Sushi is one of my favorite foods. I love the colors, tastes and varieties. When it comes to sushi, tuna is the most popular ingredient. I like it raw, cooked, dipped, sliced, with Wasabi, and even seared with black sesame seeds. Tuna is best when it’s minced and mixed with Sriracha sauce or served fresh and sliced (as in Tuna Sashimi). But how fresh is your Tuna? And, would you be able to tell just by looking at it?.
Most people judge a book by its cover, and they judge Tuna just the same. People will say that a deep red or pink color on Ahi or Yellowfin Tuna is the best way to tell if it is fresh if you ask them. However, as someone who has caught tuna, I know that a steak will turn chocolate brown about an hour after being cut. So I researched further into commercial Tuna and found out something interesting.
The Tuna industry has been keeping a little secret from us. That deep red tuna steak you see in the market might not be what you think it is, and it might not even be fresh! It looks like the Ahi Tuna business has turned to Chemistry to sell their goods. The beautiful red tuna steaks you see at the fish store or in your neighborhood sushi restaurant are not really red. The carbon monoxide was pumped into the fish to make it red and keep it that color. This is similar to how tomatoes are turned red by pumping them with ethylene gas. The carbon monoxide turns the normally chocolate-colored Tuna a more palatable red. You can test this yourself by putting a piece of chocolate tuna next to your car’s tailpipe and seeing the color change. WARNING: Do not attempt to eat the fish if you have exposed it to your cars exhaust fumes. There are other harmful chemicals in your car’s exhaust fumes that you don’t want to eat! This is just a test to show that carbon monoxide will change the fish’s color.
The FDA and its Canadian counterpart say that adding carbon monoxide to tuna is against the law in North America. However, as most Ahi Tuna comes from the Pacific, Asian processing facilities ship the fish already treated. There are no laws in Asia which prohibit the use of carbon monoxide to treat fish.
Is it safe? I was not able to find any information on the effects of eating treated Tuna. But Its only common sense to assume that natural is better.
Regarding how fresh it was, I left a piece of treated tuna at room temperature for 24 hours. It was obviously bad, but the color stayed the same! It was a nice deep red that turned pink after a while. If this piece was behind glass at the fish market, I certainly would have purchased it. It never turned chocolate. If you can’t tell how good the tuna is by how it looks, how can you? Luckily, your nose is your best tool. You should judge Tuna by its smell, texture and taste. It should have a pleasant fishy smell, and firm flesh. Last but not least, it should taste good! The fact that it’s chocolate-colored is just what any lean protein should do when it comes in contact with oxygen and the oxidizing
What’s wrong with a piece of natural Yellowfin Tuna that is chocolate brown? That’s just its natural color. People are so used to commercially processed tuna that they won’t buy the natural stuff, which is the only reason most stores won’t sell it. So fish markets are forced to continue importing and selling the treated Tuna. I have nothing against a nice red fish, but when I’m being sold something, I want it to be honest, which is why I wrote this article. Recently, I’ve been enjoying chocolate, organic South Pacific Ahi Tuna in my Japanese dishes. I will keep using this product and tell my clients where it comes from and what it tastes like. I simply prefer a more natural food over a processed food. Next time you go shopping for tuna, don’t look at the color. Instead, look at the quality. Which piece of tuna smells, tastes, and feels the best should be the one you choose.
Tuna is one of the most popular fish in the world. It’s versatile, nutritious, and tasty. But with growing concerns over sustainability and mercury levels, is grey tuna safe to eat?
I took a deep dive into the details on grey tuna to find out Keep reading for everything you need to know about eating this fish,
An Overview of Grey Tuna
Grey tuna refers to several species of tuna that have a silver-grey color. The most common are:
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Albacore tuna (Thunnus alalunga) This is what’s usually canned as “white tuna.” It’s found in temperate and tropical oceans worldwide
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Yellowfin tuna (Thunnus albacares): The second most caught tuna species globally. It has a more yellow hue than albacore.
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Bigeye tuna (Thunnus obesus) A large predatory fish found in warmer waters. It’s similar to yellowfin but with larger eyes.
So when you see “grey tuna” on a menu or at the fish counter, it’s likely one of those three species. They share many traits like nutrition, taste, and texture.
All tuna are fast-swimming fish with torpedo-shaped bodies. Their meat tends to be firm with a dense, meaty flavor. Of the main edible tuna types, grey varieties are moderate in fat content, making them a leaner choice.
Evaluating the Safety of Eating Grey Tuna
Next, let’s go through the main safety factors to weigh when eating grey tuna varieties like albacore, yellowfin, and bigeye.
Mercury Levels
Like many large predatory fish, tuna contain mercury. The heavy metal builds up in their tissues as tuna eat smaller contaminated fish.
But mercury levels vary widely depending on the species, size, and location caught. Grey tuna generally have moderate mercury compared to other tuna:
- Albacore: 0.32 parts per million (ppm) average
- Yellowfin: 0.31 ppm
- Bigeye: 0.45 ppm
For perspective, canned light tuna has about 0.12 ppm. The FDA recommends limiting fish with over 0.5 ppm.
Pregnant women and young children are advised to avoid fish with over 0.3 ppm like albacore. But for most adults, moderate intake of grey tuna is considered low risk.
To cut down on mercury, choose smaller grey tuna under about 30 pounds. Larger, older fish accumulate the most mercury over their lifespan.
Sustainability
Some grey tuna populations are overfished or declining, while others remain healthy. Here’s a quick look at the sustainability of key species:
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Albacore: Populations in the North Pacific and North Atlantic are generally sustainable and well-managed under quotas.
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Yellowfin: Overfished in the western and central Pacific but abundant in the eastern Pacific and Indian oceans under sound management.
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Bigeye: Also overharvested in parts of the Pacific but not in the Atlantic and Indian oceans.
Seafood guides consider all three species a “good alternative” or “better choice” with some concerns. For best sustainability, choose troll/pole caught rather than longline.
Parasites
Tuna and other saltwater fish can sometimes carry parasites. In tuna, these are often anisakid nematodes (worms).
They rarely pose a risk to humans. But if ingested alive, some parasites can cause symptoms like nausea, cramping, or intestinal issues.
To kill any parasites, grey tuna should be frozen to -4°F (-20°C) for at least 7 days before eating raw or undercooked. This freezing treatment is standard practice for sushi restaurants.
Cooking tuna to an internal temperature of at least 145°F (63°C) also destroys any potential parasites. So thoroughly baked, grilled, or fried grey tuna is safe from parasites.
Freshness and Foodborne Illness
Like any type of fish, grey tuna can cause food poisoning if not stored and handled properly. Signs of spoiled tuna include:
- Bad odors
- Slimy texture
- Discoloration or mold growth
- Rancid or “off” taste
To avoid getting sick from eating grey tuna:
- Purchase tuna that is refrigerated or flash frozen
- Check the packaging for damage or stains
- Verify the expiration or sell-by date hasn’t passed
- Make sure refrigerated tuna is cold to the touch
- Use frozen tuna within 2-3 months
- Thaw frozen fish in the refrigerator, not at room temperature
- Refrigerate fresh tuna right away and use within 1-2 days
- Cook tuna within 1-2 days of thawing
- Discard any tuna that has an off smell, color, or texture
Taking these simple precautions helps prevent foodborne pathogens from growing.
Health Benefits of Grey Tuna
Beyond food safety, eating grey tuna varieties can also provide excellent nutrition:
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High-quality protein: A 3 ounce cooked portion contains about 25 grams of protein. Tuna is a complete protein with all the essential amino acids.
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Heart-healthy omega-3s: Grey tuna is rich in anti-inflammatory omega-3 fatty acids like EPA and DHA.
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Key vitamins and minerals: Tuna provides B vitamins, potassium, selenium, vitamin D, and other important nutrients.
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Low mercury: Albacore, yellowfin, and bigeye are moderately low in mercury compared to other fish.
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Lowers risk of CVD: Research shows tuna intake is associated with lower rates of heart disease and stroke.
The beneficial fats and nutrients in tuna support brain health, immune function, and overall wellness. It’s a nutritious choice as part of a balanced diet.
How to Choose, Store, and Prepare Grey Tuna
Here are some final tips for choosing quality grey tuna, storing it safely, and preparing it deliciously at home:
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Look for tuna with bright color, shiny skin, and no dark marks. Make sure frozen tuna has no freezer burn.
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Smell tuna before buying. It should never smell fishy or ammonia-like.
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Keep fresh tuna very cold, ideally below 40°F. Use within 1-2 days. Frozen tuna stays fresh for 2-3 months.
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Thaw frozen fish gradually in the fridge. Don’t refreeze raw tuna after thawing.
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Cook tuna to 145°F or until the flesh is opaque and flakes easily with a fork.
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Grill, bake, pan sear, or broil for easy, healthy meals. Add flavors like garlic, lemon, herbs, etc.
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For sushi or other raw preparations, ensure tuna was frozen to kill parasites.
The Bottom Line on Grey Tuna
So, after reviewing the facts, is grey tuna safe to eat? For most people, yes – in moderation. To minimize risks:
- Choose sustainable sources like troll/pole caught North Pacific albacore
- Eat a modest portion once or twice per week
- Avoid if pregnant or feeding young children due to mercury concerns
- Make sure raw tuna was properly frozen or cook thoroughly
- Store properly and verify freshness before consuming
With those precautions, grey tuna like albacore, yellowfin, and bigeye can be a nutritious, safe addition to your diet! It provides excellent protein, healthy fats, and vital nutrients with relatively low mercury risk.
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FAQ
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