FOOD MICROBIOLOGY www.elsevier.nl/locate/jnlabr/yfmic Food Microbiology 21 (2004) 623–627 Short Communication Occurrence of Aspergillus species in mixed feeds and component raw materials and their ability to produce ochratoxin A F. Accensi*, M.L. Abarca, F.J. Caban˜es Departament de Sanitat i d’Anatomia Animals, Facultat de Veterin " aria, Universitat Aut " onoma de Barcelona, 08193 Bellaterra, Barcelona, Spain Received 7 July 2003; accepted 10 December 2003 Abstract The mycobiota of 147 samples of mixed feeds and 153 samples of raw materials (cereals and legumes) was studied in order to ascertain the occurrence of Aspergillus spp. and their ability to produce ochratoxin A (OTA). Total fungal counts ranged from o10 2 to 5.3  10 6 cfu/g. Aspergillus spp. (including teleomorphs) were isolated from 77.7% of the samples and ranged from non-detectable to 5.3  10 6 cfu/g with a mean value of 2.2  10 4 cfu/g. On average, Aspergillus spp. comprised 15.6% of the total fungal population. Aspergillus spp. were present in 94.4% of legume samples and 89.8% of mixed feeds, whereas in cereal samples Aspergillus spp. had a much lower occurrence (57.3%). Fourteen Aspergillus spp. (including teleomorphs) were identified. The predominant species were A. flavus, Eurotium chevalieri, E. amstelodami, and E. rubrum. Among the OTA-producing aspergilli only A. niger var. niger and A. ochraceus were isolated in this survey. Aspergillus niger var. niger was detected in 23% of the samples, whereas A. ochraceus was present in 7.3%. Three out of 52 of the A. niger var. niger isolates (5.8%) and one out of 20 A. ochraceus strains (5%), were able to produce OTA. r 2004 Elsevier Ltd. All rights reserved. Keywords: Aspergillus; Eurotium; Mycobiota; Mixed feeds; Cereals; Legumes; Ochratoxin A; A. niger var. niger; A. ochraceus 1. Introduction Commercial mixed feeds are a basic element in modern animal production. They contain, among other ingredients, mixtures of home grown cereals and imported commodities. The use of such ingredients inevitably leads to the contamination of the final mixed feed with molds (Chelkowski, 1991). Aspergillus and its teleomorphs Emericella and Euro- tium are usually reported as contaminants on a wide range of organic substrates, especially in stored grains and feedstuffs (Kozakiewicz, 1989; Pitt and Hocking, 1997). Aspergilli are certainly among the most impor- tant mycotoxin-producing fungi. Among the mycotox- ins they produce, Ochratoxin A (OTA) is receiving major attention because of its nephrotoxic, carcino- genic, teratogenic and immunosuppressive properties (Creppy, 1999). OTA occurs in cereals and cereal-based foods and has been associated with porcine nephropathy through contaminated feed (Krogh et al., 1973). Human exposure is possible by direct consumption of contami- nated plant products or indirectly, by consumption of meat or derived products from animals which were fed a diet containing OTA. OTA has been classically asso- ciated, though inconclusively, to Balkan Endemic Nephropathy and has been recently related to human renal disorders in Egypt and Tunisia (Creppy, 1999). In an attempt to control such a hazard, the European Union has recently established maximum levels of this mycotoxin for cereals and dried vine fruits (Anonymous, 2002). OTA was first described as a metabolite of A. ochraceus (van der Merwe et al., 1965) and later of some closely related species from Aspergillus section Circum- dati (Ciegler, 1972; Varga et al., 1996) and Penicillium verrucosum (Pitt, 1987). More recently, A. niger var. niger (Abarca et al., 1994a) and A. carbonarius (Horie, 1995) have also been described as OTA-producers. The origin of OTA in cool and temperate climates is generally attributed to P. verrucosum, whereas in warm temperate and tropical zones it is now commonly associated with A. ochraceus and the black aspergilli (Pitt, 2000; Abarca et al., 2001). Bayman et al. (2002) ARTICLE IN PRESS *Corresponding author. Tel.: +34-93-581-10-88; fax: +34-93-581- 20-06. E-mail address: francesc.accensi@uab.es (F. Accensi). 0740-0020/$ - see front matter r 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.fm.2003.12.003