Some of the major allergens identified in the FALCPA consist of multiple species (i.e., tree nuts, fish, crustacean shellfish). Because consumers who are sensitive to one species in a group are also likely to be sensitive to other members of the group, the Threshold Working Group concluded that any thresholds established for these allergens should be based on the combined amount of protein from these species present.
f. Processing and Matrix Effects. Most of the food allergens identified in the FALCPA are eaten in a processed form. The existing data show that processing can increase, decrease, modify, or have no affect on allergenicity depending on the allergen, the process, and the matrix involved. A process that modifies the structure of an allergenic protein could reduce allergenicity for one population of susceptible individuals while simultaneously increasing allergenicity for a separate susceptible population.
Most clinical studies are conducted using test materials that have been processed, such as peanut butter prepared from roasted peanuts. Therefore, these studies are likely to mimic actual consumer exposure to the allergen. However, some uncertainty remains because consumers are exposed to food allergens processed in many different ways and in many matrices. It would not be practical to conduct the large number of clinical studies that would be necessary to reduce this uncertainty. Fish appears to be an important exception because raw fish is often used as a test material. Most people eat cooked fish and this should be taken into account when evaluating the results of these studies.
2. Options and Findings There are four general approaches that could be used to establish thresholds for food allergens – analytical methods-based, safety assessment-based, risk assessment-based, and statutorily-derived. Each approach has strengths and weaknesses, and the application of each is limited by the availability of appropriate data. It is likely that there will be significant scientific advances in the near future that will address a number of the limitations identified in this report. The Threshold Working Group was aware of several potentially important studies that are currently in progress, but was unable to fully consider them because the data or analyses were incomplete.
Finding 1. The initial approach selected to establish thresholds for major food allergens, the threshold values, and any uncertainty factors used in establishing the threshold values should be reviewed and reconsidered periodically in light of new scientific knowledge and clinical findings.
a. Analytical Methods-Based Approach. The analytical methods-based approach could be used to establish thresholds if the available data are insufficient to establish thresholds using one of the other approaches. This approach requires that analytical methods be available to detect each major food allergen. Thresholds would be defined by the limits of detection of the available analytical methods, but there would be no relationship between these thresholds and the biological response thresholds. Currently, the lower detection limits for commercially available allergen ELISA or immunoassay test kits are in the range of 0.1 to 1.0 µg protein/g of food, but such kits are not available for all food allergens. Establishing thresholds at levels higher than the lower detection
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