Genetically engineered (GE) foods continues to be a topic of public interest. Other names for genetically engineered foods that you may hear include “genetically modified foods” or GMO, “Biotech”, and “bioengineered” foods. The FDA uses the term genetically “engineered” to differentiate it from other methods that can also result in genetic modification such as cross-breeding and natural genetic mutations. GE foods are generally prepared by removing a section of DNA from one organism and placing it in a different host. The new DNA construct is referred to as recombinant DNA (rDNA). The host will not reject it as a foreign object but will simply accept it as information. This is similar to cutting and pasting words in a document. The reader will not recognize the pasted section as being any different from the rest of the information in the document.

Apart from creating rDNA, other methods of making GE foods could include deactivating specific genes, or inducing genetic mutations. The most common genetically modified foods in the US are corn, soybean, canola and sugar beets. Because these ingredients are so common in food products, a very large proportion of our processed food supply (50-60%) contains GE ingredients. GE soybean is made by combining glyphosate-resistant gene present in the soil bacterium Agrobacterium tumefaciens, into soybean DNA. Glyphosate is the active ingredient in broad-spectrum weedicides such as round up. Glyphosate binds with an enzyme called 5-enolpyruvyl-shikimate synthase (EPSPS) in plants and bacterial cells. EPSPS  catalyzes the production of certain amino acids. Without this enzyme, plants will starve to death. The version of EPSPS in Agrobacterium has a different shape allowing it to make the needed amino acid even when sprayed with roundup. Therefore when Agrobacterium DNA is incorporated into soybean, the plant “learns” how to make EPSPS which acts as a backup source to produce the amino acid it needs to survive in the presence of Roundup. That’s why GE soybean are called “roundup ready”. 

GE corn, also called Bt corn, was developed by combining a gene from the bacterium Bacillus thuringiensis, and placing it in corn DNA. The gene produces a protein that is resistant to the European Corn Borer pest. This pest has damaging effects on corn by burrowing the ears and stalks, causing the plant to fall over.

The most common application of GE plants in the US includes resistance against herbicides, pests, and viruses. However several other benefits are possible including improvement in crop yields, improved nutritional profile and food functionality. In animal foods benefits may include:

  1. Increased milk and meat production
  2. Production of leaner meats
  3. Production of better quality fats
  4. Harvesting of production of proteins, enzymes, and pharmaceuticals essential to human disease treatment
  5. Development of tissues and organs for transplant into humans

 

Many concerns have been put forward regarding the use of GE foods. Some of the concerns include:

  1. Creation of “superweeds” i.e. noxious herbicide-resistant weeds, produced from cross-contamination with GE ‘relatives’
  2. Creation of “superbugs” i.e. pests that become highly resistant to pesticides
  3. Reduction of biodiversity as a result of resistant pests and weeds becoming more competitive
  4. Creation of new allergens
  5. Creation of foods with high levels of toxicity and anti-nutrients
  6. The unknown repercussions of “tampering with nature”

 

Despite these concerns, the FDA has determined that GE foods currently approved for distribution are “substantially equivalent” with their conventional counterparts. Therefore, unless the GE food is not substantially equivalent to the conventional form, GE labeling remains voluntary.

In regulating GE foods, the FDA takes a collaborative approach by partnering with the USDA-APHIS and the EPA. FDA evaluates the safety of the GE food for human and animal food consumption. This includes evaluation of the material for the presence of food additives. You should note that food additives are substances that are added by the action of man. Therefore, new potentially hazardous substances created as a result of GE fits this definition. The EPA evaluates the GE food to determine the level of pesticidal substances present. The USDA-APHIS conducts the assessment to determine the potential effect of the GE organisms on the health of the GE plant e.g. new susceptibility to diseases and the effect on other plants and non-target organisms.

The burden of proof on the safety of the GE food material is on the developer. The FDA has a voluntary program to review and approve GE foods. This involves providing the FDA with relevant documentation based on rigorous scientific data and research to prove safety and substantial equivalency. The FDA encourages developers of GE organisms to consult with the agency prior to this application. In this way, they can be advised by the agency on what concerns it has and therefore what supporting evidence would be required.

AquAdvantage Salmon

So far, the only GE animal food that has been approved, is AquAdvantage Salmon. The salmon was genetically engineered by removing genes from the Chinook salmon and the Ocean pout and combining them with the DNA of Atlantic salmon. Chinook salmon is the largest salmon. It contains a growth hormone gene that can be turned on by a gene in the Ocean pout. Hence Atlantic salmon is able to grow almost twice as fast as the conventional Atlantic salmon. All other characteristics of the salmon including nutritional quality are the same except for growth rate.

Regulatory Approach in European Union 

While the US takes a more relaxed position on the labeling of GMOs, the European Union (EU) requires labeling. The difference between the EU and the US is that the US takes the position that the safety of the product is based on its final characteristics rather than the process in which it was made. On the other hand, the EU considers both the process and end-product to be important in evaluating safety. Which position do you think is the better approach? 

Courtney Simons
Administrator
Courtney Simons is a food science professor. He holds a BS degree in food science and a PhD in cereal science from North Dakota State University.
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