on growth and aflatoxin production by Aspergillus flavus. Letters in Applied Microbiology 16(3), 11 4-11 7. 

Masood et al. (1994) tested capsanthin and capsaicin, the colouring and pungent principles of C. annuum, respectively, against growth and aflatoxin production of Aspergillus flavus in SMKY liquid medium. Capsanthin inhibited both the growth and toxin production of A. flavus completely at all concentrations tested (0.2, 0.6 and l.Omg/ml) until the 4th day of incubation. 

Selvi, A.T., Joseph, C.S. and Jayaprakasha, C.K. (2003) Inhibition of growth and aflatoxin production in Aspergillus flavus by Carcinia indica extract and its antioxidant activity. Food Microbiology 20(4), 455 160. 

Figure 26 Aflatoxin production inhibitors from pesticides and plants.

Figure 27 Aflatoxin production inhibitors from microorganisms.

Bhatnagar, D., Cary, J.W., Ehrlich, K. et al. (2006). Understanding the genetics of regulation of aflatoxin production and Aspergillus fiavus development. Mycopathologia 162 155-66. 

Aflatoxin production is best prevented by using appropriate storage techniques. 

Singh and Sumbali (2000) demonstrated that mature jujube fruits are a favorable substrate for infection and aflatoxin production by A. flavus strains. Among the mycoflora on the surface of jujube (Ziziphus mauritiana) A. flavus consistently was recorded during the entire period of fruit development. Fifty isolates of A. flavus isolated from the preharvest fruits caused extensive postharvest rot of mature jujube when inoculated. When all of these isolates were also screened for their aflatoxigenic potential in mature jujube, 54% of the isolates tested positive for different aflatoxins (Bi, B2, Gi, and G2) at levels ranging from 31 to 2874 pg/kg. 

Ouratea multiflora Pohl (leaves) Biflavonol. I-5,7,4 -Tri-0-methylkaempferol-(I-6,II-8)-II-5,7,3, 4 -tetra-O-methylquercetin (111) amentoflavone (1). Ouratea species are used for treatment of rheumatic and gastric ailments. Inhibitory activity on aflatoxin Bj and B2 production, but did not inhibit fungal growth. Therefore, suitable for the control of aflatoxin production. Felicio et al., 2001[310] Gonyalez et al., 2001[311]. 

Ouratea spectabilis (Mart.) Engl, (leaves) Succedaneaflavones [(1-6,11-6)-Biflavones]. (I-6,II-6)-Bigenkwanin (115) I-7,II-7-di-0-methylagathisflavone (104). Biflavones inhibited lens aldose reductase. The biflavonoids showed inhibitory activity on aflatoxin Bj and B2 production, but did not inhibit fungal growth at the concentration tested. Therefore, biflavonoids can be used for the development of agents to control aflatoxin production. Felicio et al., 1995[100]. Gon9alez et al., 2001 [311]. 

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