Identifying Areas Within Peanut Fields Which Are at High Risk for Aflatoxin Contamination

Summary

Aflatoxin is a natural carcinogen that occurs in peanuts under drought stress. We developed a technique to identify areas in a peanut field at high-risk for aflatoxin contamination so that peanuts in these areas can be separated from the remainder of the crop.

Situation

Aflatoxin is a potent carcinogen and toxin which occasionally finds its way into our food supply. Aflatoxin contamination of peanut occurs when the common fungi infect peanut kernels under drought stress prior to harvest. It is well known that aflatoxin contamination is not uniformly distributed within peanut fields. It is also well known that areas within a field which are prone to drought stress are at higher risk for aflatoxin contamination. Despite this knowledge, there is no suitable method for identifying and delineating high risk areas. Identifying high-risk areas would allow producers to harvest these areas separately and eliminate the potential of mixing aflatoxin-contaminated peanuts with the remainder of the crop.

Response

We initiated a project to evaluate remote sensing as a technique for easily identifying drought-stressed areas in a peanut field. To do this we used tractor-mounted and airborne multispectral cameras in a 30-acre rain-fed peanut field to create multispectral images of the crop at critical times during the growing season. Multispectral images capture the crop's reflectance at specific wavelengths. Measured reflectance was analyzed mathematically to identify areas of drought stress. To verify these findings, we also instrumented the field with soil and temperature sensors. During harvest, we collected peanut samples at regular intervals throughout the field and analyzed them for aflatoxin concentrations.

Impact

The multispectral images were successfully used to identify areas of drought stress in the field. Drought stress was verified by the moisture and temperature sensors. Because the 2006 growing season was very dry, aflatoxin concentrations in peanut kernels were high in drought-stressed areas of the field. Our techniques shows great promise as a tool for producers to identify and segregate areas of the field at high risk for aflatoxin contamination. Segregation of high-risk areas can save the producer money as well as improve the safety of our food supply. The technique will be evaluated over several fields during 2007.

State Issue

Food Safety

Details

• Year: 2006
• Geographic Scope: Multi-State/Regional
• County: Tift
• Program Areas:
  • Agriculture & Natural Resources