When some biology students examined various sushi restaurants, they detected fraud

Fish is one of those love or hate kind of foods. The smell is especially pungent when it is raw, and the taste of the ocean even when it is cooked does not always appeal to everyone. That being said, sushi is a favorite of many people and it is considered quite healthy which makes it even more appealing. However, the key ingredient in most sushi, fish, can be of questionable quality. Do you actually know that you are eating salmon sashimi or could it be disguised as another fish?
A Canadian biology teacher named Dr. Jennifer McDonald from Fanshawe College decided she wanted her class to think critically about what is put in front of them. To add a fun edge, she decided that her students would take part in an experiment testing fish DNA with the fish from sushi restaurants being their test subjects. The experiment had some unexpected outcomes which she posted on her social media. In fact, they greatly surprised the residents of London, Ontario which is where the experiments were conducted and uncovered a fish fraud ring.

The Experiment

An active social media user, Dr. McDonald decided to document a class experiment involving fish DNA. She wanted her class to be able to positively identify different types of fish, which meant that they needed to collect samples from a variety of locations.

The biggest supplier of samples would be restaurants, specifically sushi ones. They regularly received new stock which meant her students just needed to eat out and grab a piece of fish for later.

The Testing Kits

Her students were excited by the prospect of actually doing something practical with the skills they had been learning. It would require specific testing kits for the fish DNA which would create a DNA sequence that they could then match to the barcode associated with the DNA from each fish and see if the two matched.

If the two sequences are different then it means they are not the same fish. It was an experiment that would involve a lot of fun and a whole lot of science which is just what Dr. McDonald’s students needed to get excited about biology.

Getting Organized

While the experiment itself was meant to be something fun, Dr. McDonald also wanted her students to learn the importance of labeling food and knowing what exactly it is they are putting into their bodies. Each piece of fish that was collected either from a restaurant or a grocery store had to be placed in a Ziploc bag and labeled with a permanent marker with exactly what it is.

A lot of people do not think about food allergies and intolerances which can have life-changing results if a person eats something they shouldn’t. Food safety would also be part of the experiment.

The Outcome

After the students had painstakingly collected samples, labeled the bags, and sequenced the DNA, the results were ready to be shared. Dr. McDonald had had an idea of what the results might be but she did not think the class had any idea the samples they had tested were most likely not what they thought they were.

Food is routinely packaged with unlisted ingredients or even marketed as a different food altogether. At one point cat meat was used as chicken in some Chinese food restaurants which caused quite the stir. Was something similar going to happen with the so-called fish?

Another Kettle Of Fish

As the results of the DNA tests were laid out, some startling revelations began to unfold. Dr. McDonald released fish updates on her Twitter to let the world know about what they may or may not be eating. The first test showed that the red snapper sample was actually the common and cheap fish, tilapia.

The second test had expensive Atlantic salmon actually test positive for being rainbow trout. These fish were different species altogether, but restaurants and grocery stores had marketed them as the more expensive fish knowing that their customers would not necessarily taste the difference but would pay for the fancy fish.

The Truth Will Come Out

Now it was time to look at two samples which were both supposed to be rainbow trout. The packaging said one was smoked and the other was fresh. The smoked fish turned out to be coho salmon and was probably smoked by the producer to change its appearance to look more like trout than salmon.

But DNA sequencing does not lie and the truth came out once more. The other sample was actually rainbow trout which restored a bit of faith in the class.

Another Positive Sequence

Two more samples of fish from local stores in town were selected and sequenced. One was for Icelandic Cod which had been certified as being that. All the students hoped that they had not been duped again, and luckily the certified fish was indeed Icelandic Cod. The Atlantic Cod that was also tested was not from the Atlantic but instead the Pacific. Another case of wrongful packaging had occurred.

At least this time they were both cod and not different species altogether like the trout and the salmon.

The Sushi Samples

Some students had noticed that they did not feel very well after eating at certain sushi restaurants which shall remain nameless. They decided to test the fish they were serving. One student selected a piece of red tuna which of course turned out to not be red tuna.

It was tilapia once again. Tilapia is a fish found almost everywhere and is incredibly cheap to farm and produce which is why it tends to show up in a lot of stores and restaurants.

Different Species

Two more sushi restaurants were put to the sequencing test with what they claimed were albacore tuna pieces. The students tested both and one came back as yellowfin tuna which is actually more expensive. The other came back as escolar.

The escolar was really concerning because it can actually cause digestion issues as it has a natural oil in it that humans cannot eat. That is why it is on the no-serve list in most countries.

Mystery Sample

Things took a turn for the weird when the final sample did not even sequence as a known fish. This was very confusing as it was supposed to be salmon but the DNA sequencing kept saying that it had “unknown bases.”

Dr. McDonald did not like the sound of that and decided that she needed to figure out what exactly this restaurant or grocery store was selling to the public. It could be harmful like the escolar.

Where Had It Come From?

It became necessary to figure out the origin of this mystery sample. Dr. McDonald thought the clue to solving the whole thing might be where it had come from. It turned out that it was a quick grab from a seafood counter.

The clerk thought they had selected the salmon that the student had asked for. It was painfully obvious that this unknown substance was definitely not the salmon that it was supposed to be.

A Positive ID

The class worked with Dr. McDonald to sequence the DNA alongside other types of DNA to see what exactly this mystery meat was. She thought that 500 base pairs would provide definitive proof of what she was beginning to suspect this was.

Once she made it to 200 pairs she had all the information she needed to announce to the class what the mystery fish was. And what a disgusting announcement it was, definitely not something anyone should be eating.

A Startling Revelation

So what was this unknown substance? Body louse. It seemed like maybe this was a fish sample at some point but it had been completely covered in body louse rendering it almost unidentifiable to the DNA sequence tests. To make matters worse this was not an inexpensive packet of fish picked up from your everyday supermarket.

A student had gone and purchased an expensive fillet of salmon in the hopes that it would actually be what it was supposed to be. The worst part: the student’s family had actually eaten the rest of the fillet.

Shock And Awe

There were a lot of different responses from the students when they realized that they had not been eating what they thought they were. Some students were disgusted that grocery stores and sushi restaurants were substituting fish for potentially dangerous ones.

Dr. McDonald was happy that the experiment proved her hypothesis that not everything is what it seems when it comes to food labels. Only two of the nine samples tested were actually what they said they were.

Raising Awareness

The intention of the experiment was to educate about food labeling and safety, not call out restaurants and grocery stores for lying to their customers either knowingly or unknowingly. Dr. McDonald pulled out the old phrase, “You are what you eat.”

Except, in this case, it seems that nobody actually knows what they are eating which is a huge problem. She recommended to her students and her Twitter followers to only buy certified products.

Can’t Stop, Won’t Stop

Just because the fish tested in her experiment turned out to not be what it was supposed to do not stop her from eating fish in the future. Dr. McDonald actually admitted that she went home and cooked up some fish for dinner after seeing the sequencing results.

She said that the experiment did not tell her anything new and she already ate fish from places that she believed provided a certified product.

Trust Is Key

None of this was meant to be a scare tactic to get students to become vegetarians or stop going to sushi restaurants. Dr. McDonald really just wanted to raise awareness and make her students more conscious consumers.

Don’t stop yourself from enjoying sushi, instead, ask yourself if the restaurant you are going to is one that you believe you can trust to serve you the freshest quality fish. And if you are in doubt, don’t eat there.

Not The Consumer’s Fault

A fish like a tilapia is very easy to change the color of and the taste as it tends to absorb whatever is put on or into it. Dr. McDonald just wants people to be wary about any products that could harm them if they have allergies and think they are eating one thing but their reaction to it tells them it is something else.

If you eat a fish that has a red tinge to the meat, it may not actually be salmon but a white fish that’s been dyed.

Going Viral

As Dr. McDonald tweeted the entire experiment, her story was quickly picked up in numerous threads and other people shared their own findings. Some people even decided that they feel they should conduct DNA experiments on the fish from their favorite sources to check if they are being fooled as well.

The experiments are not over for this doctor, fish was just the beginning now she wants to test shellfish and canned products to see what companies are lying on a big-scale basis.

Restaurants May Be Surprised

It is pretty unlikely that the restaurants are selling fish knowing it is actually a different one. Cheap sushi places tend to just use whatever their food supplier gives them while expensive ones will use certified fish that has been locally sourced or from specific fish markets for quality control.

This means that you are probably getting what you pay for, so if you are concerned about the quality you may want to “shell” out a bit more.

Anger

As the experiment continued to circuit around various social media sites, people began to get more and more upset over Dr. McDonald’s findings. How could grocery stores and restaurants be serving fish like escolar which could cause major health damage?

But the experiment had its intended result: it raised awareness. People will now think twice before eating a fish of unknown origin which could save them from eating something they would rather not, like body louse.

Fishery Regulations

The fact that Dr. McDonald and her class was able to show that seafood is largely unregulated in Canada showed the world that countries need to take a look at the seafood production industry. People do not know what they are eating more than 50% of the time the study proved.

It seems like a lot of the fish that is sent to grocery stores is mislabelled and a lot of companies may be doing this to make extra money at the expense of the public’s health.

The ‘Sustainable” Label

While we may never know exactly what fish we are eating unless we decide to run a DNA sequencing test there are a couple of things you can do to make sure you are getting what you want. If you look for ‘sustainable’ fish products then they will actually be what they are labeled as most of the time.

Just be wary of a lot of grocery store fish if it is quite cheap. Let this story be a word of warning but in no way a scare tactic. Keep eating fish, just think about where it is coming from!