Skin damage, high temperature and relative humidity as detrimental factors for Aspergillus carbonarius infection and ochratoxin A production in grapes N. Bellı ´, S. Marı ´n, I. Coronas, V. Sanchis, A.J. Ramos * Food Technology Department, CeRTA-UTPV, University of Lleida, Av. Rovira Roure 191, 25198 Lleida, Spain Received 21 September 2005; received in revised form 21 February 2006; accepted 25 February 2006 Abstract This study investigated the impact of skin damage on Aspergillus carbonarius colonization and ochratoxin A (OTA) production in grapes at different temperatures and relative humidity. Four ochratoxigenic A. carbonarius strains isolated from wine grapes were used to inoculate artificially damaged and undamaged table grapes. Grapes were stored at three levels of relative humidity (80%, 90% and 100%) and at two temperatures (20 and 30 °C). After seven days, the infection percentage of A. carbonarius was recorded and OTA accu- mulation in berries was analysed. Damaged grapes were more commonly infected and development of colonies was higher than in undam- aged ones; consequently more OTA was detected in the former treatment. Temperature and relative humidity had significant influences on both infection and toxin content. The amount of OTA detected at 30 °C was higher than at 20 °C in most of the treatments. The highest relative humidity (100%) led to maximum amounts of OTA while no significant differences were found between 90% and 80% in the OTA content. The implementation of preventive measures in order to minimise berry damage in the field by controlling pathogenic fungi and insects during grape growing and removing visibly damaged grapes at harvest may significantly reduce OTA contamination in grapes. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Ochratoxin A; Aspergillus carbonarius; Grapes; Skin damage; Temperature; Relative humidity 1. Introduction Ochratoxin A (OTA) is a mycotoxin considered to be a possible carcinogen for humans (IARC, 1993). It has been shown to be nephrotoxic, carcinogenic, teratogenic and immunosuppressive in laboratory animals (Boorman, 1989; Dirheimer, 1998). It has been commonly found in cereals but it can also contaminate a variety of other plant and animal products. Grapes and wine contain important amounts of OTA, in particular, wine consumption could represent 15% of the total intake of this toxin (Codex Ali- mentarius Commission, 1998). Therefore, studies on these products aiming to reduce the consumer exposure to the toxin as much as possible are crucial. OTA was originally isolated in 1965 as a metabolite from a strain of Aspergillus ochraceus (Van der Merwe, Steyn, Fourie, Scott, & Theron, 1965). Recently, OTA production has been reported from Aspergillus species belonging to the Nigri section, which are frequently isolated from grapes (Battilani et al., 2003; Bellı ´ et al., 2004; Bellı ´, Mitchell et al., 2004; Sage, Krivobok, Delbos, Seigle-Murandi, & Creppy, 2002; Serra, Abrunhosa, Kozakiewicz, & Venancio, 2003; Tjamos et al., 2004). In this section, the reported OTA- producing species are A. carbonarius and those now included in the so-called A. niger aggregate (Abarca, Accensi, Bragu- lat, & Caban ˜es, 2001). A. carbonarius is less common than A. niger, but is the main species responsible for OTA in grapes because almost all strains are high OTA producers (Battilani et al., 2003; Bellı ´, Mitchell et al., 2004; Caban ˜ es et al., 2002). A preliminary study reported the ability of strains of A. carbonarius to colonise and penetrate intact and 0956-7135/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodcont.2006.02.014 * Corresponding author. Tel.: +34 973 702811; fax: +34 973 702596. E-mail address: ajramos@tecal.udl.es (A.J. Ramos). www.elsevier.com/locate/foodcont Food Control 18 (2007) 1343–1349