Pure Encapsulations, Inc. Has Issued Allergy Alert On Undeclared Egg Allergen In Prenatal Nutrients. Pure Encapsulations of Sudbury, Massachusetts is voluntarily recalling PreNatal Nutrients lot number 3560111, because it may contain undeclared egg allergen. People who have an allergy or severe sensitivity to egg run the risk of serious or life-threatening allergic reaction if they consume these products.