Analytical Chemistry Demystifying Genetically Modified Food

Genomics has created significant changes in how we view ourselves, as well as how we create and manufacture products that affect our health, well-being, and even our environment. One change that’s been controversial since it was introduced more than 20 years ago is the genetic modification of food and crops.

Genetically modified organisms (GMO) has not yet been shown to be harmful to human health, and has the backing of many medical and scientific societies, including the World Health Organization, U.S. National Academy of Science, American Medical Association, and the European Commission.

However, consumers are increasingly seeking to avoid the presence of GMO in food, opting to purchase foods labeled under the USDA’s National Organic Program (since organic food, under U.S. law, cannot contain transgenic or otherwise altered organisms), or private certifiers like the Non-GMO project. The American market for organic foods is estimated at about $40 billion, and continues to expand.

To meet this consumer demand (and follow federal and European regulations), the organic food industry is required to ensure that organic foods contain no — or nearly no — GMO components. In Europe, this threshold is strict, at no more than 0.9 percent GM. In the U.S, looser standards prevail, but some federal legislation and state laws are aiming to adopt the 0.9 percent threshold.

Meanwhile, some retail sellers of GM-free and/or organic foods have attempted thresholds approaching zero. Such efforts have led to a new role for analytical chemistry: the analysis of foods for GMOs, or the metabolites and protein products produced by these inserted genes.

New Definitions of GM

In short, a genetically modified organism has traditionally been one that has had a gene inserted in it from a different species. However, more recent approvals have included products that have an inserted gene from another part of the same genome. Still other variants of GM include genes that include regulatory changes, without actually expressing proteins themselves, and the results of gene editing (like CRISPR-Cas9), which aim at precision splicing of DNA to cause some effect in a mature plant (or animal).

New applications of chemistry

These technological changes and changing consumer demands have resulted in several different testing methods, and the need for analytical chemists involved in food testing to adopt new techniques. These methods include:

• Mass spectrometry. This familiar technique can determine the exact amount and structure of a protein expressed by a transgenic (inserted) gene. However, this method has been hampered by the fact that food processing can damage and denature proteins, and can’t be used to detect certain genetic modifications that did not result in an expressed protein.
• The Polymerase Chain Reaction. This technique has been the most dominant in genetic and expression (i.e., protein) analysis for more than two decades. Real-time PCR (also known as qPCR), which determines the presence and amount of a gene, has been the standard technique for identifying specific genes and comparing them to a reference genome.
• Microarrays. A number of new DNA microarrays, miniaturized “labs on a chip” that incorporate hundreds or even thousands of labeled DNA expression products, have been developed for identifying the DNA inserted into another species. The first test designed for monitoring genetically modified organisms, a combined microchip-PCR and microarray system called MACRO, was developed in 2014. This high-throughput system can read out a total of 91 targets, covering 97 percent of all genetic modifications (as of 2012)

• DNA sequencing. This newer technique, which can take samples and ultimately determine the sequence of a whole genome or part of a genome, is taking over from PCR and microarrays in most molecular biology laboratories. Its strength for analytics and detection of GM inserts is its ability to find novel genes, which could help determine unanticipated placement of transcript genes, or the extension of “contamination,” in which GM DNA from a field manages to make its way to an organic crop field.
• Allergen research. One concern of consumers and some watchdog groups about GMOs is the potential to introduce new allergens into the food supply. While a number of known allergens (Brazil-nut albumin, for example) had accidentally been incorporated in foods during early experiments, no known new allergen has been seen to be introduced by GM foods. Of the eight most common allergens (peanuts, milk, wheat, eggs, fish, tree nuts, soy, and shellfish), wheat and soy have GM versions that are integrated into food crops. However, chemists are using a number of techniques typically applied to allergen detection, including LC-MS, which have been used to determine allergenic proteins in recent years.
• Metabolomics. Here, several approaches can detect the fingerprints of GM foods, satisfying demand for monitoring composition, studying possible unintended modification and fulfilling labeling issues. In addition, metabolomics using GC-MS, LC-MS, CE-MS, and NMR could help identify issues with raw material quality, safety, food storage, shelf life and the effects of post-harvest processing.

While the safety of GM foods is a matter of some controversy, the popularity of organic and non-GM food is increasing rapidly. This phenomenon is creating new commercial opportunities for farmers, food processors, and consumer food companies — and analytical chemistry is playing a more important role in determining the presence or absence of GM products.

Feel free to reach out for a conversation about how to equip your lab to meet the analytical demands of this quickly growing field.