**5. Concluding remarks and future prospective**

AF contamination of food and feed remains a major risk for human and animal health all over the world. Despite the long history of our knowledge about AF, little has been documented on how we can virtually combat the global distress of AF contamination of crops and agricultur‐ al commodities. AF-producing fungi can infect grains from pre-harvest conditions in the field through to post-harvest stages in the stores. Several pre- and post-harvest strategies have be‐ ing tested to reduce risk of AF contamination. One of the management strategies being devel‐ oped is biological control using various antagonistic microorganisms such as fungi, bacteria, and actinomycetes by a competitive exclusion mechanism. Biological control in conjunction with other management practices has potential to dramatically reduce AF contamination. Nat‐ ural population of *A. flavus* consists of toxigenic strains that produce considerable amount of AF and atoxigenic strains that lack the capacity to produce AF. Nowadays, introducing atoxi‐ genic strains has been successfully used to compete and exclude toxigenic strains in the field thereby reducing AF production in contaminated crops. However, there are some important limitations from the type of vegetative compatibility groups which shows the progeny of the fungus for AF-producing ability to geographic limitations in selection of atoxigenic strains. Considerable tolerance of *B. subtilis* and *P. chlororaphis* to environmental stresses, their large ca‐ pacity for producing diverse array of beneficial antifungal metabolites and their readily pro‐ ducing by current fermentation technology make them promising tools for biocontrol of aflatoxigenic fungi in practice. Bacterial population from the genera *Bacillus* and *Pseudomonas* identified in pistachio, maize and peanut fields in the present study with potent antagonistic activity against aflatoxigenic *Aspergillus parasiticus* can potentially be developed into new bio‐ control agents for combating AF contamination of crops in the field. These bacteria must be evaluated for a set of selection criteria for further use in biocontrol field experiments. Inabili‐ ty to produce toxic substances for biological systems and propensity to multiply, colonize and survive are the most important selection criteria to make sure that the selected antagonistic bacterial strains are safe and applicable when they introduced in to the environment. This en‐ deavor shows biological control holds promise of offering a long-term solution for coloniz‐ ing crops with aflatoxigenic fungi and thereby reducing AF contamination in the field.

[5] Barrow, G. I., & Feltham, R. K. A. (1993). Cowan and Steel's manual for the identifica‐ tion of medical bacteria, 3rd ed. Cambridge University Press, Cambridge, United

Terrestrial Bacteria from Agricultural Soils: Versatile Weapons against Aflatoxigenic Fungi

http://dx.doi.org/10.5772/45918

37

[6] Bennett, J. W., & Klich, M. (2003). Mycotoxins. *Clinical Microbiology Reviews*, 16,

[7] Hedayati, M. T., Pasqualetto, A. C., Warn, P. A., Bowyer, P., & Denning, D. W. (2007). Aspergillus flavus: human pathogen, allergen and mycotoxin producer. *Microbiology*,

[8] Bloom, B., Ehlers, R., Haukeland-Salinas, S., Hoddanen, H., & Jung, K. (2003). Biologi‐

[9] Brown, R. L., Cotty, P. J., & Cleveland, T. E. (1991). Reduction in aflatoxin content of maize by atoxigenic strains of Aspergillus flavus. *Journal of Food Protection*, 54, 623-626.

[10] Bull, C. T., Shetty, K. G., & Subbarao, K. V. (2002). Interactions between myxobacteria,

[11] Clark, A. M. (1996). Natural products as a resource for new drugs,. *Pharmaceutical Re‐*

[12] Cole, J. R., Chai, B., Farris, R. J., Wang, Q., Kulam, S. A., McGarrell, D. M., Garrity, G. M., & Tiedje, J. M. (2005). The Ribosomal Database Project (RDP-II): sequences and

[13] Cook, R. J. (1993). Making greater use of introduced microorganisms for biological

[14] DeBach, P., & Rosen, D. (1991). Biological control by natural enemies. Cambridge Uni‐

[15] Donner, M., Atehnkeng, J., Sikora, K. A., Bandyopadhyay, R., & Cotty, P. J. (2010). Mo‐ lecular characterization of atoxigenic strains for biological control of aflatoxins in Ni‐ geria. *Food Additives & Contaminants: Part A: Chemistry, Analysis, Control, Exposure &*

[16] Dorner, J. W., Cole, R. J., & Blankenship, P. D. (1998). Effect of inoculum rate of bio‐ control agents on preharvest aflatoxin contamination of peanuts. *Biological Control*, 12,

[17] Dorner, J. W., Cole, R. J., & Wicklow, D. T. (1999). Aflatoxin reduction in corn through field application of competitive fungi. *Journal of Food Protection*, 62, 650-656.

[18] Gregersen, T. (1978). Rapid method for distinction of Gram-negative from Gram-posi‐ tive bacteria. *European Journal of Applied Microbiology and Biotechnology*, 5, 123-127.

tools for high-throughput rRNA analysis. *Nucleic Acids Research*, 33, D294-296.

control of plant pathogens. *Annual Review of Phytopathology*, 31, 53-80.

cal control agents: Safety and regulatory policy. *BioControl*, 48, 477-484.

plant pathogenic fungi and biocontrol agents. *Plant Disease*, 86, 889-896.

Kingdom.

497-516.

153, 1677-1692.

*search*, 13, 1133-1141.

versity Press, New York.

*Risk Assessment*, 27, 576-590.

171-176.
