DNA Testing Reveals What’s Really for Dinner


DNA Testing Reveals What’s Really for Dinner

By Mike Howie

When you walk into a steakhouse and order a cut of Kobe beef, you expect Kobe beef, not a cheaper, less flavorful variety. And when you order white tuna at your favorite sushi bar, you expect white tuna, not some fish called escolar that’s so toxic and wreaks such havoc on the human gastrointestinal tract that it’s been banned in Japan for 40 years.

But substitutions like these happen. All the time. Everywhere. Welcome to the world of food fraud.

The Ingredients

You might think this problem only exists in the world of high-priced fine dining, with restaurants and markets looking to make easy money by selling cheap (or lesser known) foods as their pricier (or more widely known) counterparts. But there’s a wide variety of products, including everything from the milk and coffee you drink with your breakfast to the olive oil and black pepper you use while cooking dinner, that are somehow adulterated or even completely fabricated. Moreover, it largely goes unnoticed — many consumers would be hard pressed to tell the difference between steelhead trout and genuine salmon, for instance, or notice that some of the meat in Red Lobster’s lobster bisque is actually langostino.

Of course these adulterants vary depending on what the final product is supposed to be. Some are just a little strange — there could be sheep’s milk mixed into your cow’s milk — while some are less healthy than what they substitute, like high-fructose corn syrup in your honey. But some can cause serious problems: peanut and hazelnut oils cut into olive oil, possibly even the extravirgin variety, could cause serious allergic reactions in people with nut allergies.

Applying Heat

Beyond being a frustrating and possibly dangerous annoyance, this gastronomical bait and switch is expensive, costing a staggering $49 billion annually. But now governments and consumers alike are becoming increasingly aware of the situation, and they’re looking for ways to put an end to it.

While individual consumers can’t do much more than look for third-party verification of what any given label claims, governments can attack the problem from multiple angles. In the U.S., the Obama administration launched a system in early 2015 that tracks the origin of every wild fish and crustacean shipped into the country. Meanwhile, the FDA has the power to inspect all imported food — though it only has the resources to physically examine a fraction of it — and refuse entry to anything that appears to be misbranded or adulterated. They have also created a list of recognized seafood names that companies can use, and, more scientifically, developed a method of generating DNA barcodes that can be used to identify fish to ensure regulatory compliance.

Taste Test

DNA barcodes are similar to the barcodes you see on everyday products, but instead of telling you the name of a product and its price they help you identify what animal a sample came from. Each barcode is a single gene sequence that can be compared to DNA extracted from a sample to identify what the animal truly is. Unlike chemical testing, which only allows you to test whether or not an ingredient is present in a sample and in what quantity, DNA testing can reveal both expected and unexpected ingredients. It allows you to take a completely unknown sample and find outexactly what it is.

Next-generation sequencing (NGS) is similar to the barcode method, in that it also uses a single gene sequence, but different in that it can replicate it thousands of times from a single sample. And while barcoding uses a single set of universal primers, NGS uses validated universal primers as well as species-specific primers.

One company that is pioneering the use of NGS is NSF International, an independent, accredited organization that tests and certifies products in the interest of public health. NFS developed its method to identify the source of small fragments and old, degraded pieces of DNA, like those commonly found in processed and cooked foods. For this to work, its scientists had to create their own primers, which they did by using a proprietary database containing thousands of validated DNA reference sequences from museum specimens. They then sequenced this source DNA to find regions of the genome that uniquely identified each species and used that information to create their primer sets. The end result of all this work is that NSF International can now use its targeted NGS method to identify over 10,000 species of botanicals, animals, fungi and bacteria in both raw ingredients and finished products. The method is specific enough to distinguish between closely related species, including hybrid plants that may contain thousands of species in a single genus, and can identify every ingredient in processed and ground products, including any fillers, contaminants and undeclared additives.

Served with Pride — and Honesty Obtaining this level of detailed information from routine DNA testing will help prevent adulterated and fabricated food from ever reaching the market, putting an end to food fraud before it can even begin. The supermarkets and restaurants of the world will be able to look at the results of a test and see that they’re getting what they paid for. It will help them to build an honest reputation — something that, in the long run, should be far more beneficial than the quick buck they could make defrauding their customers.

Such exacting third-party verification will also finally allow those customers to be certain that what they buy — and, more importantly, what they eat — is “the real deal.”