A method of detecting the contamination of a beef sample by one or more meats selected from the group consisting of pork, lamb, chicken, horse and duck, the method comprising: adding a proteolytic enzyme to the sample to lyse at least a portion of any of the one or more meats other than beef in the sample, into a plurality of peptides; and utilizing liquid chromatography tandem mass spectrometry (LC-MS/MS) to analyze said plurality of peptides to determine whether the one or more meats other than beef is present by monitoring at least one parent-daughter ion pair transition with specified m/z value associated with a specific amino acid sequence selected from the group consisting of: i) SEQ ID NO: 1, m/z value of about 453/581 or 453/480; or SEQ ID NO: 2, m/z value of about 879/777 or 879/981; for pork; ii) SEQ ID NO: 9, m/z value of about 718/1037 or 718/745; SEQ ID NO: 10, m/z value of about 623/523 or 623/823; SEQ ID NO: 11, m/z value of about 515/659 or 515/832; or SEQ ID NO: 12, m/z value of about 431/589 or 431/862 for lamb; iii) SEQ ID NO: 13, m/z value of about 482/213 or 482/750; SEQ ID NO: 14, m/z value of about 768/923 or 768/1037; SEQ ID NO: 15, m/z value of about 789/890 or 789/213; or SEQ ID NO: 16, m/z value of about 684/1136 or 684/1006 for chicken; iv) SEQ ID NO: 17, m/z value of about 677/1122 or 677/992; SEQ ID NO: 18, m/z value of about 977/946 or 977/1442; SEQ ID NO: 19, m/z value of about 550/820 or 550/473; SEQ ID NO: 20, m/z value of about 693/954 or 693/826 for duck; and v) SEQ ID NO: 22, m/z value of about 888/1030 or 888/973; or SEQ ID NO: 23, m/z value of about 818/847 for horse. adding a proteolytic enzyme to the sample to lyse at least a portion of any of the one or more meats other than beef in the sample, into a plurality of peptides; and utilizing liquid chromatography tandem mass spectrometry (LC-MS/MS) to analyze said plurality of peptides to determine whether the one or more meats other than beef is present by monitoring at least one parent-daughter ion pair transition with specified m/z value associated with a specific amino acid sequence selected from the group consisting of: i) SEQ ID NO: 1, m/z value of about 453/581 or 453/480; or SEQ ID NO: 2, m/z value of about 879/777 or 879/981; for pork; ii) SEQ ID NO: 9, m/z value of about 718/1037 or 718/745; SEQ ID NO: 10, m/z value of about 623/523 or 623/823; SEQ ID NO: 11, m/z value of about 515/659 or 515/832; or SEQ ID NO: 12, m/z value of about 431/589 or 431/862 for lamb; iii) SEQ ID NO: 13, m/z value of about 482/213 or 482/750; SEQ ID NO: 14, m/z value of about 768/923 or 768/1037; SEQ ID NO: 15, m/z value of about 789/890 or 789/213; or SEQ ID NO: 16, m/z value of about 684/1136 or 684/1006 for chicken; iv) SEQ ID NO: 17, m/z value of about 677/1122 or 677/992; SEQ ID NO: 18, m/z value of about 977/946 or 977/1442; SEQ ID NO: 19, m/z value of about 550/820 or 550/473; SEQ ID NO: 20, m/z value of about 693/954 or 693/826 for duck; and v) SEQ ID NO: 22, m/z value of about 888/1030 or 888/973; or SEQ ID NO: 23, m/z value of about 818/847 for horse. i) SEQ ID NO: 1, m/z value of about 453/581 or 453/480; or SEQ ID NO: 2, m/z value of about 879/777 or 879/981; for pork; ii) SEQ ID NO: 9, m/z value of about 718/1037 or 718/745; SEQ ID NO: 10, m/z value of about 623/523 or 623/823; SEQ ID NO: 11, m/z value of about 515/659 or 515/832; or SEQ ID NO: 12, m/z value of about 431/589 or 431/862 for lamb; SEQ ID NO: 10, m/z value of about 623/523 or 623/823; SEQ ID NO: 11, m/z value of about 515/659 or 515/832; or SEQ ID NO: 12, m/z value of about 431/589 or 431/862 for lamb; iii) SEQ ID NO: 13, m/z value of about 482/213 or 482/750; SEQ ID NO: 14, m/z value of about 768/923 or 768/1037; SEQ ID NO: 15, m/z value of about 789/890 or 789/213; or SEQ ID NO: 16, m/z value of about 684/1136 or 684/1006 for chicken; SEQ ID NO: 14, m/z value of about 768/923 or 768/1037; SEQ ID NO: 15, m/z value of about 789/890 or 789/213; or SEQ ID NO: 16, m/z value of about 684/1136 or 684/1006 for chicken; iv) SEQ ID NO: 17, m/z value of about 677/1122 or 677/992; SEQ ID NO: 18, m/z value of about 977/946 or 977/1442; SEQ ID NO: 19, m/z value of about 550/820 or 550/473; SEQ ID NO: 20, m/z value of about 693/954 or 693/826 for duck; and SEQ ID NO: 18, m/z value of about 977/946 or 977/1442; SEQ ID NO: 19, m/z value of about 550/820 or 550/473; SEQ ID NO: 20, m/z value of about 693/954 or 693/826 for duck; and v) SEQ ID NO: 22, m/z value of about 888/1030 or 888/973; or SEQ ID NO: 23, m/z value of about 818/847 for horse.