Outcry grows over questionable “vitamin tuna” treatment process

The increasingly common process is used to make low-grade tuna appear to be of a higher quality through a mixture of chemicals and gas treatments that often go unlabeled.
Tuna bathed in beet juice as part of a process used to improve the appearance of lower-grade fish.
Tuna bathed in beet juice as part of a process used to improve the appearance of lower-grade fish
10+ Min
A whistleblower video sent to SeafoodSource showing the vitamin tuna manufacturing process.

Yellowfin and bigeye tuna steaks and loins sold across the United States – and likely Europe and other markets – are increasingly probable to be tainted with unlisted ingredients, including citric acid, beet extract, and sodium, according to three global seafood executives.

Up to 60 percent of yellowfin tuna steaks exported from Vietnam undergo a process through which they are injected with a saline solution and then bathed in a mixture of beet juice, paprika, and additives like sodium ascorbate and ascorbic acid. After this, they are treated with carbon monoxide or a tasteless, or clear, smoke. The process vastly improves the coloration of lower-grade tuna and gives the product an added water weight that can increase its value by 15 to 20 percent, the executives said.

“More and more, it's becoming common practice, specifically for companies using lower-grade raw material like purse-seine tuna,” Sea Delight President Cesar Bencosme told SeafoodSource. “As far as we’re aware, none of these ingredients are illegal to use; you just need to declare it on the label. That’s not really being done. We strongly recommend end users add sodium, nitrate, and citric acid to their internal testing protocol for tuna items."

Bencosme said Sea Delight, a major importer of frozen and fresh tuna based in Coral Springs, Florida, U.S.A., has raised the issue publicly because the company has an obligation of transparency to uphold. 

“I would even say even some of the smaller importers might not even know they're getting tuna treated with citric acid since they don't have the ability to go overseas and get more information or know what their suppliers are doing,” Bencosme said. “It’s about being transparent. If you're going to do something like this, sell it for what it is.”

Miami, Florida, U.S.A.-based importer Seafarers is also speaking out about what it has termed “dishonest methods” that mask low-grade tuna “with a concoction of chemical compounds and gas treatments.”

“It's critical to distinguish between legitimate processes that preserve the authenticity of high-quality tuna and the alarming practice of treating subpar frozen tuna,” the company said in a statement. “Shockingly, our team in Vietnam has witnessed how various suppliers are engaging in a disturbing process involving soaking inferior thawed tuna in a mixture comprising sodium ascorbate, ascorbic acid, sodium tripolyphosphate (STPP), and sodium bicarbonate. These additives play a crucial role in increasing the weight of the tuna while maintaining desired moisture levels, resulting in a substantial net weight increase ranging from 12 percent to 18 percent, varying across different processing facilities.”

Moreover, according to Seafarers – which is one of the largest American importers of tuna – color additives like PROVIV 1200 containing beet juice concentration, salt, and paprika oleoresin, are employed to artificially enhance the appearance of these lower-quality tuna loins, misleading consumers into believing they are purchasing higher-grade products.

“The repercussions of these practices are dire. Despite a 41 percent drop in tuna exports to the U.S. during the first nine months of 2023, these misrepresented products are flooding the market, disrupting prices, and misleading consumers about the actual quality of the tuna they're purchasing," Seafarers said.

Seafarers President Willy Rosell said his biggest concern regarding what has become known as “vitamin tuna” for its use of ascorbic acid, or vitamin C, is that the safety and suitability of these products for human consumption remain in question.

“Consumers aren’t being told what’s in their tuna; even we don’t know what’s in it, and we’ve done lab testing,” Rosell told SeafoodSource. “People with allergies or who don’t want all that extra sodium are not being told that’s what they’re consuming. Besides that, it tastes very strange. I’m worried it’s going to hurt the reputation of tuna in the marketplace.”

Sea Delight said it’s mostly Vietnamese processors who are exporting “vitamin tuna,” estimating more than 25 percent of all yellowfin tuna exported from Vietnam has gone through the process. Because it can “easily equal 15 to 20 percent extra value” on every case due to the added water content, Indonesian, Thai, and Malaysian exporters are also beginning to adopt the practice, Bencosme said.

“If I'm buying something at USD 4.50 [EUR 4.18], my competitors who are buying the ‘vitamin tuna’ might be paying USD 0.50 to USD 0.60 [EUR 0.46 to EUR 0.56] less for that same shave cut,” he said.

Rosell said the tests Seafarers has conducted on “vitamin tuna” samples show 16 to 18 percent of its total weight comprises water and other additives. 

“It’s pricing the companies doing the right thing out of the market,” he said. “On top of that, they’re using tuna of very questionable quality. It’s very blackish in color; it looks like it was in a bad cooler on a boat for 20 days.”

Rosell said the vitamin tuna began infiltrating the market around 12 to 14 months ago, and since then, prices for frozen yellowfin tuna loins and steaks from Vietnam have come down to around USD 2.50 [EUR 2.32] per pound. But, Seafarers refuses to accept the vitamin tuna and pays USD 4.00 to USD 5.00 [EUR 3.72 to EUR 4.65] per pound.

“I'm worried for our company because our customers are seeing tuna for a lot cheaper than we offer it; eventually, we’re going to lose business due to this,” he said.

The senior executive of a Vietnamese tuna exporter is also worried about the future of her business. Yen Nguyen, an overseas manager for Hong Ngoc Seafood, said the process was pioneered around five years ago.

“We noticed a difference in the tuna; we could taste and smell something different. The color was pretty good, but the taste and texture was not there,” she said. “It was clear that something bad was going on, but we didn’t want to say anything until we did tests to prove [it].”

The company ran extensive tests over three years and posed as a European buyer, making inquiries to other Vietnamese tuna exporters about their processes. Over three years, Hong Ngoc was able to identify most of the additives, and through experimentation, it found the combination of citric acid, beet juice, and CO treatment – which is legal in the U.S. if labeled but illegal to sell in Europe – gives even bad-quality tuna a vibrant red coloration.

Nguyen estimates 60 percent of tuna exported from Vietnam and other countries now undergoes the vitamin treatment.

“Most importers just don't know about it,” she said. “But now, a lot of importers ignore the problem. They must know about it because it is so widespread, and word is out [about it].”

Nearly all tuna exporters have adopted the process, some reluctantly, because it’s what they need to do to remain competitive, Nguyen said.

“Of course on the business side, they want and need to have a profit, so they do what the customer wants,” she said. “We choose the harder way [of not doing it], and I sleep better at night, but it is making it really difficult for our company. I am afraid the whole tuna industry is turning in this bad direction.”

Nguyen said she has contacted the U.S. FDA ...


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