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U.S. Department of Health and Human Services

Animal & Veterinary

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CVM Scientists Develop Nitrofuran Residue Detection Method for Shrimp

FDA Veterinarian Newsletter July/August 2005 Volume XX, No IV

Center for Veterinary Medicine (CVM) scientists have developed a method for detecting residues of nitrofurans in shrimp and have created a video to show the process to other scientists so they can check imported foods to detect residues of the illegal drugs.

Nitrofurans are broad spectrum antibiotics that have been used in a variety of species, including chicken, turkey, pigs, cattle, shrimp, and fish. However, the Food and Drug Administration withdrew approval for use of nitrofurans (furazolidone and nitrofurazones) as antiprotozoals in poultry and swine in 1991, because the drugs are considered to be mutagenic and carcinogenic. In 2002, FDA also withdrew approval for remaining topical uses in food-producing animals. FDA has no approved uses of nitrofurans in food-producing -animals.

However, nitrofurans are used in other countries. The European Union detected nitrofurans in imported shrimp in 2002, so regulators in the United States developed a method to detect that use.

Nitrofurans are quickly metabolized in animals, so residue detection methods must be able to spot the drug’s metabolites. Researchers in CVM’s Office of Research, Dr. Pak-Sin Chu and Dr. Mayda Lopez, developed a method for detecting the metabolites in shrimp. It is a modified method based on methods used for land animals. It detects bound residues of nitrofuran drugs, and has a sensitivity of 1 part per billion. The method uses liquid chromatography-tandem mass spectrometry, and was described in an article in an issue of the Journal of Agricultural and Food Chemistry.

CVM has shared the methodology with the Food and Drug Administration’s regulatory enforcement arm—the Office of Regulatory Affairs. A modified version of the methodology can be used in field laboratories, for enforcement actions.

Dr. Chu and Dr. Lopez have developed a written Standard Operating Procedure describing the method. They also created a video that fully describes the steps in the process. The audience for the video is primarily analytical chemists and regulatory -scientists.

The 33-minute video includes seven sections: introduction, sample pre-washing, hydrolysis and derivatization, sample cleanup, liquid chromatography-tandem mass spectrometry, quantitation, and confirmation. It shows Dr. Lopez performing the steps of the method.

“Lab techniques that are hard to accurately capture with words can be effectively illustrated with the power of visual presentation,” Dr. Chu said. The video is a cost-effective option for making such presentations to several labs, he added.