2.4. Lactic acid production and pH reduction ability
The effectiveness of selected LAB on the growth of pathogenic
bacteria was further studied for lactic acid production. Each
selected strain was cultured for 4 8 h at 37
C in MRS broth.
Approximately 10
7
cfu/ml of the selected LAB were inoculated into
40 ml MRS broth. The cultures were incubated for 4 8 h at 37
C, and
aliquots were taken for the measurements of the pH of the media.
The pH was directly measured using a pH meter (420A, Orion,
Hungary). A cell-free solution was obtained by centrifuging (950 0g ,
10 min, and 4
C) the culture broth and used for total acidity to
determine the lactic acid (AOA C , 2 0 0 0).