2.6. Populations of E. coli O157:H7 and S. enterica after sprouting
decontaminated pak choi seeds
To estimate the microbiological risks of sprouts produced from
inoculated pak choi seeds after sequential treatments of ClO2,
drying, and dry heat, populations of E. coli O157:H7 or S. enterica in
the pak choi sprouts were determined. Pak choi seeds (5 g), which
had been inoculated with E. coli O157:H7 or S. enterica and
sequentially treated with water or ClO2 (200 mg/ml for 5 min),
drying (45 C/23% RH for 24 h), and dry heat (80 C/23% RH for 6, 12,
24, or 48 h) as described above, were placed on sterile cheesecloth
in a sprout cultivator containing sterile DW water and cultivated at
25 C for 5 days. Sprouts (5 g) were placed in a Whirl-pak bag
containing 50 ml of TSB and pummelled for 1 min in a stomacher.
Populations of E. coli O157:H7 and S. enterica in homogenates were
determined by spread plating as described above