L. monocytogenes was isolated from dry skim milk samples, but was not found in whole milk samples. Of 550 isolates, Staphylococcus spp. were identified (60.2%); and also Streptococcus spp. (28%), Listeria spp. (7.8%),and Lactobacillus spp. (4%). This recovery rate could be underestimated as sporal germination and the growth of thermo-resistant Bacillus and Lactobacillus may mask the presence of Listeria spp. in dry milk samples . Several studies suggest that the presence of other microorganisms mask the development of sublethally damaged Listeriaspp. , even when selective media are used to isolate and recover this pathogen.Analysis of variance revealed no significant difference with a 95% confidence interval (p < .05) among the 23 isolates of L.monocytogenes regarding antimicrobial activity (sensitivity to antibiotics).