Radish seeds were purchased from an online source (Saessakmart,
Seoul, Republic of Korea; www.saessakmart.co.kr). Seeds
(350 g) were soaked in 1050 ml of E. coli O157:H7 suspension for
5 min at room temperature (25 1 C), with gentle agitation. The
inoculumwas decanted and approximately equal amounts of seeds
were placed on three sterile sieves (203 mm diameter by 41 mm
deep; 600 mm pore size) before drying in a laminar-flow biosafety
hood for 2 h at 25 1 C.