The issue of food fraud within the meat industry represents a significant challenge with the potential to impact consumer trust, market stability, and public health. The application of traditional methods, such as DNA barcoding, is constrained, particularly in the context of processed foods, where DNA degradation is a common occurrence. This paper introduces the workflow MEATiCode, a comprehensive proteomic LC-MS/MS method for the simultaneous identification of species in meat authentication. A simple sample preparation procedure, comprising extraction, digestion and desalting, was employed, followed by the application of liquid chromatography tandem mass spectrometry (LC-MS/MS). This enabled the differentiation of peptides and proteins between beef, pork, chicken and lamb species with a limit of detection of 0.5%. The method demonstrated high sensitivity and specificity, effectively identifying species-specific peptides and proteins. The study provides a comprehensive account of the development of the MEATiCode database, which incorporates species-specific peptides and integrates this database with Mascot Engine and Proteome Discoverer for the purpose of detecting potential fraud in processed meat products. The application of the MEATiCode method to a range of meat products demonstrated its efficacy, achieving high sensitivity and reliability in the detection of adulteration, even in highly processed or cooked meats.