Effect of ultraviolet light irradiation on viability and aflatoxin production by Aspergillus parasiticus

Abstract

The effect of ultraviolet light irradiation (254 nm) on both the viability and the aflatoxin-producing ability of the fungus Aspergillus parasiticus NRRL 2999, a good aflatoxin-producing strain, was studied. This strain showed noticeable resistance and irradiation for more than 10 min was necessary to reduce survival to under 10%, while the white mutants were more susceptible (5 min of irradiation reduced survival to under 1%). Induction of mutants with complete loss of aflatoxigenicity was rare and only 3 of the 1463 survivors tested were aflatoxinless.

Ultraviolet irradiation detoxification of aflatoxins

“…According to the published literature, some researchers used UVC (254 nm or 265 nm) to inhibit the survival of A. parasiticus and other aflatoxigenic fungi, and then significantly reduced aflatoxin production in foods (Atalla et al, 2004;Basaran, 2009;Jubeen et al, 2012;Moreno, Ramos, Gonz alez, & Su arez, 1987;Samarajeewa & Gamage, 1988). While others used UVA (362 nm or 365 nm) to effectively reduce the aflatoxin in foods (Samarajeewa et al, 1985;Tripathi & Mishra, 2010;Yousef & Marth, 1986).…”

“…Considering the quality of irradiated foods, the irradiation time should be restricted in a proper range. Normally, the detoxification of aflatoxin can be achieved within 10e60 min depending upon the conditions: state and thickness of the foods, UV wavelength and intensity, and contaminated levels of aflatoxins, and so on (Atalla et al, 2004;Jubeen et al, 2012;Liu et al, 2011;Moreno et al, 1987;Tripathi & Mishra, 2010).…”

Ketosynthase Domain Probes Identify Two Subclasses of Fungal Polyketide Synthase Genes

“…wA is required for the production of a heptaketide intermediate in the biosynthesis of a dark green conidial pigment which confers resistance to ultraviolet light (Aramayo et al, 1989;Watanabe et al, 1999). Green to blueish-green conidial pigments with similar properties have also been identified in A. parasiticus (Moreno et al, 1987) and P. cyclopium (Ha-Huy-Kê and Luckner, 1979). The minor A. parasiticus PCR product may well be involved in biosynthesis of the putative conidial pigment intermediate parasperone A, which is also a heptaketide and is structurally very similar to the product of A. nidulans WA (Brown et al, 1993;Watanabe et al, 1999).…”

Transformation of Aspergillus parasiticus using autonomously replicating plasmids from Aspergillus nidulans

“…The A. parasiticus mutant strains used in this study derive from the parental strain A. parasiticus NRRL 2999. The previously obtained green non-aflatoxin-producing mutant M73(05-10) [12], was mutagenized with UV light (254 nm) at low dose [13], and a green ArgB mutant designated AP009 was selected using the NovoZym enrichment method [14,15]. The white ArgB mutant AP009B2 used as recipient of the transformation system was obtained by the same UV procedure from AP009 by visual selection.…”