2.1. Isolation and identification of Lb. plantarum ST71KS
Bacteriocinogenic LAB were isolated from homemade goat feta
cheese samples produced in Belogratchik, Bulgaria. Twenty-five
grams of each cheese were homogenized with 225 mL of saline
solution [0.85% (m/v) NaCl] in a Stomacher (Laboratory Blender
Stomacher 400, Seward, England). Serial decimal dilutions were
prepared in sterile saline solution and aliquots plated on MRS
(Difco, BD, Franklin Lakes, NJ, USA) supplemented with 1% (m/v)
agar and incubated for 48 h at 30 C. LAB were enumerated and
plates presenting 15e20 colonies were covered with 10 mL of BHI
(Oxoid, Basingstoke, UK) supplemented with 1% (m/v) agar and
106 CFU/mL of L. monocytogenes 607. Plates were incubated for 24 h
at 37 C and single colonies displaying an inhibition zone were
selected, grown on MRS agar plates for purification, and examined
for colony morphology, microscopic characteristics, production of
catalase and acids.