Submitted to: Letters in Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2005
Publication Date: 11/1/2005
Citation: Ni, X., and Streett, D. A. 2005. Modulation of water activity on fungicide effect on Aspergillus niger growth in sabouraud dextrose agar medium. Letters in Applied Microbiology. 41:428-433. Interpretive Summary: The mold, Aspergillus niger, is a major contaminant in insect rearing facilities and must be controlled to rear quality insects. Low water activity levels in combination with a fungicide were found to be a cost-effective management strategy to prevent A. niger contamination in semisolid insect artificial diets that are widely used in insect mass-rearing facilities. This information will benefit the insect rearing community and will improve insect rearing programs.
Technical Abstract: The objectives of this study were to assess the effects of low water activity (aw) in combination with low concentrations of fungicides on A. niger suppression in semisolid agar medium. In the present study, the impact of four aw levels (i.e., 0.994, 0.962, 0.921, and 0.854) and four concentrations (0, 1, 10, and 20 'M) of two new fungicides (i.e., amphotericin B and itraconazole) on A. niger spore germination and growth on a semisolid culture medium. Adjustment of aw (with 12.5% of glycerol) in combination with 1 'M of itraconazole can effectively reduce or prevent A. niger contaminations in semisolid SDA culture medium. Low aw in combination with 1 'M of itraconazole was one of the most cost-effective management strategies to prevent A. niger contamination in semisolid insect artificial diets that are widely used in insect mass-rearing facilities.