Australian Iceberg Lettuce
The outer leaves should be checked for infestation. If there are no insects on the outer leaves and after removal of the outer leaves upon visual inspection the core seems clean light green and healthy no further inspection is necessary. If however, there is infestation on the outer leaves, after removal of those leaves the lettuce must be cut in half and visually inspected. If there is no sign of any insects on the inside then no further inspection is required. However, if even one or two insects are found on the inside then the leaves must be individually separated and checked.
OTHER LETTUCE (Cos, Romaine etc), Buok choy
These must have their leaves individually checked. Soaking in vinegar or salt water helps to facilitate removal of insects.