The control of drug and chemical residues in food: the USDA National Residue Program (Proceedings)

The United States has a complex system for controlling chemical residues in meat poultry and egg products, with rigorous processes for approval, sampling and testing, and enforcement. Three principal agencies are involved in the control of residues in meat, poultry, and egg products. The Food Safety and Inspection Service (FSIS), the U.S. Department of Agriculture's public health regulatory agency, works with the Environmental Protection Agency (EPA) and the Department of Health and Human Services' Food and Drug Administration (FDA), to control veterinary drug, pesticide, and environmental contaminant residues in meat, poultry and egg products.

The control of residues is a cooperative effort: EPA and FDA have statutory authority for establishing tolerances (maximum permissible levels) or action levels. FSIS, through the National Residue Program (NRP), tests animal tissues and egg products to verify that tolerances or action levels are not violated. FSIS's primary mission under the NRP is to verify that establishments control animal drug residues, pesticides, environmental contaminants, and any other chemical hazards in and on meat, poultry, and egg products. The NRP also provides for the collection of national data on the occurrence of residues to support risk assessment, enforcement, and educational activities.

FDA establishes tolerances for veterinary drugs and food additives under the statutory authority of the Federal Food, Drug, and Cosmetic Act (FFDCA). These tolerances are published in Title 21 of the Code of Federal Regulations (21 CFR). EPA establishes tolerances for registered pesticides under the statutory authority of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) and FFDCA, as modified by the Food Quality Protection Act (FQPA). These are published in 40 CFR. Maximum permissible levels have also been established for residues that are the result of environmental contamination, such as cancelled pesticides that are no longer approved for use but persist in the environment (e.g., DDT), industrial chemicals (e.g., PCBs), and heavy metals. Tolerances for industrial chemicals and heavy metals are established by FDA and published in 21 CFR. For cancelled pesticides, action levels (similar to tolerances, but less formal) are established by FDA or FSIS, based on recommendations that EPA has published in the Federal Register.

Under the Federal Meat Inspection Act (FMIA), the Poultry Products Inspection Act (PPIA), and the Egg Products Inspection Act (EPIA), FSIS acts to ensure that USDA-inspected meat, poultry and egg products do not contain illegal levels of chemical residues. The cornerstone of FSIS residue prevention activities is the FSIS National Residue Program (NRP), a multi-component analytical testing program for residues in domestic and imported meat, poultry, and egg products. The FSIS NRP, which has been in effect since 1967, provides a variety of sampling plans to prevent residues from entering the food supply, and develops national data on the occurrence of chemical residues to support risk assessment, enforcement and educational activities. The purpose of the residue program is to maintain vigilance for non-permitted residues in food animals.

There are three major aspects of the NRP:

     1. The prevention of illegal chemical residues,

     2. An analytical systematic testing program for the residues in domestic and imported products, and

     3. Verification that slaughter and production establishments are fulfilling their responsibilities under HACCP for preventing violative residues.

The range of chemical compounds evaluated for inclusion in the various NRP testing programs is comprehensive in scope. It includes approved and unapproved pharmaceutical drugs and pesticides known or suspected to be present in food animals in the U.S. and in countries exporting products to the U.S. It also includes any other xenobiotic or naturally occurring compounds that may appear in meat, poultry, and egg products and that may pose a potential human health hazard.

The NRP is designed to provide: (1) a structured process for identifying and evaluating compounds of concern by production class; (2) the capability to analyze for compounds of concern; (3) appropriate regulatory follow-up of reports of violative tissue residues, and (4) collection, statistical analysis, and reporting of the results of these activities.

With the implementation of the Hazard Analysis and Critical Control Points (HACCP) inspection system, another important component of the NRP is to provide verification of residue control in HACCP systems. As part of the HACCP regulation, slaughter and production establishments are required to identify all chemical residue hazards that are reasonably likely to occur and develop systems to guard against them. A vigilant chemical residue prevention program is essential to foster the prudent use of veterinary drugs and pesticides in food animals. In 1999, the NRP was modified to make residue evaluation more consistent with risk assessment principles.

Residue violation information system

When violative residues are detected in food-producing animals submitted for slaughter, FSIS notifies the producer and other parties involved in offering these animals for sale. Product found to contain volatile levels of residues is considered adulterated and is subject to condemnation. If the product has been distributed into commerce, it may be subject to voluntary recall and/or other actions. In addition, FDA and cooperating state agencies may make on-site visits to these firms.

Frequent communication between Agencies (FSIS, FDA, EPA, and states) and divisions of FSIS is vital to the NRP. The Residue Violation Information System (RVIS) database is a nationwide, interagency computer information system designed to share pertinent data for regulatory enforcement on an open and regular basis. The system operates 24 hours a day to provide information on residue violations in livestock and poultry slaughtered in the USA. The RVIS has proven to be an excellent tool for supporting residue control measure in meat and poultry because it allows exchange of information among participating agencies regarding regulatory enforcement.

RVIS is a unique system and a successful example of interagency cooperation and teamwork. It was implemented in 1987, and since that time improvements have been made to increase the capabilities for its use. The goal continues to be to provide reliable, consistent, current and accessible source of information on residue violations.

Residue control: a team effort

An essential aspect of food safety in meat, poultry and egg products is the control of residues that may result from the use of animal drugs and pesticides, or from incidents involving environmental contaminants. The FSIS National Residue Program is an example of interagency cooperation and teamwork between Food and Drug Administration, the Environmental Protection Agency and FSIS. Within FSIS there is extensive teamwork among the following offices and personnel: Office of Public Health and Science, Office of Policy and Program Development, National Information Technology Center, District Offices, Laboratory support (Eastern Lab, Western Lab and Midwestern Lab), and most importantly, the FSIS in-plant personnel who review animals every day, collect and submit the samples. This teamwork is what makes the National Residue Program a success.

Additional information on the USDA Food Safety and Inspection Service National Residue Program can be found on the USDA FSIS website at www.fsis.usda.gov/Science/Chemistry/index.asp#nrp.