Effect Some Environmental Factors and Vitamins on Growth of Aspergillus flavus and Production Efficiency of Aflatoxin B1 and B2

	Effect Some Environmental Factors and Vitamins on Growth of Aspergillus flavus and Production Efficiency of Aflatoxin B1 and B2
journal of kerbala university
Article 1, Volume 7, Issue 2, 2011, Pages 53-63 PDF (0 K)
Abstract
Laboratory experiments were carried out in the postgraduate laboratories, Biology Department – College of Education / Kerbala University . The Study aimed to assess the effect of some environmental factors such as temperature, pH and relative humidity, and the vitamins A , E and C on the fungus A. flavus and production aflatoxin B1 and B2 . Results showed that, the rate of growth of fungus A. flavus was 4.83 cm at different temperatures, and 4.89 cm at different levels of pH and 5.88 cm at different levels of relative humidity . The temperature 55ºC at the pH equals to 6.5 and pH 3.5 at a temperature of 25ºC gave 100% of the inhibition of the fungus , while other levels of the three factors gave different rates of growth of the fungus. Aflatoxin B1 and B2 disappeared at the treatment of fungus at the temperatures 35 ºC and 55 ºC , while aflatoxin B2 disappeared at temperatures 25ºC and 45ºC , but both types of aflatoxin appeared at temperature 15ºC . Concerning pH , aflatoxin B1 and B2 appeared at pH ranged (5.6 to 5.9) , but at the level of pH 3.5 both types of aflatoxin disappeared when pH was equal to 5 , type B1 appeared with the temperature at all levels of 25 ºC . Concerning relative humidity, aflatoxin B1 appeared at RH equals to 20, 65 and 80, while both types disappeared at the level of RH equals to 50, but at the level of RH equals to 35, only type B2 appeared . Vitamins were used in concentrations (1, 2 and 3) mg / ml to study their impact on the growth of fungus A.flavus in the Potato Dextrose Agar (PDA) containing these vitamins. vitamin A showed an impaction on the other vitamins in the impact of inhibitory of growth of fungus A. flavus , the lowest growth of the fungus was 3.05 cm .vitamin E came in the second rank among the vitamins in the impact of inhibitory as it gave the growth rate of 4.52 cm , then vitamin C came in the last rank , which gave a growth rate of 5.48 cm. It was found that the increase concentrations of any type of vitamins increased the inhibition of fungus as the focus of 3 mg / ml of vitamin A inhibit fungus growth by 100% , while the other concentrations of vitamin A and other vitamins inhibited the growth of fungus, but to a lesser extent . Vitamin E exceeded the rest of the vitamins as it inhibited the production of aflatoxin B2 at all concentrations, while vitamin A inhibited the production of aflatoxin B2 at a concentration of (3 and 2) mg / ml , and vitamin C came in the last rank, as it inhibited the production of aflatoxin B2 at a concentration of 3 mg / ml .

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