Chemical Residue Laboratory
Overview
The Bureau of Chemical Residue Laboratories in the Division of Food Safety, Florida Department of Agriculture and Consumer Services (FDACS), is responsible for the chemical analysis of poisonous or deleterious chemical residues remaining in or on human food produced or marketed in Florida, as well as for the regulatory enforcement of federal pesticide and antibiotic residue tolerances and guidelines adopted by the State for raw agricultural produce.
Background
Food safety relating to pesticide residues first became a public concern in the late 1950’s. In response to that public concern, the Commissioner of Agriculture ordered a mobile laboratory constructed to analyze pesticide residues in food. In 1959, this mobile laboratory unit was completely equipped and manned by two specially trained chemists. Inspectors were also trained and assigned to this mobile laboratory program. The monitoring program began in early 1960 and the laboratory stayed in central and south Florida, where most of the fresh vegetables were grown. Although the number of pesticides and vegetable samples analyzed during the first few years was very limited, the violation rates (the percent of samples analyzed in which the amount of pesticide residue exceeds established tolerances) were between 9% and 10%.
In 1964 several gas chromatographs were purchased and the analytical capabilities were extended to all human foods with an extended list of pesticides analyzed. Over the years, the analytical capabilities of our Laboratory have expanded even further to accommodate an increasing number of classes and types of pesticides. Currently, the laboratory is headquartered in Tallahassee. The laboratories are staffed with a highly knowledgeable and experienced technical staff and are equipped with state-of-the-art analytical instrumentation for chemical residue and contaminant analyses.
In 2002 the laboratory began to analyze antibiotic residues in seafood and honey. The increased use of antibiotics in aquaculture and animal industry has resulted in violative detections in imported shrimp, crab, basa and honey. Analysis of antibiotic residues requires sophisticated techniques which detect the analyte at ppb levels.
Analytical Coverage
Many pesticides are registered by the State of Florida and the U. S. Environmental Protection Agency (EPA) for use in food production. Each registration specifies the crops to which that pesticide may be applied. Foods harvested with applications of registered pesticides following label directions may, or may not, contain pesticide residues. However, the laboratory must have the analytical capabilities to detect as many pesticides as possible.
In order to complete the analyses in a reasonable amount of time, and to be able to detect literally hundreds of chemicals, multi-residue analytical procedures are used whenever applicable. Each routine sample is analyzed using multi-residue screen procedures. These procedures combined can detect over 150 pesticides and metabolites. Other specific multi-residue analyses are performed as needed. In situations where the pesticide cannot be analyzed by a multi-residue procedure, individual residue procedures are utilized.
Each year the Chemical Residue Laboratory performs more than 250,000 analyses on 3,000 samples. Approximately 50% of the food samples analyzed did not contain any detectable pesticide residues. The majority of detected residues are below established tolerances and guidelines. The average violation rate during the past decade has been approximately 2%; 70% of these violations occurred because no tolerances were established for the pesticide/crop combination. The decrease in pesticide residue violations, compared to violations in the 1960’s, has been achieved through the Department’s rigorous regulatory and extensive pesticide application education programs.
State Pesticide Residue Regulatory Program
Sample Selection - Fruits and Vegetables
Samples for the Florida pesticide regulatory monitoring program are collected from fields, packing houses, central warehouses, wholesalers, retailers and importing facilities. Depending on the time of the year, samples to be tested are either Florida-grown or shipped in from other states or foreign countries. Samples are categorized into four categories: 1) Core commodities. Approximately 80% of samples are chosen from this group. This category contains products that are consumed more frequently, are grown in Florida or have been found to contain violative residues in past years. 2) Auxiliary Commodities. Approximately 10% of samples are chosen from this group. This category contains all other products, which are not specifically listed as Core. 3) Discretionary samples. Approximately 7% of samples are collected by Chemical Residue field inspectors at their discretion based on knowledge of current pesticide use practices and anticipated problems. Low Volume/Low Consumption products such as herbs should comprise only 1% of total samples collected as discretionary. 4) Investigatory samples. Approximately 3% of samples collected are in response to a known residue violation found either in a regulatory sample analyzed in Florida, by another state or by FDA.
FDACS-Chemical Residue Laboratory field inspectors survey fruit and vegetable fields and interview farmers to find out the types of crops and amount to be grown, planting time, and estimate the harvesting time. When possible the inspectors will inquire which pesticides are to be used on the crop and report the information to headquarters and the Laboratory. The headquarters office also keeps in touch with the U. S. Food and Drug Administration and other state regulatory agencies to obtain regulatory information on food shipped into Florida.
Regulatory Actions
The time between sample arrival and analytical results is extremely critical. In order for the program to be effective, food products containing chemical residues in excess of the official tolerances or guidelines are intercepted in the trade channels. Sample analyses, therefore, must be performed in a timely manner.
Laboratory standard operating procedure (SOP) requires confirmation procedure(s) to be performed on all positive pesticide residue findings. When a sample is found to contain a pesticide residue exceeding the established tolerance, or a residue, which has no tolerance for that commodity, the lot is placed under stop-sale/stop-harvest order. A confirmation sample from the same lot is collected and analyzed. Then, upon completion of confirmation of violation, contaminated lots are destroyed.
Special Chemical Residue Surveys
In response to food safety issues that are identified at the national or international level, the laboratory develops methods for selected analytes and commodities. These special surveys are targeted to particular problem areas. Samples may be collected at a variety of locations depending on the particular problem.
USDA Pesticide Data Program (PDP)
In May 1991, the Chemical Residue Laboratory along with the United States Department of Agriculture (USDA) and five other states implemented the Pesticide Data Program (PDP), a federally funded grant program designed to assess statistically-based pesticide residues in fresh fruits and vegetables. The PDP is strictly a monitoring program designed to provide information on pesticide residues present in randomly selected samples taken near the point of consumption. This data along with food intake data from the USDA, gives a clearer picture of dietary exposure. This enables the Environmental Protection Agency (EPA) to assess the continuing appropriateness of pesticide residue tolerance levels. The PDP also allows EPA to make necessary risk assessments and regulatory decisions based on actual exposure data. PDP is now a critical component of the Food Quality Protection Act (FQPA) of 1996. The pesticide residue data generated by this program are used to better inform the public of the safety of the nation’s food supply. As of July 2003, nine states are participating in the Pesticide Data Program.
Staffing
The Chemical Residue Section consists of laboratories in Tallahassee and field inspection. Twenty-four professional chemists and two laboratory technicians staff the laboratories. Of these twenty-four chemists, two chemists are staffed as Quality Assurance Personnel. Four chemists are staffed as Laboratory Management and eighteen are laboratory analysts. Six field inspectors are situated throughout the state in six geographic districts. All professional chemists are required to have a B.S. degree in Chemistry or a closely related natural science, and undergo extensive in-house training. Laboratory personnel participate in national and international organizations and update skills frequently through attendance at training courses and professional conferences.
If you have any questions about the Chemical Residue Laboratory, please contact:
Jo Marie Cook, Bureau Chief
3125 Conner Boulevard, Lab # 3
Tallahassee, FL 32399-1650
Phone: (850) 617 - 7500
FAX: (850) 617 - 9110
