FDA analyzes antibiotic residues in distillers grainsPrint
Source: Marla Luther, PhD, Center for Veterinary Medicine, U.S. Food & Drug Administration (FDA)
Did you know antibiotics are used in commercial fuel ethanol production facilities to control bacterial contamination? The FDA’s Center for Veterinary Medicine (CVM) recently reported on a study of antibiotic residues in ethanol co-products, primary distiller’s grains, which are used as animal feed ingredients.
The Division of Animal Feeds within CVM issued a field assignment during fiscal year 2010 to survey distiller’s products for antimicrobial residues. Samples were collected for informational purposes in order to learn more about the antibiotics used during the production of distillers products and to determine the antibiotic levels in these distillers products. Due to the interest in this area, CVM is providing this summary of the sampling results.
The assignment was issued under the FDA Feed Contaminants Program and requested that 60 samples be collected and analyzed for antibiotics. A total of 46 samples were collected by FDA investigators and these samples were sent to FDA laboratories for analysis. These 46 samples consisted of 18 domestic-import samples (samples were in domestic commerce in the U.S. when collected, but the country of origin was outside the U.S.) and 28 domestic samples (samples were in domestic commerce in the U.S. when collected and the country of origin was the U.S.).
FDA laboratories analyzed 46 samples for residues of up to 12 antibiotics. FDA found four samples had quantifiable levels of antibiotic residues. Of the four positive samples, three were domestic samples; one was from a Canadian import.
The results of the three positive domestic samples are detailed below. Virginiamycin M1 was detected at ~0.16 mg/kg (parts per million or ppm) on a dry weight basis in one sample. Erythromycin was detected at ~0.58 ppm on a dry weight basis in another sample. The final positive domestic sample contained virginiamycin M1 at ~0.15 ppm on a dry weight basis and penicillin G at ~0.24 ppm on a dry weight basis. Although the amount of penicillin found (0.24 ppm) is lower than the LOQ for penicillin, the laboratory was able to accurately quantify this sample for penicillin below 1 ppm.
The positive domestic import sample was from Canada and ~0.18 ppm of virginiamycin M1 was detected by the FDA laboratory on a dry weight basis. This finding was not confirmed by CVM/FDA scientists because the analytical worksheets were not available.
The sampling assignment results are providing FDA with a better idea of the extent and level of antibiotics in distillers products. CVM will take this information into consideration as it develops a policy for antibiotic residues in distillers products. Since the primary objective of this assignment was to collect data on antibiotic residues in distillers products to support policy development, CVM does not anticipate regulatory follow-up.