Detection of milk traces was evaluated in cookies and extruded products model systems (MS) and in commercial products declaring milk presence through either the statement: "Contains…" or precautionary phrases. The aim of the study was to evaluate the performance of two different commercial ELISA kits for this purpose. Six cookies and extruded products model systems and two different batches of eight different types of commercial cookies and two types of extruded products were analyzed. The two different commercial ELISA kits used were R-Biopharm and Veratox-Neogen. In the cookies MS both kits had the same sensitivity while in the extruded products MS, the R-Biopharm kit had higher sensitivity than the Veratox-Neogen one. In the commercial samples only the snack declaring "Contains milk derivatives" showed detectable values of milk proteins. Even though all the remaining products included precautionary phrases on the label, none of them exceeded the quantification limit. The detection and quantification of the allergen will depend on the utilized kit and the treatment to which the ingredients have been submitted. Therefore, the performance of every kit should be studied for every allergen and every particular food matrix. Regarding commercial products, the analysis of more samples coming from different batches would be necessary in order to corroborate these results and verify the correct use of precautionary phrases.