Normally, the use of the “initial objective sign” would lead to threshold values that are “protective” in relation to the overall risk to food allergic consumers. However, it should be noted that severe reactions have been reported as the initial objective sign in some cases. For example, Perry et al. (2004) reported that almost 30% of intial reactions were severe and stated that “reaction severity did not increase as the amount of challenge food ingested increased.” Likewise, the only severe reaction observed by Hourihane et al. (1997a) in a population of 100 patients occurred at the lowest dose tested. However, considering that the use of the “initial objective sign” does appear to be generally protective, and that such data would be used in conjunction with appropriate uncertainty factors, it may not be necessary to differentiate among “mild,” “serious,” or “life- threatening” signs when establishing a safety assessment-based threshold from existing clinical data.
c. Analytical Methods for Food Allergens. The criteria used to evaluate the available analytical methods for the major food allergens are shown in Table IV-3 and are applied in Appendix 1.
Table IV-3. Specific Criteria for Evaluating Analytical Methods for Food Allergens
Criteria 1. Has the method been validated?
Is the method sufficiently sensitive?
Does the method detect both raw and
processed food allergens?
4. Has the species specificity of the method been determined? 5. Has the protein target (or targets) for the method been determined?
6. Is the method practical?
Comments Methods that have been validated (such as by AOAC) are preferred. Alternatively, the sensitivity, precision, and reproducibility of the method have been demonstrated in a peer-reviewed publication. The limit of detection and the limit of quantitation should be below the levels that appear to cause biological reactions. The relevant processing methods (e.g., boiling, roasting, retorting) will depend on the food. This is most relevant to methods for allergens such as fish and tree nuts. This is relevant to determining whether the assay detects specific allergenic proteins or general biomarkers. The method should use common laboratory equipment and supplies.
The response of sensitive consumers to exposure to an allergen is dependent on the levels of the allergen in the food and the amount of food consumed, two factors for which there is both variability and uncertainty. The levels of allergen in foods may not be known for a number of reasons, particularly when the presence of the allergen is the result of cross- contact. Even in highly controlled clinical studies, questions regarding the level of allergen arise due to differences in the methods used to process and prepare the test material, incomplete characterization of this material, variability in allergen levels among
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