Inhibition of Aspergillus parasiticus Speare by Cladosporium fulvum Cooke in peanuts

Complete inhibition of Aspergillus parasiticus was effected by the crude extract at 100 ug in peanut kernels with 5.3 to 8.25 percent moisture content [MC] up to 6 months. At 80 to 30 ug, growth was inhibited only at 5.3 percent MC but normal and luxuriant growth was evident at 8.25 percent MC. Complete inhibition of A. parasiticus was possible at 100 to 50 percent culture broth in peanut kernels with 5.2 to 5.4 percent MC up to 6 months. Normal and luxuriant growth was evident in peanut kernels with 8.50 to 8.72 percent MC even at 100 percent culture broth. Restricted and abnormal growth of A. parasiticus was evident in peanut kernels with 6.23 percent MC at 80 to 30 ug. Similar growth characteristics were observed in peanut kernels with 6.1 to 6.77 percent MC at 100 to 50 percent culture broth. Growth was characterized by localized, tiny fungal growths with yellow-greenish mycelia and spores indicating effective inhibition. The pH (4.0, 5.0, 6.0 and 7.0) of the culture broth exerted minimal effect on inhibition of A. parasiticus. Good growth was evident at all pH levels. However, mold counts were relatively higher at pH 5.0 and lower at pH 4.0. The effect of temperature on inhibition of A. parasiticus was also minimal. Abundant growth was evident at 29 deg C (room temperature) and 32 deg C at all concentrations of the crude extract and culture broth at relatively high MC. Growth inhibition was possible at both temperature only at low MC. Essentially, factors such as temperature, concentration and pH play minor roles in inhibition of A. parasiticus. Low MC is the most critical factor affecting inhibition of A. parasiticus in peanut kernels. If MC is low, A. parasiticus is inhibited even without treatment. Treatment however, is useful if MC is higher than 5.4 percent. A 100 percent germination test was possible for peanut kernels treated with the culture broth after one week and 85 to 86 percent after 3 months of storage at room temperature. The metabolite is non-toxic to test chicks. Normal growth and a 100 percent survival was evident in test chicks after continuous ad libitum feeding for 7 days