(d) When tomatoes roll on dirty belts.
(e) During transit in slackly packed containers. Slackly packed
containers permit the individual items to rub against each other or against the container
(4) Puncturing. Puncturing is not a serious problem with most vegetables
because the main contributor to puncture, the stem, is detached during harvest.
However, punctures are sometimes sustained by cucumbers, eggplants, and some
packs of tomatoes because their stems accidentally or unintentionally remain attached.
(5) Tearing. Tears are sustained by leafy vegetables and, because of the
tissue exposed, contribute to rapid dehydration, discoloration, or decay of the affected
FREEZE INJURY OF FF&V
a. General. Freeze injury is exposure of the product to a temperature below the
freezing point which results in formation of ice crystals and tissue injury. The extent of
freeze injury will vary with the item, length of exposure, and temperature to which the
product is exposed.
b. Loss of Color. A loss of color indicates freeze injury. Loss of color usually
results in a glassy or transparent appearance.
c. Texture. Textural changes include softening and a water-soaked
appearance. Usually, the outer layers of the product will peel. In some cases, the
texture will be dry or parchment-like.
d. Appearance. Freezing injures vegetables and melons because ice crystals
form in the cells and then rupture the cell walls. The damaged or dead cells lose their
resistance to dehydration and to microbial infections. Further, freeze-damaged tissue
loses its normal rigidity and becomes mushy upon thawing, leading to the water-soaked
appearance commonly associated with thawed vegetables.
e. Off-Odors. Freezing also may lead to development of strong off-odors upon
cooking the damaged vegetable. Broccoli is a serious offender because almost
unnoticeable freeze injury to broccoli yields a very objectionable odor.
f. Level of Resistance to Freeze Injury. Figure 5-3 lists some vegetables
according to their susceptibility to freeze injury. Unfortunately, the type of vegetable
does not necessarily yield a clue to the susceptibility to freeze injury. Among leafy
vegetables, lettuce is very readily injured, whereas cabbage is not. Green beans are
readily damaged; green peas are not.