A number of Mashgichim experimented with Brussel Sprouts and asparagus for a year. They found that wherever they grew and at whichever season Brussel Sprouts were highly infested. Only Brussel Sprouts grown in an insect free environment should be used. On the other hand, white asparagus are very clean and may be used without checking. Green asparagus may have some infestation. The following method should be used for small batches of asparagus. If this method was used on 15 spears and no insects were found, the remainder of that lot may be used without further checking.
Remove Triangular side leaves and use the thrip cloth method on the tops.
Thrip Cloth Method:
- Wash produce well.
- Prepare a basin with water and a safe dishwasher detergent solution. You may also use kosher vegi-wash at three times the recommended strength. Vegi-wash is available through Amazon. (Mashgichim like Dawn brand liquid detergent because it is less likely to spoil the taste of the vegetables.) The water should feel slippery.
- Agitate the produce in the solution for 15 seconds.
- Remove the produce from the basin and shake off excess water over the basin.
- Pour water through the thrip cloth.
- Check the thrip cloth over a light box for any insects. If your overhead lighting is just as effective you may use that. Use a needle to move any suspicious debris to check if it is an insect or worm.
- If any insects are found, repeat steps 1-6.
The Star-K has a convenient vegetable checking guide for consumers available here. (The procedures for industrial checking are somewhat different.)