Lactobacillus casei CRL 431 and Lactobacillus rhamnosus CRL 1224 as biological controls for Aspergillus flavus strains

Centro de Referencia para Lactobacilos (CERELA)-CONICET, Chacabuco 145, 4000 Tucumán, Argentina.
Journal of food protection (Impact Factor: 1.85). 11/2006; 69(10):2544-8.
Source: PubMed


The effect of two species of lactobacilli, Lactobacillus casei CRL 431 and Lactobacillus rhamnosus CRL 1224, on growth of different Aspergillus flavus strains was determined. A. flavus strains (Ap, TR2, or CF80) were grown in LAPTg broth at 37 degrees C for 7 days as a single culture and in association with L. casei CRL 431 or L. rhamnosus CRL 1224 at initial inoculum ratios of 1:1, 1:10, and 1:100. In most cases, the mixed cultures had a lower fungal growth and a lower pH than the control cultures. Mycelial dry weight was reduced to 73 and 85% using L. casei CRL 431 and L. rhamnosus CRL 1224, respectively. The pH decrease in mixed cultures when the fungal mycelial dry weight is reduced may play an important role in inhibition. The number of viable bacteria was variably affected by fungal growth. These results indicate that L. casei CRL 431 and L. rhamnosus CRL 1224 may be useful as potential biocontrol agent against A. flavus.

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    • "It is possible, therefore, that this group of bacteria may be useful in developing targeted strategies for controlling fungi in agricultural systems. Another example of cultural experimentation to identify microbial antagonists of aflatoxigenic fungi is the characterization of the inhibitory activity of two Lactobacillus species against A. flavus (Bueno et al., 2006). Strains of L. casei, isolated from human feces, and L. rhamnosus, isolated from yogurt, both reduced growth of A. flavus strains in liquid co-culture, but not in agar diffusion assays. "
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