General stages of vegetable checking
Depending on the type of infestation, as well as the type of produce involved, there are different ways of preparing insect-free food. Sometimes careful cleaning is sufficient. Sometimes all that is required is a test. And in some cases, a visual check is adequate. Let us discuss each of these in general terms to give us a broad picture. The applications of these processes will then be spelled out in each individual case.
Cleaning
Where the infestation is easy to wash off, we simply clean the produce. Examples of this are rinsing of peppers and brushing down of celery sticks.
Sometimes detergent is the only way to wash off the infestation. An example of this is cabbage. This is because the insect that often infests cabbage is called a thrip. This tiny insect grips onto the leaf and cannot be washed off. But after soaking the leaves for a few minutes in very soapy water, the leaves become slippery and the thrips lose their grip.
This system, however, is not effective for all insects. Aphids (greenfly) grip leaves with their elongated mouths, so they will not wash off in soapy water.
However, you can wipe them off by sponging both sides of a leaf using a soft, very soapy, sponge.
Accordingly, this method is suitable for lettuce.
Very Important: Cleaning (as opposed to checking or testing) may be done by a non-Jew under your careful and constant supervision. But you need to be aware, that you can only allow the non-Jewish staff to help you if you are standing over them watching them clean the produce correctly. If you have left the room, they may not continue. You need to ensure the method is followed through 100% accurately. Be aware that if 1 insect is left behind by the staff, you are ultimately responsible.
Checking
Where it is possible to visually detect all infestation, we very carefully check the produce visually with the aid of strong lighting. Examples of this are lettuce, baby spinach, and butter beans.
Where aphids are the problem, you must soak the leaves in a soap-water solution, before doing a visual check. This irritates the aphids and often causes them to release their grip from the leaves.
Testing
Sometimes we do not examine the produce at all. Instead, we shake the produce over a surface and scan that surface for infestation. If this reveals infestation, more intense methods of cleaning will be necessary or we do not use the produce at all. This technique is used where the shape of the produce makes it impossible to visually detect infestation and to clean sufficiently well. Examples of this are: flat leaf parsley and some other fresh herbs.