Influence of Temperature, pH, Water Activity and Antifungal Agents on Growth of Aspergillus flavus and A. parasiticus

Authors

  • G. U. HOLMQUIST,

    1. Authors Holmquist and Walker are with the Dept. of Food Technology and Author Stahr is with the Dept. of Veterinary Pathology, Iowa State Univ., Ames, IA 50011.
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  • H. W. WALKER,

    1. Authors Holmquist and Walker are with the Dept. of Food Technology and Author Stahr is with the Dept. of Veterinary Pathology, Iowa State Univ., Ames, IA 50011.
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  • H. M. STAHR

    1. Authors Holmquist and Walker are with the Dept. of Food Technology and Author Stahr is with the Dept. of Veterinary Pathology, Iowa State Univ., Ames, IA 50011.
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  • Journal Paper No. J-10807 of the Iowa Agriculture & Home Economics Experiment Station, Ames, Project No. 2365 and 2406.

  • Mention of a commercial product does not constitute an endorsement of the product.

ABSTRACT

Effect of temperature, pH, water activity, and nine antifungal agents on growth of Aspergillus flavus and A. parasiticus was determined on Sabouraud-Dextrose Agar and on corn. Maximal growth of the two molds occurred at 33°C, the highest temperature used, pH of 5.0 and aw of 0.99. At 15°C, growth was observed at aw of 0.95 but not 0.90. Slight growth was observed at an aw, of 0.85 at 27°C and 33°C. Nine antifungal agents (Botran, Orthocide, Poly-ram 80, Topsin-M, Thiram, Imazalil, sodium propionate, sodium sulfite and DDVP) were tested for inhibition of growth. Activity of the antifungals increased as the aw was decreased. All antifungals showed inhibitory activity, but Imazalil and DDVP were the most effective agents at the lowest concentrations.

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