Programs & Services » Chemical Residue Laboratory

Chemical Residue Laboratory

  
The SC Department of Agriculture Chemical Residue Laboratory analyzes fruit and vegetable samples from supermarkets and farmers markets statewide to detect any possible chemical adulterants or pesticide residues that may be present. 
 
To comply with Food Safety Laws, the Department conducts a Market Basket Survey.  This activity involves collecting samples of individual lots of domestically produced and imported foods as close as possible to their point-of-entry into the distribution system.
 
When illegal pesticide residues are found, the Food and Drug Administration (FDA), or for samples grown in South Carolina, the SCDA can impose various sanctions, including seizure of the commodity or injunction. For those samples imported into the United States, shipments will be stopped at the port-of-entry if they are found to contain illegal residues. If there is reason to believe that future lots from a particular foreign grower or geographic region may be in violation during a given season, the FDA can invoke detention without physical examination (automatic detention). In this case, the produce will be detained at the port of entry until analysis is complete.
 
In the United States there are three government agencies that share responsibility for the regulation of pesticides – the Environmental Protection Agency (EPA), the Food Safety Inspection Service of the United States Department of Agriculture (FSIS-USDA), and the Food and Drug Administration (FDA). The EPA registers (i.e. approves) for use and sets pesticide residue tolerances if the use of a particular pesticide may result in residues on food (Reorganization plan No.3, 1970). The EPA relies upon the USDA and FDA for Federal enforcement of food adulteration. The FSIS monitors and enforces tolerances of pesticide residues on meat, poultry, and certain egg products.
 
A residue tolerance is commodity-specific, federally established upper limit to the amount of a chemical residue allowed on the individual food or feed product [i.e. 8 parts per million (ppm) malathion allowed in strawberries]. Tolerances impact food safety by limiting the concentration of a pesticide residue allowed on a commodity and by limiting the type of commodity on which it is allowed. Tolerances are the only tools the EPA has under Federal law to control the quantity of pesticides on the food we consume.
 
To be able to enforce the EPA mandated tolerances, both the FDA and SCDA must know the quantity and the type of pesticide residue present in foodstuffs offered for sale. The Chemical Residue Laboratory performs analysis of foods sold within the state of South Carolina for pesticide residues. This Market Basket Survey concentrates on fresh produce grown in this state, but also includes fresh produce from other states and foreign countries and some processed food. The primary goal of this program is to determine if the amounts and types of pesticides found on fruits and vegetables are in accordance with the tolerances set by EPA. Violations of the law occur when pesticides are not used in accordance with label registration and are applied in excessive amounts, or when pesticides are accidentally or deliberately applied to crops on which they are not allowed.
 
There are currently 370 chemicals with tolerances for use in the United States on over 1053 food commodities in twenty food groups. There are numerous other chemicals which have “exemptions from tolerances, pesticides chemicals not requiring a tolerance or and exemption from a tolerance” (40 e-CFR 180, 2007). There is no single method capable of simultaneously analyzing for all of these chemicals in all of the different food commodities.
 
However, our DPX/Micro Luke Method of analysis provides detection of over 120 pesticides over a wide range of food and is sensitive enough to detect pesticide residues a the part per million (ppm) and even some at the part per billion (ppb) level.

Sherry Garris, Lab Supervisor
Chanin Craft, Chemist