Peanut protein appears to be the worst known food allergen in terms of the dose-response relationship. So, if consumer exposure to cry9c protein based upon conservative estimates of the upper-bound exposure levels is well below the threshold dose for peanut protein then allergic reactions to cry9c protein are very unlikely to occur even IF consumers were to become sensitized to cry9c protein. And, corn is not a particularly good source of dietary protein. Corn-based food products typically have very little protein arising from the corn components of the formulation. The best available evidence on the threshold dose needed to provoke allergic sensitization probably comes from examination of evidence arising from allergic sensitization of exclusively breast-fed infants.
Infants are much more likely than adults to become sensitized to food allergens.
It has been observed by many groups that some exclusively breast-fed infants will experience an allergic reaction on their first known, documented exposure to cow's milk, eggs, or peanuts. Presumably, these infants are sensitized through exposure to milk, egg, or peanut protein ingested by the mother and passed through to the breast milk in rather low doses. However, surreptitious or adventitious exposures could certainly have occurred in these infants during the months of breast-feeding prior to the introduction of solid foods, so this information must be viewed with some skepticism. No information exists to my knowledge on peanut protein levels in breast milk. The levels of lactoglobulin or ovalbumin in breast milk are extremely variable from one woman to another.