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Corn Harvest Quality Report 2012/2013

Contents

  1. Harvest Quality Highlights
  2. Introduction
  3. Quality Test Results
  4. Moisture
  5. Chemical Composition
  6. Physical Factors
  7. Mycotoxins
  8. Crop and Weather Conditions
  9. Planting and Early Growth Conditions - Spring (March-May)
  10. Pollination and Grain Fill Conditions - Summer (June-August)
  11. Harvest Conditions (August-October +)
  12. U.S. Corn Production, Usage, Outlook
  13. U.S. Corn Use and Ending Stocks
  14. Outlook
  15. Survey and Statistical Analysis Methods
  16. Survey Design and Sampling
  17. Statistical Analysis
  18. Testing Analysis Methods
  19. Corn Grading Factors
  20. Moisture
  21. Chemical Composition
  22. Physical Factors
  23. Mycotoxin Testing
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E. Mycotoxin Testing

Detection of mycotoxins in corn is complex. The fungi producing the mycotoxins often do not grow uniformly in a field or across a geographic area. As a result, the detection of any mycotoxin in corn, if present, is highly dependent upon the concentration and distribution of the mycotoxin in a lot of corn, whether a truck load, a storage bin or a rail car.

FGIS’s protocol requires a minimum of a 4540- gram (10-pound) sample from large lots such as barges/sublots and a minimum of a 908-gram (2-pound) sample from trucks to grind for aflatoxin testing. The large sample size for large lots is used so the quantitative testing reflects the average mycotoxin concentration of the entire lot of corn in parts per billion (ppb). The objective of the FGIS sampling process is to minimize underestimating or overestimating the true mycotoxin concentration since accurate results are imperative for corn exports. However, the objective of the Harvest Report 2012/13 assessment of aflatoxins is only to report the frequency of occurrences of the mycotoxin in the current crop, but not specific levels of the mycotoxin in corn exports. It was not feasible to collect 4540 grams per sample for the Harvest Report 2012/13 aflatoxins testing, so a smaller sample size was used. Using a smaller sample size for testing for aflatoxins increases the potential for overestimating or underestimating the specific level of aflatoxins in the lot. However, only the number and percentage of sample test results above several specified thresholds are being reported.

For this study, a 1000-gram laboratory sample was subdivided from the 2-kg survey sample of shelled kernels for the aflatoxin analysis. The 1-kg survey sample was ground in a Romer Model 2A mill so that 60-75% would pass a 20 mesh screen. From this well-mixed ground material, a 50-gram test portion was removed for each mycotoxin tested. EnviroLogix AQ 109 BG and AQ 204 BG test kits were used for the analysis. The DON was extracted with water (5:1), while the aflatoxins were extracted with 50% ethanol (2:1). The extracts were tested using the Envirologix QuickTox lateral flow strips, and the mycotoxins were quantified by the QuickScan system.

A letter of performance has been issued by FGIS for the quantification of aflatoxins and DON using the Envirologix AQ 109 BG and AQ 204 BG kits, respectively.