Thank you for your inquiry.
Just so that our readers may conveniently know the response to the previous entry on the effect of freezing on milk allergens, I have copied the response given by Dr. Anna Nowak-Wegrzyn to the question below.
Response from Dr. Nowak-Wegrzyn: "High temperature has a profound effect on whey proteins in cow's milk such as beta-lactoglobulin and alpha-lactalbumin that generally lose their allergenicity with high temperature. Freezing usually conserves protein structure and function, however there might some alteration of a minor specific allergenic epitope that is relevant for an uncommon patient. This might explain why this child tolerated frozen breast milk but not fresh breast milk, assuming that the mother eats dairy products in her diet."
I have not been able to find anything new in the literature in regards to this issue since Dr. Nowak-Wegrzyn’s response, and thus there is nothing additional to add.
As you can see from Dr. Nowak-Wegrzyn’s quote noted above, freezing does not in general alter protein structure and function. But she does state that there may be minor specific allergenic epitopes that could be altered. This response is certainly consistent with the tack you took by telling your patient’s mother that it was “probably not” without risk to allow the infant to ingest frozen breast-milk that contained cow’s milk antigens. But the “probably” is the operative word, and the only certain way to answer the question is to do a feeding trial.
Thank you again for your inquiry and we hope this response is helpful to you.
Phil Lieberman, M.D.