Horticulturally mature broccoli (Brassica oleraceae
L. var botris), and crisphead (Iceberg) and
green leaf lettuce (Lactuca satia L.) were obtained
from commercial sources and stored at
0° C until used within a few days. Broccoli florets
(ca. 5 cm long) were cut from the stalks. Fully
expanded leaves were chosen from the middle of
the heads of lettuce, eliminating the damaged
outer leaves and immature inner leaves. The
leaves were cut into 2×2 cm pieces, washed twice
in tap water, and spun dry. About 200 g of
broccoli florets or lettuce leaf pieces were put into
4-l glass jars, and held at 15° C for 3 days (green
leaf lettuce), 4 days (crisphead lettuce), or 7 or 9
days (broccoli). The higher than recommended
storage temperature (i.e. 0° C) was used to
shorten the storage period