h. RVB cultures were streaked onto XLD plates and
incubated at 37 C for 24 h. Colonies presumptive for S. enterica
were stabbed into and streaked onto triple sugar iron agar (TSI;
BBL/Difco) slants using sterile needles, incubated at 37 C for 24 h,
and examined for the presence of S. enterica. The detection limit for
E. coli O157:H7 and S. enterica by direct plating was 1.0 log CFU/g
(10 CFU/g) and the detection limit by enrichment was 0.7 log CFU/
g (1 CFU/5 g). To determine the germination rate, pak choi seeds
(n ¼ 100) with or without sequential treatments of ClO2, drying,
and dry heat were placed on cheesecloth in a sprout cultivator
containing sterile DW and incubated at 25 C for 5 days. The
number of seeds that germinated out of 100 seeds tested was
counted and expressed as a percentage.