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Veterinarian Explains Maximum Residue Limits

Article-Veterinarian Explains Maximum Residue Limits

Japan imposed maximum residue limits (MRLs) on May 29 for agricultural chemicals, antibiotics and feed additives for imported meat and meat products.

James McKean, Iowa State University Extension swine veterinarian, explains there are similarities and differences between residue monitoring programs in the United States and Japan.

“There are some differences between withdrawal times in the United States and Japan based on the new MRLs, but under most conditions, strict observance of the U.S. withdrawal times also will meet the Japanese MRLs.

“However, there are systematic differences. U.S. MRLs are based on ‘target’ tissue levels, like in the kidney, liver, muscle and fat, while Japan has established MRLs for many tissues and for processed meats. Japan is more likely to specifically test observed injection sites for residues than the United States, which would require a longer withdrawal time for various products,” says McKean.

The new MRLs apply to all food species, including all fresh, frozen and processed products, and by-products imported into Japan. The requirements also apply to domestic Japanese products.

McKean warns a lot is at stake if violations occur.

“On imported products, a first violation found within a one-year period may trigger a 50% inspection of all shipments from that species, country and/or production type,” he says.

“A second violation may cause 100% inspection and increased testing. Also, the product is held until results are known, and importers may be required to pay for the testing and costs of holding the products until cleared. These consequences make finding even one violation an issue for all producers,” stresses McKean.

The National Pork Board provides details for producers on a special section of their Web site. This Pork Checkoff-funded site is found at It features information supplied by pharmaceutical manufacturers for U.S. and Japanese MRLs and withdrawal times.