Acid stress was determined following the method
described by G-Alegria et al., 2004 with some
modifications. Lactobacillus strains were prepared as
above and then, inoculated at 10.0 % in MRS broth
( 108 cfu/mL) with the pH adjusted between 2.0 to
9.0 using HCl 37 % (w/v) (Hycel, Jalisco, Mexico),
or NaOH 45 % (w/v) (Hycel, Jalisco, Mexico).
Strains were then incubated at 37 oC for 24 h under
aerobic and static conditions (microaerobiosis) and
final turbidity was measured by spectroscopy at 560
nm.
2.4