Tilmicosin is a veterinary antibiotic sold around the world under numerous brand names. It’s used to treat cattle and sheep, respectively, for bovine and ovine respiratory diseases. FDA WarningThe U.S. Food and Drug Administration (FDA) has established a safe (or tolerance) level of 0.1 parts per million (ppm) for residues of the drug in muscle tissue and 1.2 ppm in liver tissues. A beef cow offered for sale as as animal for slaughter by cattleman Silas C. Lawhorn of Bedford, VA, last Feb. 8, 2014, was found in testing conducted on Feb. 11 with residues of the antibiotic resulting in 2.914 ppm in the muscle tissue and 19.994 ppm in the liver tissue. That means the Virginia animal had 16 to 30 times the amount of Tilmicosin as residue in its tissues than FDA considers tolerable or safe. The testing was conducted by USDA’s Food Safety and Inspection Service and resulted in Lawhorn getting a warning letter from FDA about the findings and its own investigation, which had been ongoing since last Dec. 16-19. The letter stated, in part: “Our investigation found the following violations: • Failure to inquire about the medication status of the animal(s) that you purchase and deliver for sale. You do not inquire about the medication status of purchased animals. • Administration of veterinary prescription drugs was performed without the lawful written or oral order of a licensed veterinarian. You administered the new animal drug (b)(4)(tilmicosin, (b)(4)) to your angus beef cow identified with ear tag # (b)(4) for pneumonia in early December, 2014 without a lawful written or oral order of a licensed veterinarian. • You lack an adequate inventory system for determining the quantities of drugs used to medicate your livestock. You have no drug inventory system at your firm.” The March 12 warning states that the letter should not be read as an all-inclusive list of violations. It asks for a response to FDA’s concerns within 15 working days. The only other food-related FDA warning letter released this past week went to the Yamashin Company Ltd. in Japan and concerned labeling issues involving its soy sauce.