Checking Vegetables for Insects

Waiter: What would you like for an appetizer?

Customer: Salad, please.

The popularity of fruits, vegetables, and berries has increased in recent years due to positive scientific studies about potential health benefits from antioxidants contained in them. However, some consumers have still hesitated to plunge into the world of health out of fear of possibly consuming insects, which are strictly forbidden by the Torah. Nevertheless, kashrus agencies have responded by providing consumers with guidelines as how to handle produce and ensure that insects are avoided. The task may seem daunting at first, but it’s definitely doable. It is possible to have your veggies and eat them too!

The following are guidelines for some select items. There are manuals and guides available from kashrus agencies that provide a more comprehensive list. Please note there is no one absolute and correct way to check vegetables for bugs. There are numerous acceptable methods that have proven to be effective.

Asparagus, Green

Asparagus is a spear-like vegetable approximately 6–8” long with triangle scales along the sides, culminating with an arrangement of triangular tips.

Thrips are primarily found under the triangle scales and somewhat less frequently in the tips of the asparagus.

Asparagus can be used in the following manner:
1. Shave down the floret at the asparagus tip.
2. Remove the triangle parts along the side of the asparagus. (A potato peeler is recommended.)
3. Wash thoroughly.

When prepared in this manner, special inspection is not necessary.

Asparagus, White

This hard to find and very expensive cousin to green asparagus has neither open florets nor scales for the insects to occupy. Hence, it may be used without any special preparation. However, it should be washed thoroughly before using.

Lettuce, Open Leaf

Bibb, Bok Choy, Boston, Butter Lettuce, Chicory, Chinese Lettuce (Napa), Green Leaf, Red Leaf, Romaine, and Watercress all grow in a similar fashion. As they sprout forth from the ground, the leaves begin to open up like a flower. Toward the end of their growth, they begin to close around the stalk.

The insects most commonly found in open leaf lettuce are small green aphids or thrips. The leaves of the vegetable often camouflage these insects. The open structure of these vegetables allows insects to penetrate the entire head. Often, insects may be found between the innermost layers of leaves of an infested head. Therefore, each leaf must be washed and checked individually. The use of a light box for checking lettuce is extremely helpful.

Please note: Many of these varieties feature curly leaves with many folds in which the insects tend to hide. We therefore recommend that they be washed and checked with extreme caution.

1. Cut off the lettuce base and separate the leaves from one another.
2. Soak leaves 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 non-scented liquid detergent may be used. However, for health reasons, care must be taken to thoroughly rinse off the soapy solution.)
3. Agitate lettuce leaves in the soapy solution.
4. Spread each leaf, taking care to expose all its curls and crevices. Using a heavy stream of water or a power hose, remove all foreign matter and soap from both sides of each leaf. Alternatively, a vegetable brush may be used on both sides of the leaf.
5. Leaves should be checked over a light box or under strong overhead lighting to verify that the washing procedure has been effective. Pay careful attention to the folds and crevices in the leaf where insects have been known to hold tightly through several washings.

Herbs-Fresh-Household Use

Fresh basil, cilantro, dill, mint, oregano, parsley, rosemary, sage and thyme are often used as spices or garnishing.

Please note: Curly leaf parsley is very difficult to check. It is therefore recommended that only flat leaf parsley be used.

Aphids, thrips and other insects may often be found on the leaves and stems of these herbs. 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: 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.

1. 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 non-scented liquid detergent may be used. However, for health reasons, care must be taken to thoroughly rinse off the soapy solution.)
2. Agitate the herbs in the soapy water, in order to loosen the sticking excretion of the bugs.
3. Using a heavy stream of water, thoroughly wash off the soap and other foreign matter from the herbs.
4. Check both sides of each leaf under a direct light.
5. If one or two insects are found, rewash the herbs.
6. If any insects are found after repeating the agitation process twice, the entire bunch must be discarded.

Please note: When preparing herbs such as cilantro, dill and parsley for soup, they may simply be washed thoroughly and placed in a cooking bag.


Considered by many the most intensely flavored member of the berry family, the raspberry is composed of many connecting drupelets (individual sections of fruit, each with its own seed) surrounding a central core. There are three main varieties — black, golden and red, the latter being the most widely available. Fresh raspberries are typically available from May through November.

Raspberries can be heavily infested with small mites and thrips. These insects can be nestled on the surface of the berry as well as inside the open cavity of the raspberry. Occasionally, small worms may be found in the cavity of the berry. Note that tiny, dark-colored, leaf-like or seed-like protrusions in the berry’s cavity may appear similar to insects, making the true insects difficult to discern.

Due to the very delicate nature of raspberries, they cannot be placed in water nor may they be extensively handled. Therefore, we recommend the following procedure as the most practical and effective way of checking raspberries:

1. Stretch a white cloth or sheet of white freezer paper over a light box or on a countertop with ample overhead lighting. Raspberries should be dropped one by one onto the white surface. This will dislodge at least some of the insects that may inhabit the berry.
2. If insects are found in a pint of berries, the pint might be infested and may not be used. There is no washing procedure that will guarantee removal of all of the insects.
3. If after dropping the berries no insects are found, the berries should be visually inspected one by one. Pay careful attention to the cavity of the berry where insects often hide.

The above article is based on the OU Guide for Checking Fruits, Vegetables, and Berries-2nd edition.

Rabbi Bistricer is a Rabbinic Coordinator at the Orthodox Union and specializes in, among other things, fruits and vegetables.

OU Kosher Staff