★ Heat stability of biotech proteins is part of the weight of evidence for potential allergenicity. ★ Heat stability is evaluated by monitoring loss of functional activity at various temperatures. ★ The temperatures that are selected reflect normal processing conditions of that crop. ★ Applying immunodetection methods in this evaluation does not inform the safety assessment.
Thermal stability has been reported as a shared characteristic among some of the major food allergens and appears to have originated from the observation that some cooked foods retain their ability to cause allergic reactions by Immunoglobulin E (IgE) binding and the subsequent cascade of events that mediate allergic reactions. Based on this observation, the thermal stability of novel food proteins, like those in transgenic crops, is considered correlative with allergenic risk and has prompted requests from some regulatory agencies for additional testing to address safety concerns. Because human testing and serum IgE screening are not feasible nor are they necessarily useful for evaluating the thermal stability of a novel food protein, a protein function assay is often used to assess the thermal stability in the context of an allergenicity risk assessment. Some regulatory authorities also require immunodetection using polyclonal IgG antibodies and gel based methods. Here we review why heat stability as measured by these functional and immunodetection assays does not correlate with allergenicity and provides no useful safety information in assessing the allergenic potential of novel food proteins.