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Corn Export Cargo Quality Report 2014/2015

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 any elevated levels of mycotoxins. All stakeholders in the corn value chain – seed companies, corn growers, grain marketers and 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.

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

FGIS tested 411 export samples for aflatoxins for the Export Cargo Report 2014/2015. Results of the 2014/2015 survey are as follows:

  • 352 samples or 85.6% of the 411 samples tested in 2014/2015 had no detectable levels of aflatoxins (defined as less than 5.0 parts per billion (ppb) or the FGIS lower reporting level). This 85.6% is greater than the 77.8% of the 2012/2013 export samples and less than the 92.5% of the 2013/2014 export samples.
  • 84 samples or 12.2% of the 411 samples tested in 2014/2015 had aflatoxin levels greater than or equal to 5.0 ppb, but less than 10 ppb. This 12.2% is greater than the 10.1% of the 2012/2013 export samples and the 6.1% of the 2013/2014 export samples.
  • 9 samples or 2.2% of the 411 samples tested in 2014/2015 had aflatoxin levels greater than or equal to 10.0 ppb, but less than or equal to the FDA action level of 20 ppb. This 2.2% is less than the 12.1% of the 2012/2013 export samples but about the same as the 1.5% of the 2013/2014 export samples.
  • 100% of the samples tested in 2014/2015 were below or equal to the FDA action level of 20 ppb, which is the same as reported in the 2012/2013 and 2013/2014 export reports.

Comparing the 2014/2015 aflatoxin export survey results to the 2012/2013 and 2013/2014 export survey results suggests that there were fewer incidents of aflatoxins in 2014/2015 export samples than in 2012/2013 export samples, but slightly more than in 2013/2014 export samples. Also, the percentage of all samples below 10 ppb in 2014/2015 is about the same as 2013/2014 and greater than 2012/2013. The percentage of all samples below 10 ppb in 2014/2015 was similar to the aflatoxin results from the Harvest Report 2014/2015.

RESULTS: DON (DEOXYNIVALENOL OR VOMITOXIN)

A total of 411 export samples were tested for DON for the Export Cargo Report 2014/2015. Results of the testing are shown below:

  • 336 samples or 81.8% of the 411 samples tested had DON levels less than 0.3 parts per million (ppm). This 81.8% is less than the 94.0% of the 2012/2013 export samples and higher than the 66.3% of the 2013/2014 export samples.
  • 52 samples or 12.7% of the 411 samples tested had DON levels greater than or equal to 0.3 ppm, but less than 0.5 ppm. This 12.7% is greater than the 3.5% of the 2012/2013 export samples and less than the 28.6% of the 2013/2014 export samples.
  • 23 samples or 5.6% of the 411 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 5.6% is greater than the 2.5% of the 2012/2013 export samples and the 5.1% of the 2013/2014 export samples.
  • 100% of the samples tested were below or equal to the FDA advisory level of 5 ppm, which is the same as that reported in the 2012/2013 and 2013/2014 export reports.

Comparing the 2014/2015 DON export survey results to the 2012/2013 and 2013/2014 DON export survey results indicates that there were fewer incidents of DON in the 2014/2015 export samples than in 2013/2014 export samples and more incidents of DON than in 2012/2013 export samples. All samples were below 5 ppm for all three marketing seasons. The percentage of samples less than 0.5 ppm in 2014/2015 (94.5%) was much higher than DON results reported for the Harvest Report 2014/2015 (80.2%).

1. 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.

2. 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 type of 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.

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.

3. 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). Gibberella zeae 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 Gibberella zeae 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 will perform either a qualitative or quantitative test for DON at the buyer’s request.