Case Study: High-Sensitivity Testing for Enogen Corn
What is Enogen corn?
Launched in 2011 by Syngenta®, Enogen® corn is a genetically modified (GMO) variety of corn developed to drive efficiencies in ethanol and cattle feed production—two industries that account for 90% of US domestic corn use. Enogen corn contains a special trait that enables it to produce within the kernel a high amount of alpha-amylase, an enzyme that breaks down starch to sugar. This enzyme saves on the cost and energy of converting corn starch to alcohol in ethanol production, and is claimed to improve digestibility of cattle feed. Enogen corn adoption has grown rapidly across US. For example, in North Dakota, refiners have been looking to secure up to 16 million bushels of the Enogen corn—about 4% of the state’s total annual production.  Adoption in the cattle feed segment has also accelerated dramatically since introduction. Syngenta reported double-digit growth in their 2021 financial report.
The map below from IP Field Finder (ip360.agconnections.com) illustrates that Enogen farms are present in virtually every corn growing region in the US in high numbers. (click image to expand)
Impact on Corn Food Product Quality
You may have experienced this for yourself—if you chew on a piece of tortilla or bread for a bit longer, it will start tasting sweeter. This is because the alpha-amylase in your saliva starts converting the starch content to sugar as part of the digestion process in your mouth. The alpha-amylase produced in Enogen corn has a similar impact of catalyzing starch hydrolysis—potentially to a point of dysfunction—resulting in issues like soupy grits, crumbly cornbread, and sticky tortillas.
The enzyme is also designed to be heat-resistant and works optimally at temperatures at which the corn is cooked. Enzymes can remain active well after the cooking process is over and continue to impact the starch quality of packaged foods, making tortilla dough sticky or the product fragile. The nixtamalization process (a key step in corn processing in which the corn is soaked and cooked in an alkaline solution) is especially sensitive to alpha-amylase, and caused one of our largest customers to experience significant masa flour quality incidents. They also reported that cornbread made with corn flour containing the Enogen corn crumbled on its own when stored in a hot box or on a hot shelf for more than an hour.
“The starch content is obviously different in this corn. Tamales don’t bind. When you make the product, it falls apart.” – Juan Galván, VP Amapola
In order to keep Enogen corn out of the food supply chain, Syngenta has implemented a stewardship program that includes regulating aspects of seed and produce distribution and spacing between farms. For the most part, this program is successful, but Enogen corn does at times come into cross-contact with food-grade corn during shared transportation, handling, and storage infrastructure, as well as through cross-pollination events from wind and weather. This commingling risk is supported both by the growing number of EnviroLogix customers seeking Enogen testing, as well as positive customer samples we have received for PCR tests conducted in our TotalTest Labs.
“We cut about 400 to 500 feet off the end of 400 acres that we had to bin separately—and it was contaminated. We tested it and it wasn’t going to meet specs.” -Mark Jost of Henderson, Nebraska 
A lot of cross-contact risk conversation revolves around the level on concentration of the enzyme. The science suggests that if an enzyme is present in a supportive environment, it will start degrading the starch by acting as a catalyst. This implies that the enzyme may not get consumed in the reaction, but will simply move to the next site. This would mean that practically any dose of the enzyme that goes undetected can lead to a uncontrolled reaction and have severe consequences on the production process. Novozyne, a leader in enzyme preparation for the baking industry, warns that even a slight amount of overdosing of enzymes in food preparation can lead to unacceptable products. The North America Millers Association (NAMA) has documented that even one kernel mixed with ten thousand (0.01%) can disrupt food processing operations. While each product has different level of associated risk, any process involving heating and/or acidic/alkaline exposure of corn for a long duration is a high-risk process in the presence of the alpha-amylase enzyme.
Assessing a Customer Need
An EnviroLogix customer, one of the largest corn millers in the United States, was experiencing multiple batch failures of masa flour, an issue that had to be escalated to their Head of Quality. Only after performing DNA tests was the root cause determined to be cross-contamination with Enogen corn. Yet the issue had arisen despite the customer testing all inbound corn for Enogen using following methods:
- Lateral flow device (LFD) test at the decision point- LFD tests provide real-time guidance to staff on whether to accept or reject a load. But, the EnviroLogix test they were using at the time was only specified to detect contamination at a level of 1 in 400 kernels (0.25%).
- Lab-based PCR test-Performed by trained scientists in a lab setting, Lab-based PCR tests reduce the possibility of error but take a few days to return results, making them an impractical choice for inbound screening. If Enogen corn is accepted into inventory before the test result is obtained, it is already too late.
A Breakthrough Solution
With the PCR results arriving too late, and product quality issues occurring despite inbound grain tested using a test specified to detect 1 Enogen corn grain in 400 (0.25%), there was a clear need to revise the acceptance criteria for inbound corn cross-contact to a much lower level. To enable this revision, the limit of detection for the test used to monitor each truck would also need to be lowered to help mitigate this ongoing and increasing risk they were seeing. After additional internal consideration, they told us- “Increase sensitivity of the strip to at least 1/1000 although 1/2000 is the ideal level since 0.0625% is threshold where we start seeing issues”. With the evolving needs of the grain industry always at the forefront of our research and development, EnviroLogix was ready with TotalTarget™ for Amylase Corn—a breakthrough LFD solution able to detect Enogen in corn at 1 in 2,500 kernels (0.04%).
- Increased Sensitivity – TotalTarget for Enogen is 6 times more sensitive than the existing low sensitivity test to enable detection of Enogen above 0.04% contamination.
- Common Workflows – Workflows for TotalTarget Enogen and TotalTox™ Mycotoxin test kits mesh seamlessly. With the same sample prep and simultaneous reading, operators can test for Enogen and mycotoxin contamination side-by-side in under 10 minutes.
- Updated Extraction – Safer and easier extraction process that no longer requires Hydrochloric Acid (HCl)
- Reader Enabled – No need to rely on visual test line results. Get an instant objective read with the QuickScan Reader.
- Audit-Ready Data – Whether you download your data directly from the QuickScan or access it online through our new TotalHub data management system, record keeping and reporting are just a few clicks away.
By adopting this new high sensitivity test, the customer was able to more than meet their threshold needs with an on-site test that is fast and simple. With TotalTarget for Enogen, they were able to:
- Dramatically reduce the risk of Enogen contamination of purchased food-grade corn, potentially averting hundreds of thousands of dollars in operational disruptions, product recalls, and inventory disposal.
- Save significant time and effort with training and testing by implementing the common workflow for Enogen and Mycotoxin testing that utilizes the sampling protocols and testing steps that operators already know.
- Further insure against contamination risk by mandating that all upstream corn suppliers test for Enogen using the new TotalTarget high sensitivity test before delivering corn to them
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-  https://www.ers.usda.gov/topics/crops/corn-and-other-feedgrains/feedgrains-sector-at-a-glance/
-  https://www.syngenta-us.com/corn/enogen-feed
-  https://www.agweek.com/business/enogen-corn-comes-north
-  https://www.nytimes.com/2011/02/12/business/12corn.html
-  https://brownfieldagnews.com/rural-issues/enogen-vs-food-grade-coexistence-issue-nebraska/
-  https://www.tortilla-info.com/downloads/1-PART-Forman%20-%20Enzyme%20Functionality.pdf
-  https://www.ecowatch.com/gmo-corn-syngenta-enogen-2324704813.html