Efecto del ácido Clorhídrico y ácido Láctico sobre el desarrollo de treinta cepas de Listeria spp. aisladas de alimentos

listeria monocytogenes is the causative agent of listeriosis in humans, being the ？ready to eat？ foods one of the main transmission ways. the optimun ph for l. monocytogenes to grow was between 6 and 9, tolerating up to ph 4.4. the objetive was to study the in vitro behavior of thirty strains listeria spp. isolated from foods, modifying the ph adding hcl and lactic acid. brain heart broth added with hcl or lactic acid until ph 4.8, 5.2, 5.5, 5.8 and 6 was used. with hcl at ph 4.8 one strain of l. monocytogenes type 1 developed. at ph 5.5, 50% of the strains developed. with lactic acid, at ph 4.8 growth was not observed. at ph 5.8 and 6 with both acids grew most of the listeria analyzed. the lactic acid had a greater inhibitory effect than hcl.