Each L. innocua strain was cultured independently in 30-mL
Tryptic Soy Broth (Difco) in 50-mL sterile tubes at 37 ◦C (150 rpm)
for 18 h. The cultures were then diluted in Butterfield’s phosphate
buffer (BPB; Applied Research Inst., Newtown, Conn., U.S.A.) as a
mixture.