**5. Conclusions**

Due to the technological limitations, the current approach to PAL relies on a nonanalytic-based risk assessment. As in our study the sensitivity of MS proteomic largely exceeding the limits recommended by the VITAL grid, we conclude that an accurate quantification of tiny amounts of protein in complex foods, in combination with population clinical studies, deserves the potential to establish exact reference doses below which no reactions could be exerted even in the most sensitive individuals.

When proteomic determinations show that the controls carried out at the level of the production and distribution chain are sufficient to avoid this risk for the tested product, the clinician may be authorized to exempt children allergic to milk and egg from observing PAL.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/ 10.3390/nu13124540/s1, Table S1: Doses of biscuit administered to children in the experimental challenge, Table S2: Correspondence amongst Magretti doses tested on patients by OFC and SPT and samples subjected to proteomic experiments, Table S3: QTrap 6500+ MS compound parameters of milk α-S1-Casein and egg albumin detected ions, Table S4: QSight 220 MS compound parameters of milk α-S1-Casein and egg albumin detected ions, Table S5: Demographic data of the patients, Table S6: Clinical characteristics of the patients.

**Author Contributions:** Conceptualization, V.F., A.F. and L.P.; methodology, V.F., V.M., L.M., R.P., A.F. and L.P.; validation, L.M., A.F. and L.P.; formal analysis, R.V.; investigation, V.F., V.M., L.M., P.V., M.M., S.L.M., R.P., L.D., V.C., G.B. and C.R.; resources, L.M., A.F. and L.P.; writing—original draft preparation, V.F., M.M. and A.F.; writing—review and editing, V.M., L.M., R.P. and S.A.; visualization, V.M.; supervision, A.F and L.P.; project administration, A.F.; funding acquisition, A.F. and L.P. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Galbusera S.p.A. It also was supported by a grant of Italian Ministry of Health, Ricerca Corrente 2018, to Lorenza Putignani and Alessandro Fiocchi.

**Institutional Review Board Statement:** The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Institutional Ethics Committee of Bambino Gesù Children's Hospital IRCCS (protocol number 1022\_2015\_OPBG, 10 December 2015).

**Informed Consent Statement:** Written informed consent from either parents or legal representative of children was obtained for the participation to the study.

**Data Availability Statement:** Dataset is available on request.

**Acknowledgments:** We would like to thank P. Dossetto and L. Rieux (Sciex) for helpful advice.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
