Abstract:The inhibitory activity of Bacillus cereus XZ30-2 against Aspergillus niger was evaluated and the stability of its fermentation supernatant was analyzed. The control effect of lyophilized powder prepared from the fermentation supernatant against A. niger was also studied, and its safety was evaluated in mice. B. cereus XZ30-2 strongly inhibited A. niger growth. The antagonistic bandwidth was 5.32 mm and the inhibitory rate of the fermentation supernatant was 54.31%. The XZ30-2 fermentation supernatant was stable under conditions of ultraviolet light irradiation, sunlight, and pH 5~9. Its antifungal activity began to decrease at 70 ℃. A total of 150 mg lyophilized powder could be prepared from 100 mL fermentation supernatant. The biocontrol efficacy of the lyophilized powder was evaluated using Zhengmai 366. In comparison with the control group, there was no obvious formation of A. niger colonies in the treatment group, indicating good antifungal properties of the XZ30-2 fermentation supernatant. The safety evaluation revealed that even after 14 days of XZ30-2 fermentation supernatant administration by gavage (maximum dose: 5000 mg/kg body weight), the mice demonstrated normal behavior and posture, normal weight gain, no signs of behavioral abnormalities, and no death. No pathological changes were noted in the organs harvested from the mice of the control and treatment groups. The organ and serological physiological indices were also comparable. Thus, XZ30-2 fermentation supernatant appeared to be safe. Collectively, these results provide theoretical basis for the further development and application of B. cereus XZ30-2 fermentation supernatant as an antifungal agent in food.
