Inactivation of Aspergillus flavus spores by curcumin-mediated photosensitization Benigni A. Temba a , Mary T. Fletcher a , Glen P. Fox a , Jagger J.W. Harvey a, b , Yasmina Sultanbawa a, * a Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Health and Food Sciences Precinct, Coopers Plains, QLD, 4108, Australia b Biosciences Eastern and Central Africa- International Livestock Research Institute (BecA-ILRI) Hub, Nairobi, 00100, Kenya article info Article history: Received 24 March 2015 Received in revised form 9 June 2015 Accepted 20 June 2015 Available online 23 June 2015 Keywords: Curcumin Mycotoxigenic fungi Photosensitization abstract Minimizing fungal infection is essential to the control of mycotoxin contamination of foods and feeds but many potential control methods are not without their own safety concerns for the consumers. Photo- dynamic inactivation is a novel light-based approach which offers a promising alternative to conven- tional methods for the control of mycotoxigenic fungi. This study describes the use of curcumin to inactivate spores of Aspergillus flavus, one of the major aflatoxin producing fungi in foods and feeds. Curcumin is a natural polyphenolic compound from the spice turmeric (Curcuma longa). In this study the plant has shown to be an effective photosensitiser when combined with visible light (420 nm). The experiment was conducted in in vitro and in vivo where A. flavus spores were treated with different photosensitiser concentration and light dose both in buffer solution and on maize kernels. Comparison of fungal load from treated and untreated samples was determined, and reductions of fungal spore counts of up to 3 log CFU ml 1 in suspension and 2 log CFU g 1 in maize kernels were obtained using optimal dye concentrations and light dose combinations. The results in this study indicate that curcumin- mediated photosensitization is a potentially effective method to decontaminate A. flavus spores in foods and feeds. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Some fungi that colonise agricultural commodities and food- stuffs may produce toxic secondary metabolites known as myco- toxins. Mycotoxin contamination in food and feed is reported to be a global problem (Rodrigues & Chin, 2012; Rodrigues, Handl, & Binder, 2011; Rodrigues & Naehrer, 2012a, 2012b) and occur in more than 25% of different key foods in Africa (Wagacha & Muthomi, 2008). These fungal toxins pose serious health prob- lems to humans and animals including instant death in acute cases, and cancers; and studies also suggest that they cause immuno- suppression, retard growth, and reproductive disorders with chronic exposures (Probst, Njapau, & Cotty, 2007; Varga, Frisvad, & Samson, 2009). In addition to health impacts, significant economic losses result from lowered animal production, decreased market values, regularity losses and secondary effects on agricultural production and agricultural communities (Wu, 2006, 2007). Due to these impacts, a worldwide concerted effort has been applied to control and regulate the occurrence of these toxins in food and animal feed. Methods to control mycotoxin occurrence in food and animal feed focus on either preventing fungal colonisation and mycotoxin production, or where this fails, removal of the toxins in the food and feed by detoxification (Leslie & Logrieco, 2014). Fungal contami- nation of crops and their subsequent toxin production can occur in the field before harvest, or during post-harvest storage and pro- cessing. Control methods range from the application of fungicides and pesticides that kill the fungi directly or reduce contamination by insect vectors, to fungal inactivation by thermal, chemical or photo-irradiation procedures (Begum, Hocking, & Miskelly, 2009; Luksiene, Peciulyte, Jurkoniene, & Puras, 2005; Nemt ¸ anu, Bras ¸ oveanu, Karaca, & Erper, 2014). However, no single method has been successful in combating the mycotoxin problem entirely and it is advocated to deal with the problem by integrating various intervention measures depending on circumstances. * Corresponding author. E-mail address: y.sultanbawa@uq.edu.au (Y. Sultanbawa). Contents lists available at ScienceDirect Food Control journal homepage: www.elsevier.com/locate/foodcont http://dx.doi.org/10.1016/j.foodcont.2015.06.045 0956-7135/© 2015 Elsevier Ltd. All rights reserved. Food Control 59 (2016) 708e713