Bacterial strains and growth conditions
Lactobacillus casei Zhang (provided by Inner Mongolia
Agricultural University Key Laboratory of Dairy Biotechnology and
Engineering, Inner Mongolia, China) was grown in De Man, Rogosa, and
Sharpe (MRS) broth (Solarbio Life Science, Beijing, China) at 37℃ under
microaerophilic conditions. The isolate of E. coli ATCC 25922
(China General Microbiological Culture Collection Center, Beijing,
China) was incubated in Tryptone Soya Broth (TSB, Solarbio Life Science,
Beijing, China) at 37℃. For all treatments, E. coli and LCZ were
plated on Tryptose Soya Agar (TSA, Solarbio Life Science, Beijing,
China) and MRS agar (Solarbio Life
Science, Beijing, China), respectively, after serial dilution and
quantified by determination of colony-forming units (CFU).