, 2002; Kotan et al., 2009). Lactic acid bacteria (LAB) are a broad group of gram-positive, catalase-negative, non-sporulating, usually non-motile rods and cocci that utilize carbohydrates fermentatively and form lactic acid as the major end product (Onilude et al., 2005). LAB are widely used in food and feed fermentation, contributing to the hygienic safety, storage stability and attractive sensory properties (Laitila 3-Methyladenine supplier et al., 2002; Savadogo et al., 2006). These bacteria are important in the biopreservation of food and feed, related mainly to the production of antimicrobial
compounds, such as organic acids, i.e. lactic and acetic acid, hydrogen peroxide, and other antimicrobial compounds as bacteriocins (Messens & De Vuyst, 2002; Prachyakij et al., 2007). There is an increasing interest to find LAB strains that are able to
limit fungal growth and consequently mycotoxin production, in this particular case of aflatoxigenic fungi (Yang & Clausen, 2005; Aryantha & Lunggani, 2007; Elsanhoty, 2008). In previous in vitro and in vivo experiments with Lactobacillus rhamnosus L60 and Lactobacillus fermentum L23 we showed that these Sirolimus in vivo strains have probiotic characteristics (Pascual et al., 2008a ,b; Ruiz et al., 2009). Both strains have widespread antimicrobial activity mainly against bacteria and yeast, although there are no studies regarding the antagonistic effect of LAB on filamentous fungi. Therefore, the aim of this study was to evaluate antifungal activity and anti-aflatoxicogenic properties of L. rhamnosus strain L60 and L. fermentum strain L23 against toxigenic species of Aspergillus section Flavi. Lactobacillus rhamnosus L60 and L. fermentum L23 strains were obtained from a culture collection of the Bacteriology Laboratory at the National University of Río Cuarto, Córdoba, Argentina. These human strains were selected from among 100 strains of Lactobacillus on the basis of their probiotic characteristics
and bacteriocinogenic ability. The purity of the strains was confirmed by Gram staining. Strains were identified by standard biochemical tests (Holt, 1994), carbohydrate fermentation profile (Nigatu et al., 2000) and using the API 50 CHL system (BioMérieux, Marcy l’Etoile, France). The identification of L. rhamnosus L60 and L. fermentum Neratinib L23 was confirmed by 16S rRNA gene sequence analysis, and the sequences of these strains were registered in the GenBank database system (http://www.ncbi.nlm.nih.gov/sites/entrez) under accession numbers EF495247 (1402 bp) and GQ455406 (1523 bp), respectively. Both strains were grown in De Man Rogosa Sharpe (MRS) agar (Rogosa & Sharpe, 1963) at 37 °C, under a 5% CO2 atmosphere for 24 h. They were stored at –80 °C in MRS broth containing 30% (v/v) glycerol. A total of 137 Aspergillus section Flavi strains were recovered from brewer’s grains destined for pig feed in Argentina.