AOAC Guidance on FA Immunoassay Validation (August 2023)

4. Surface Swab Sample Collection 1291 4.1. For dry surfaces, remove test kit specified swab from the packaging and wet with test kit specified 1292 swab solution. A trained operator should swab each test area (10 x 10 cm) in a vertical and 1293 horizontal motion, creating a crosshatch pattern whilst at the same time rotating the swab tip. 1294 4.2. For wet surfaces, remove test kit specified swab from the packaging and swab each test area in a 1295 vertical and horizontal motion, creating a crosshatch pattern whilst at the same time rotating the 1296 swab tip. 1297 5. Interference from cleaning and sanitizing/disinfecting agents 1298 5.1. Cleaning and sanitizing/disinfecting solution studies for an environmental surface claim are 1299 voluntary (case by case required for making claim). Whether or not a method developer has 1300 validated performance in the presence of cleaning or sanitizing chemicals must be stated in the 1301 validation report, validation certificate, and test kit insert. 1302 5.2. If a method developer chooses to include a claim with respect to analysis in the presence of cleaning 1303 or sanitizing/disinfecting chemicals, the following is recommended: 1304 5.2.1. Provide detailed information on the chemicals evaluated and the conditions of use. 1305 5.2.2. Authorized chemicals may vary by regulatory jurisdiction. Examples of relevant chemicals in 1306 the U.S. and EU can be found in 21CFR178.1010 and Biocides Product Regulation (BPR, 1307 Regulation (EU) 528/2012, respectively. 1308 5.2.3. Test sanitizers that are not required to be rinsed off (e.g., those intended for kitchens, 1309 restaurants, food processing and food co-packing, etc.) for interference within the assay. 1310 5.2.4. Detect the presence of the food allergen material in cleaners intended for surface and CIP 1311 treatment as well as sanitizers at the concentration recommended by the manufacturer as 1312 final working solution. If the claimed detection capability is not achievable serial dilutions are 1313 suggested to determine if the CDC can be achieved at prescribed application levels that are 1314 efficacious for cleaning and/or low residual levels in wash water solutions. Report levels tested 1315 and the interferences with accuracy/CDC of the method. 1316 5.2.5. If the target food allergen is not detected in the presence of the chemical(s), additional data 1317 may be required to verify whether the protein maintains its integrity (primary structure) under 1318 the relevant conditions. ELISA or mass spectrometry may be suitable for this purpose, 1319 depending on the specific chemical and use conditions. 1320 6. Storage and shipment of sample . If testing needs to be delayed, stability of the swabs needs to be 1321 assessed. 1322 7. Sample preparation. Follow kit instructions as written.

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