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Corn Export Cargo Quality Report 2015/2016

Contents

  1. Export Cargo Quality Highlights
  2. Introduction
  3. Quality Test Results
  4. Moisture
  5. Chemical Composition
  6. Physical Factors
  7. Mycotoxins
  8. U.S. Corn Export System
  9. U.S. Corn Export Flow
  10. Impact of the Corn Market Channel on Quality
  11. U.S. Government Inspection and Grading
  12. Survey and Statistical Analysis Methods
  13. Survey Design and Sampling
  14. Statistical Analysis
  15. Testing Analysis Methods
  16. Corn Grading Factors
  17. Moisture
  18. Chemical Composition
  19. Physical Factors
  20. Mycotoxin Testing
  21. U.S. Corn Grades and Conversions
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E. Mycotoxins

Mycotoxins are toxic compounds produced by fungi that occur naturally in grains. When consumed at elevated levels, mycotoxins may cause sickness in humans and animals. While several mycotoxins have been found in corn grain, aflatoxins and deoxynivalenol (DON or vomitoxin) are considered to be two of the important mycotoxins.
The U.S. grain merchandising industry implements strict safeguards for handling and marketing grain with elevated levels of mycotoxins. All stakeholders in the corn value chain – seed companies, corn growers, grain marketers, and grain handlers, as well as U.S. corn export customers – are interested in understanding how mycotoxin infection is influenced by growing conditions and the subsequent storage, drying, handling, and transport of the grain as it moves through the U.S. corn export system.

1. Assessing the Presence of Aflatoxins and DON

To assess the effect of these conditions on aflatoxins and DON development, this report summarizes the results from official USDA Federal Grain Inspection Service (FGIS) aflatoxin tests and from independent DON tests for all the export samples collected as part of this survey. Details on the testing methodology employed in this study for the mycotoxins are in the “Testing Analysis Methods” section.

RESULTS: AFLATOXINS

A total of 408 export samples were tested for aflatoxins for the 2015/2016 Export Cargo Report. Results of the 2015/2016 survey testing are as follows:

  • Of the 408 samples, 369 samples, or 90.4%, had no detectable levels of aflatoxins (defined as less than 5.0 ppb or the FGIS lower reporting level referred to as the “Lower Conformance Level” (LCL)). This 90.4% is greater than the 2014/2015 export samples (85.6%) and less than the 2013/2014 export samples (92.5%).
  • Aflatoxin levels greater than or equal to 5.0 ppb, but less than 10 ppb, were found in 33 samples, or 8.1% of the 408 samples tested in 2015/2016. This percentage is less than the 2014/2015 export samples (12.2%) and greater than the 2013/2014 export samples (6.1%).
  • Only 6 samples, or 1.5% of the 408 samples tested, in 2015/2016 had aflatoxin levels greater than or equal to 10.0 ppb, but below or equal to the FDA action level of 20 ppb. This 1.5% is less than the 2014/2015 export samples (2.2%), but is the same as the 2013/2014 export samples (1.5%).
  • 100% of the samples tested in 2015/2016 were below or equal to the FDA action level of 20 ppb, which is the same as that reported in the 2014/2015 and 2013/2014 Export Cargo Reports.

Comparison of the aflatoxin results in the 2015/2016 export survey with the aflatoxin results in the 2014/2015 and 2013/2014 export surveys suggest fewer incidents of aflatoxins in the 2015/2016 export samples than in the 2014/2015 export samples, but slightly more incidents than in the 2013/2014 export samples. Also, the percentage of all samples below 10 ppb in 2015/2016 was about the same as 2013/2014, but greater than 2014/2015. The percentage of the 2015/2016 export samples (90.4%) below the FGIS LCL of 5.0 ppb is less than the percentage of the 2015 harvest samples (100%) below the FGIS LCL of 5.0 ppb.

RESULTS: DON (DEOXYNIVALENOL OR VOMITOXIN)

A total of 408 export samples were tested for DON for the 2015/2016 Export Cargo Report. Results of the testing are shown below:

  • DON levels of less than 0.3 ppm were found in 361 samples, or 88.5% of the 408 samples tested. This 88.5% is greater than both the 2014/2015 export samples (81.8%) and the 2013/2014 export samples (66.3%).
  • 43 samples, or 10.5% of the 408 samples tested, had DON levels greater than or equal to 0.3 ppm, but less than 0.5 ppm (the FGIS LCL for DON). This 10.5% is less than the 2014/2015 export samples (12.7%) and the 2013/2014 export samples (28.6%).
  • Only four samples, or 1.0% of the 408 samples tested, had DON levels greater than or equal to 0.5 ppm, but less than or equal to the FDA advisory level of 5 ppm. This 1.0% is less than the 2014/2015 export samples (5.6%), as well as the 2013/2014 export samples (5.1%).
  • 100% of the samples tested were below or equal to the FDA advisory level of 5.0 ppm, which is the same as that reported in the 2014/2015 and 2013/2014 Export Reports.

Comparison of the 2015/2016 DON export survey results with the 2014/2015 and 2013/2014 DON export survey results indicate fewer DON incidents in the 2015/2016 export samples than in the samples from the two previous years. All samples were below or equal to 5.0 ppm for all three marketing seasons. The percentage of samples less than 0.5 ppm in the 2015/2016 Export Report (99.0%) was much higher than the DON results reported for the 2015/2016 Harvest Report (87.0%).

2. Background: General

The levels at which the fungi produce mycotoxins are influenced by the fungus type and the environmental conditions under which the corn is produced and stored. Because of these differences, mycotoxin production varies across the U.S. corn-producing areas and across years.

Humans and livestock are sensitive to mycotoxins at varying levels. As a result, the U.S. Food and Drug Administration (FDA) has issued action levels for aflatoxins and advisory levels for DON by intended use.

Action levels specify precise limits of contamination above which the agency is prepared to take regulatory action. Action levels are a signal to the industry that FDA believes it has scientific data to support regulatory and/ or court action if a toxin or contaminant is present at levels exceeding the action level if the agency chooses to do so. If import or domestic feed supplements are analyzed in accordance with valid methods and found to exceed applicable action levels, they are considered adulterated and may be seized and removed from interstate commerce by FDA.

Advisory levels provide guidance to the industry concerning levels of a substance present in food or feed that are believed by the agency to provide an adequate margin of safety to protect human and animal health. While FDA reserves the right to take regulatory enforcement action, enforcement is not the fundamental purpose of an advisory level.

A source of additional information is the National Grain and Feed Association (NGFA) guidance document titled “FDA Mycotoxin Regulatory Guidance” found at http://www.ngfa.org/wp-content/uploads/NGFAComplianceGuideFDARegulatoryGuidanceforMycotoxins8-2011.pdf.

3. Background: Aflatoxins

The most important type of mycotoxin associated with corn grain is aflatoxins. There are several types of aflatoxins produced by different species of the Aspergillus fungus, with the most prominent species being A. flavus. Growth of the fungus and aflatoxin contamination of grain can occur in the field prior to harvest or in storage. However, contamination prior to harvest is considered to cause most of the problems associated with aflatoxin. A. flavus grows well in hot, dry environmental conditions or where drought occurs over an extended period of time. It can be a serious problem in the southern United States, where hot and dry conditions are more common. The fungus usually attacks only a few kernels on the ear and often penetrates kernels through wounds produced by insects. Under drought conditions, it also grows down silks into individual kernels.

There are four types of aflatoxins naturally found in foods – aflatoxins B1, B2, G1 and G2. These four aflatoxins are commonly referred to as “aflatoxins” or “total aflatoxins.” Aflatoxin B1 is the most commonly found aflatoxins in food and feed and is also the most toxic. Additionally, dairy cattle will metabolize aflatoxins to a different form of aflatoxins called aflatoxin M1, which may accumulate in milk.

Aflatoxins express toxicity in humans and animals primarily by attacking the liver. The toxicity can occur from short-term consumption of very high doses of aflatoxin-contaminated grain or long-term ingestion of low levels of aflatoxins, possibly resulting in death in poultry and ducks, the most sensitive of the animal species. Livestock may experience reduced feed efficiency or reproduction, and both humans’ and animals’ immune systems may be suppressed as a result of ingesting aflatoxins.

The FDA has established action levels for aflatoxin M1 in milk intended for human consumption and for total aflatoxins in human food, grain and livestock feed products (see table below).

FDA has established additional policies and legal provisions concerning the blending of corn with levels of aflatoxins exceeding these threshold levels. In general, FDA currently does not permit the blending of corn containing aflatoxins with uncontaminated corn to reduce the aflatoxin content of the resulting mixture to levels acceptable for use as human food or animal feed.

Corn exported from the United States must be tested for aflatoxins according to Federal law. Unless the contract exempts this requirement, testing must be conducted by FGIS. Corn above the FDA action level of 20 ppb cannot be exported unless other strict conditions are met. These requirements result in relatively low levels of aflatoxins in exported grain.

4. Background: DON (Deoxynivalenol) or Vomitoxin

DON is another mycotoxin of concern to some importers of corn grain. It is produced by certain species of Fusarium, the most important of which is F. graminearum (Gibberella zeae) which also causes Gibberella ear rot (or red ear rot). Gibberellazeae can develop when cool or moderate and wet weather occurs at flowering. The fungus grows down the silks into the ear, and in addition to producing DON, it produces conspicuous red discoloration of kernels on the ear. The fungus can also continue to grow and rot ears when corn is left standing in the field. Mycotoxin contamination of corn caused by Gibberellazeae is often associated with excessive postponement of harvest and/ or storage of high-moisture corn.

DON is mostly a concern with monogastric animals where it may cause irritation of the mouth and throat. As a result, the animals may eventually refuse to eat the DON-contaminated corn and may have low weight gain, diarrhea, lethargy and intestinal hemorrhaging. It may cause suppression of the immune system resulting in susceptibility to a number of infectious diseases.

The FDA has issued advisory levels for DON. For products containing corn, the advisory levels are:

  • 5 ppm in grains and grain co-products for swine, not to exceed 20% of their diet,
  • 10 ppm in grains and grain co-products for chickens and cattle, not to exceed 50% of their diet, and
  • 5 ppm in grains and grain co-products for all other animals, not to exceed 40% of their diet.

FGIS is not required to test for DON on corn bound for export markets, but it will perform either a qualitative or quantitative test for DON at the buyer’s request.