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Allergen control plans are increasingly used by the food industry to prevent allergen cross-contact and validation of these plans involves methods to detect allergen protein residues. A commonly used rapid allergen detection method is lateral flow devices, although research about their validation is lacking. The objective of this research was to investigate lateral flow devices, their specificity and sensitivity to milk proteins and milk-derived ingredients, swabbing conditions, and applications in cleaning validation.
Several lateral flow devices advertised to detect total milk did not detect whey proteins or whey-derived ingredients. The overload level of the kits was highly variable (ranging from 100-10,000 ppm milk protein), stressing the necessity of validating each kit for its intended purpose.
Milk soils were produced on stainless steel panels in order to assess swabbing conditions. There was essentially no difference in sensitivity achieved from using the swab provided by a kit as compared to a common swab, but certain swabs were better suited to scraping soils rather than absorbing liquid soils. The milk soils that were dried at high heat had a lower recovery than unheated or low heat soils.
Concentration dependent interferences with lateral flow devices and general protein tests were found with caustic cleaning solutions and oxidizing sanitizers, respectively. Four food-processing surfaces: 316 grade stainless steel, HDPE, Nylon 6/6, and Delrin, were soiled with milk and cleaned with each cleaning solution of a typical CIP system separately and then sequentially. When used separately, a commercial caustic solution was observed to outperform a commodity caustic solution. The acidic and sanitizing solutions did not contribute to milk soil removal. The stainless steel surface was most easily cleaned. The lateral flow devices were able to detect milk soils with similar frequency, while the general protein kit had a lower sensitivity. An enhanced visualization method which employed protein staining and scanning of the soils was used, but more development of this method is necessary prior to further use.
Advisors: Joseph L. Baumert and Stephen L. Taylor