Seaweed Identity - it's more than a name - Maine Coast Sea Vegetables

Sea Vegetables from a Trusted Source

Longtime customers of Maine Coast Sea Vegetables know our company was founded and based upon personal relationships with the harvesters and seaweed companies who supply us.  Those relationships were established over many years of working together, inspecting harvest grounds and processing plants, navigating Organic Certification standards, learning from each other, and, on many occasions, eating sea vegetables together.  These elements are all part of our Supplier Verification program that helps ensure quality, safety, and accuracy.

Supplier verification and a long tradition of personal relationship means customers can trust that our products are what we say they are.  When we sell a bag of dulse leaf or dulse flakes, they can be reassured that it’s Palmaria palmata and not some other red seaweed. Although there is also a West Coast red seaweed called “dulse”, it is actually Palmaria mollis, which we do not sell. Where someone unfamiliar with seaweed could confuse rockweed with bladderwrack, our customers know our rockweed is Ascophyllum nodosum and our bladderwrack is a Fucus species

This is especially important with milled seaweed forms such as flakes, granules, and powder, because distinguishing traits like frond shape, size, and texture are lost. All that’s left is color, taste, and smell.  Here, in addition to our trusted supplier relationships, we rely upon our expertise, documentation, and knowledge of milling operations to ensure product integrity. 

How can I be sure I get what I paid for?

When you buy sea vegetables from MCSV, you can be sure you're getting what you paid for. Sadly, however, we can’t speak for every seaweed company in the world.  As in other fisheries, sometime bad actors may substitute one thing for another.  A notorious example from the fish world is red snapper.  More than one investigation has revealed that much of the red snapper bought by consumers is actually a cheaper fish such as tilapia. 

That being said, how is a consumer to know that Irish moss powder purchased on-line from some company other than MCSV truly is wild-harvested North Atlantic Chondrus crispus, and not farmed Gracilaria from the sub-tropical Pacific?  After all, once either one is milled into powder, they can both look much alike.  For more about how they differ, read our blog post on Sea Moss.

Irish moss powder

This is even more true when powdered seaweed is encapsulated into a supplement.  Seaweed is a popular supplement ingredient because it’s not only a good source of iodine but also contains various minerals and bioactive compounds. Since different sea vegetable species contain different amounts of iodine and other substances, when manufacturers formulate and market supplements, they usually have a very specific seaweed species in mind. 

The FDA began regulating dietary supplements in 1994.  Among other things, the FDA requires supplement manufacturers to establish identity and other specifications for botanical ingredients. Furthermore, companies are required to conduct at least one appropriate test or examination to verify the identity of any dietary ingredient component.  Under 21 CFR 111, manufacturers are responsible for this testing, not suppliers.

Among the most frequent complaints lodged by the FDA against supplement manufacturers are failure to establish identity specifications and/or failure to document testing.  Nutritional supplement manufacturers are now accustomed to having to verify the identity of powdered botanicals such as echinacea, goldenseal, ginseng, and others.  These requirements, of course, also apply when they use seaweed.

Testing for Botanical Identity

This brings us to the purpose of this article, which is what is the best test for confirming the botanical identity of dried seaweed, whether it be in whole leaf or milled form?

Our long history of having seaweed tested for things like contaminants or vitamins and various nutrients has taught us that methods developed for other foods aren’t always well suited for seaweed.  We’ve also found that even when the test method is appropriate, different labs sometimes end up with different results. 

Some of the uncertainty can be attributed to the simple fact that seaweed just hasn’t been tested as extensively or for as long as other food ingredients.  Some is also due to seaweed’s unique and complex composition. This is no less the case when it comes to verifying the botanical identity of seaweed.

The FDA doesn’t specify what test a manufacturer must use to verify botanical identity.  The test just has to be based on science or a proven method.  Companies can even use organoleptic properties like appearance, texture, odor, taste, and mouthfeel.  This works well when whole plants, such as fresh or dried whole leaf dulse, are evaluated by people with expertise.

However, once a plant has been dried and ground into powder, more sophisticated methods are required. Some of the tests used for non-seaweed botanicals include High Performance Thin Layer Chromatography (HP-TLC), High Performance Liquid Chromatography (HPLC), Mass Spectrometry (MS), Gas Chromatography (GC), Advanced Flash Column Chromatography (AFCC), and others.

There’s no mistaking this product for anything other than premium grade 100% whole leaf dulse!


Can you tell what species this is? (Hint: it’s not dulse!)

What these methods share in common (besides technical jargon) is that they separate, identify, and quantify the compounds present in a botanical, to be compared to those found in a known reference material.  Test results may be shown as banding patterns, sometimes in black and white and sometimes in color, or as line graphs with peaks and lows for various compounds.  These can be thought of as the plants’ fingerprint or signature. 

Reference materials for hundreds of botanicals can be purchased by testing labs or developed in-house.  To be reliable, though, a reference material must be validated by experts and by more than one lab and validation method, and they should always start with whole plants.  From there, the reference plant has to be processed in the same fashion as the test material to yield a valid comparison.  This is because processing can affect the levels of compounds or even change their structure, especially if heat or pressure are involved.  Other considerations for a valid comparison might involve where, how, and when the plant was grown and harvested.

A Cautionary Tale

For many botanicals, if not the majority, methods such as HP-TLC and the others mentioned earlier have been extensively validated and are widely accepted.  For seaweed, however, we have reason to believe these methods need further development before they can be considered reliable. We have recently seen more manufacturer customers request or conduct botanical identity testing on seaweed, no doubt due to increased FDA scrutiny.  They often turn to the tried-and-true test methods used for other botanicals. On some occasions, however, those test results can lead to conclusions that we know are just wrong.

One example occurred after a manufacturer customer bought some of our dulse powder. Per FDA regulations, they sent some of the powder to a lab to verify botanical identity, using HP-TLC.  Understandably, they were quite upset when the lab reported that the dulse powder was not, in fact, dulse, and they requested a refund.  We were equally upset, as well as surprised.  After scrutinizing our records, examining the powder, and questioning the source, we concluded that the dulse powder was without a doubt dulse powder.  There was no mistake on our end and no chance of fraud, which meant the lab had to have gotten it wrong.

The lab stood by its results, but our dialogue raised some questions with their method validation and, importantly, with the reference material dulse they had used for comparison.  For one thing, they compared dulse powder with dulse leaf. Had it been processed in the same fashion as our dulse powder?  Did the reference plants come from the same region as our dulse?  What season had it been harvested in? Was it material that had been harvested and dried some time before, or was it from a more recent harvest?

The lab had no clear answers to any of these questions. We decided the only way to resolve the matter was to have the dulse powder tested ourselves by a different lab.  The question then became, since we weren’t confident in HP-TLC, what method should we use?

Genetic Identity

After some research and after consulting with one of our trusted partners (recall those personal relationships described earlier), we found a lab with expertise using genetic analysis to identify seaweed.  By now, most people are familiar with genetic profiling and identification.  It’s been made famous in true crime stories for  identifying the culprit and exonerating the innocent.  Ancestry is another well-known application; people can build a family tree or find long-lost cousins simply by sending their spit in a tube to a company for genetic analysis. 

Genetic analysis is a powerful scientific tool that’s been used to untangle the relationships, evolution, and heritage of seaweed species.  Over the past decades, scientists have amassed a vast library of genetic sequences unique to many hundreds of species, especially for commercially important ones like dulse and Irish moss.  They have also become adept at amplifying and sequencing DNA from just small amounts of organic matter.  This is how, for example, a forensics lab can identify who licked the seal on an envelope from the traces of DNA in their saliva.

If DNA analysis is good enough for a court of law, then we believe it is certainly good enough for determining the true species of a powdered seaweed.  After sending a sample of our dulse powder to the lab for analysis, we were exonerated a week later when they reported that DNA extracted from the powder was a 100% match with Palmaria palmata DNA.

We needed no further convincing that HP-TLC and similar methods need more development and validation before they can be trusted with seaweed. Until that happens, genetic testing is our method of choice.  We now make it clear to manufacturing and ingredients customers that we accept product returns based on wrong identity only when it’s confirmed through genetic testing, and not through any other method.  We also make it clear that, per FDA regulations, testing responsibility falls on the company using the seaweed in a supplement, and not on MCSV.

As with any testing method, however, genetic analysis has its limitations.  First and foremost, the substance being tested has to have viable DNA present, and some forms of processing destroy DNA.  When we sent the same lab a sample of suspect Irish moss powder purchased by one of our customers from a company located in China, they told us they couldn’t extract any usable DNA. This was probably because of how it had been processed.  High temperatures, high pressure, and bleaching agents can all destroy DNA.  Of course, our minimally processed sea vegetable powder, flakes, or granules are never subjected to any of these processing methods and are therefore raw foods with intact DNA, but we can’t say the same for other company’s products.

This limitation is just as true for HP-TLC and other similar methods.  The same things that damage or destroy DNA can do the same to compounds normally present in botanicals. A highly processed product will not have the same compound fingerprint as a minimally processed product, even if they’re both the same species.  Perhaps the testing lab had compared our dulse powder to dulse processed in such a way that its compounds had been altered.

Whatever the cause of the testing failure, it’s clear that just because an analytical method is widely accepted for botanicals of terrestrial origin doesn’t mean it works just as well with botanicals of marine origin.  Or at least not without extensive testing and validation by multiple labs, not just one or two.

We have been working with a company to further refine HP-TLC methods for seaweed.  This company makes and supplies HP-TLC testing equipment, so they have an incentive to make sure it’s done correctly.  We’re doing this not because we have any doubts about the provenance of our sea vegetables, but because we know some customers are required by law to verify.  We want to make sure everyone gets it right!

Seaweed identity