*****FROM ABC NEWS MEDICAL UNIT*****
Hi onry13 and thank you for your question. Here's an answer from David Hauswirth, M.D., Assistant Clinical Professor--Medicine and Pediatrics, The Ohio State University/Nationwide Children's Hospital:
The product in question is made from the shells of walnuts, and likely does not contain any of the nut protein. However, if there is no disclosure from the manufacturer about the process used to gain the shells or how they are treated prior to inclusion in the product, I would suggest anyone who has a known allergy to walnut or is avoiding tree nuts, avoid this product. Most likely, it is safe, however if the company doesn't disclose this, it is always better to err on the side of caution. The only way to know how low the risk is would be to assay the sponge for walnut protein and see if any is detectable. This would need to be done in a lab that is qualified to find low levels of allergic proteins.
The other item to mention is that this is a sponge, and should not be eaten or near food. Just having contact with the sponge is unlikely to transmit enough (if any) protein to cause a reaction in most people. The best course of action would be to talk to the doctor who diagnosed the food allergy about your specific situation and whether or not you should avoid this new material.
NOTE: Top medical experts on allergy answer questions like these on the OnCall+ Allergy: http://abcnews.go.com/Health/Allergies.
*****FROM ABC NEWS MEDICAL UNIT*****