Kashrut Instructions (Courtesy of OU Kosher)
Aphids, thrips and other insects may often be found on the leaves and stems of fresh herbs such as chives, basil, cilantro, dill, mint, oregano, parsley, rosemary, sage, and thyme. Insects tend to nestle in the crevices between the leaves and branches of herbs. These insects can curl up and stick to the leaf once they come in contact with water.
Recommendation for home preparation: In order to determine if a particular bunch of herbs is infested prior to washing, bang it several times over a white cloth. This is most important when checking oregano, rosemary, sage and thyme. If only one or two insects are found proceed with the steps below. If three or more insects are detected in a particular bunch of herbs it should not be used.
Inspection: Soak herbs in a solution of cold water and vegetable wash. The proper amount of vegetable wash has been added when some bubbles are observed in the water. (In the absence of vegetable wash, several drops of concentrated unscented liquid detergent may be used. However, for health reasons, care must be taken to thoroughly rinse off the soapy solution.)
• Agitate the herbs in the soapy water, in order to loosen the sticking excretion of the bugs.
• Using a heavy stream of water, thoroughly wash off the soap and other foreign matter from the herbs.
• Check both sides of each leaf under direct light.
• If one or two insects are found, rewash the herbs.
• If any insects are found after repeating the agitation process twice, the entire bunch must be discarded.
Please Note: Curly leaf parsley is very difficult to check. It is therefore recommended that only flat leaf parsley be used.