Control of Aspergillus growth and aflatoxin production using natural maize phytochemicals under different conditions of water activity

NESCI, A; ETCHEVERRY, M.

PEST MANAGEMENT SCIENCE

JOHN WILEY & SONS LTD

Año: 2006 vol. 62 p. 775 - 784

1526-498X

Abstract: The effects of the natural phytochemicals trans-cinnamic acid (CA) and ferulic acid (FA) alone at concentrations of 1–25mM and in 16 combinations (M: mixtures) on growth and aflatoxin B1 production by Aspergillus flavus Link and A. parasiticus Speare were evaluated. Studies on growth rate and aflatoxin B1 production were carried out in vitro in relation to a water activity aw of 0.999, 0.971, 0.955 and 0.937. Overall, CA at concentrations of 10 and 20mM and FA–CAmixturesM3 (20 +5mM respectively),M8 (25 +5mM), M9 (1 + 10mM), M10 (10 + 10mM), M11 (20 + 10mM), M12 (25 + 10mM), M13 (1 + 20mM), M14 (10 + 20mM), M15 (20 + 20mM) and M16 (25 + 20mM) were the treatments most effective at inhibiting growth of the four species assayed. All strains were much more sensitive to all natural phytochemicals tested on growth rate at aw = 0.937. CA and the FA–CA mixtures M1 (1 +1mM respectively), M4 (25 +1mM), M5 (1 +5mM), M6 (10 +1mM), M7 (20 +1mM), M8 (25 +5mM), M9 (1 + 10mM), M10 (10 + 10mM), M11 (20 + 10mM), M12 (25 + 10mM), M13 (1 + 20mM), M14 (10 + 20mM), M15 (20 + 20mM) andM16 (25 + 20mM) completely inhibited aflatoxin B1 production by all strains at aw = 0.999, 0.971, 0.955 and 0.937. Decreased aflatoxin B1 levels in comparison with the control were observed with FA at 1, 10, 20 and 25mM with the strains RCM89, RCM108 and RCM38 at aw = 0.971, 0.955 and 0.999 respectively. The data show that CA and FA can be considered as effective fungitoxicants for A. flavus and A. parasiticus in in vitro assay. The information obtained is part of an ongoing study to determine their application at the storage level.