The present invention relates to a bacterium of the species Lactobacillus fermentum having the ability to inhibit the growth of the fungus Penicillium solitum deposited under the accession No.: DSM32093 or the growth of the fungus Penicillium brevicompactum deposited under the accession No.: DSM32094 by at least 50%. The inhibitory activity can be determined in an assay comprising: (1) preparing a fermented milk product by: (a) inoculating a milk with the Lactobacillus fermentum in a concentration of at least 107 CFU/g and with a starter culture, (b) fermenting until a p H of 4.6 is reached, and (c) solidifying the fermented milk by the addition of agar； (2) generating at least one spot of the P. solitum or the P. brevicompactum on the agar solidified fermented milk with a concentration of 500 spores/spot and incubating the 1 same for 7 days at 25 °C； (3) determining the percent inhibition by determining the largest diameter of the colony formed by growth of the P. solitum or P. brevicompactum and expressing the diameter as percent of the largest diameter formed under the same conditions but in the absence of the Lactobacillus fermentum strain. The invention further relates to compositions comprising the bacterium, methods for producing fermented milk products using the bacterium and the products thus obtained.La presente invención se relaciona con una bacteria de la especie Lactobacillus fermentum que tiene la capacidad de inhibir el crecimiento del hongo Penicillium solitum depositado con el No. de acceso: DSM32093 o el crecimiento del hongo Penicillium brevicompactum depositado con el No. de acceso: DSM32094 por al menos 50%. La actividad inhibidora se puede determinar en un ensayo, que comprende: (1) preparar un producto de leche fermentada por: (a) inocular una leche con la Lactobacillus fermentum en una concentración de al menos 107 UFC/g y con un cultivo iniciador, (b) fermentar hasta que se alcanza un pH de 4.6, y (c) solidificar la leche fermentada median
