Performance Evaluation of Protein Wiping Method to Prevent Cross-contact with Eight Specified Allergenic Food Ingredients

The detection sensitivity of the protein wiping method based on BCA assay was evaluated for specified allergenic food ingredients. The detection sensitivity was measured when BSA samples and eight specified allergenic food ingredients (shrimp powder, crab powder, walnut paste, wheat flour, buckwheat flour, liquid egg, milk, and peanut powder) were applied to 25 cm² stainless steel surfaces, dried, and subsequently wiped off with a swab. The visually detectable limit was determined to be 2-2.25 μg using a BSA solution as the standard, with an absorbance of approximately 0.3 at 562 nm. Test areas with low (2.5 μg/25 cm²), medium (5.0 μg/25 cm²), and high (7.5 μg/25 cm²) contamination levels were prepared, and recovery tests were performed using the protein wiping method. The measurement error was within ±0.03. Moreover, the recovery rate from swabs was observed as 78.2-94.4%. Recovery tests for eight specified allergenic food ingredients showed the ability to detect the ingredients when >10 μg of material was applied to the test surface. This study suggested that the protein wiping method is useful for cleanliness control to prevent cross-contact of allergens in the food manufacturing environment.