Demystifying Immortalized Cells

Yesterday, an article ran in Bloomberg about immortalized cells in relation to cultivated meat. While we appreciate the reporter trying to shed light on the topic, there are some points we felt worth explaining and clarifying.?

First, what does it mean for cells to be ‘immortal’? This isn’t actually a scientific term, but is really just shorthand for cells that can keep growing for longer than is normal for their cell type. Most animal cells can only double 40-50 times before they stop growing; however for cells to be developed and then used in a manufacturing process, you generally need them to be able to double at least 100 times. “Immortal” cell lines usually just means cell lines that can grow for this kind of length of time—an essential step if we want to create a new food system, where we can safely and humanely produce all the meat that a growing population needs and wants, without destroying the planet along the way.?

The article points out that cancers have mutations which also cause them to be immortal, and uses this to raise a specter of food safety for cultivated cells that have been immortalized—despite there being absolutely no basis for any actual concern (as the article itself highlights). Importantly, a cell being ‘immortal’ doesn’t mean it is cancerous—most stem cells are immortal, for example, and certainly are not ‘cancer’. There are trees that can live for thousands of years and are functionally immortal; there are even immortal jellyfish that can regenerate their cells. However as the FDA has commented, it’s a moot point anyway, as you can’t actually catch cancer from eating animal cells: cancer is not ‘contagious’. It’s much more risky to eat conventional meats processed with nitrates, which is actually a known carcinogen.?

The bottom line is the fact that an animal cell is immortal doesn’t change its safety profile as a food at all—cultivated cells are not only safe to eat, they are in fact much safer than conventional meat, as they have much lower risk of bacterial contamination and zoonotic diseases (believe us, a cultivated meat factory is much, much cleaner than a slaughterhouse!).

(1) CLAIM: For decades, companies such as Pfizer Inc.and Johnson & Johnson have cultured large volumes of cells to produce vaccines…. Now the idea is that we might as well eat these cells, too.

(1) FACTS: Accurate. The idea of growing cells is not new, at least for medicine, research, and other applications outside of food.

(2) CLAIM: The three largest cultivated meat companies call their products (chicken) meat..And that’s 99.9% true. ...normal meat cells don’t just keep dividing forever. To get the cell cultures to grow at rates big enough to power a business, several companies…. are quietly using what are called immortalized cells, something most people have never eaten intentionally. Immortalized cells are a staple of medical research, but they are, technically speaking, precancerous and can be, in some cases, fully cancerous.

(2) FACTS: In order to make a large-scale transition of the meat industry to cultivated meat (which is essential if we want to provide the protein that people want without destroying the rainforest or throwing billions more animals into factory farming), we need to develop processes that can feed billions of people. Immortalizing cell lines is a key step towards this, as it means that cells from a single animal can go on to basically feed the world.?

Immortalizing cells doesn’t by itself fundamentally change the? safety profile in any way; and this is something that all cells are capable of (in nature most stem cells are immortal, and certainly are not ‘cancer’).

(3) CLAIM: You’d be better off worrying about the nitrates (linked with cancer) or fecal matter (a source of deadly infections) found in farm-raised meat. And cow tumors sometimes wind up in store-bought ground chuck, too. Of course, the facts might not matter much if ranchers or other players in the traditional meat industry felt threatened enough to declare a public-relations war. It’s all too easy to imagine misleading Fox News chyrons about chicken tumors and cancer burgers.

(3) FACTS: Accurate. What are communicable…are parasites, viruses, and bacteria that are all commonly found in poorly processed meat from many factory farms. Additionally, it has also been proven that ultra-processed meats (like hot dogs and? lunch meats) high in nitrates, and preservatives are, in fact, carcinogens.

(4) CLAIM: Even if your nouveau meat doesn’t cause cancer and isn’t exactly made from cancer, having to say so repeatedly will inevitably turn off a great many potential customers. As one executive in the field told me, with a dose of comic understatement, there’s a chance the whole thing really “might bother some people.”

(4) FACTS: We will only have to say so repeatedly if people keep bringing up false fears about the safety of cultivated meat… like this article does?

(5) CLAIM: Eric Schulze, Upside Foods vice president for global scientific and regulatory affairs, says his company stands by its FDA nod and its safety protocols. “Many of the inputs and processes we use have been used for decades or even centuries in food production,” he said in a statement. “Our product is as safe as the chicken you eat every day.”

(5) FACTS: Probably safer, in fact. "Normal" chicken is regularly recalled (salmonella and other harmful, even fatal, bacteria). However, cultivated meat comes from sanitized, stainless steel tanks, just like beer.?

(6) CLAIM: Despite the informal scientific consensus around the safety of immortalized cells, there just aren’t any long-term health studies to prove it.

(6) FACTS: While it’s true that there are no long-term studies around eating immortalized cells (*sensationalism - this would be impossible given how new the space is*), this does not change the fact that they’re just animal muscle cells. People have been eating animal muscle cells for millennia without a problem. Immortalized cells just allow us to grow those same cells in a better way.?

(7) CLAIM: Cultured meat companies induce these changes via genetic modification or by forcing normal cells to reproduce until some of them mutate. The resulting cells can divide forever, defying the normal limits of growth. This also makes them unmistakably more like cancer cells than they used to be, says Robert Weinberg, the pioneering Massachusetts Institute of Technology biologist who proved cancer is a genetic disease in the 1980s. “If a cell is immortalized, that implies that it’s already completed one of the prerequisites to become a cancer cell.”?

(7) FACTS: While being immortal is one of the prerequisites for a cancer cell, there are also cell types (like many stem cells) which are immortal—and certainly *not* cancer.?

The process for making cultivated meat starts with a normal cell from a healthy animal muscle. That is then developed into a cell that is only able to grow in a bioreactor to produce meat cells that are completely safe to consume. The cells stop growing and die as soon as they are removed from a bioreactor.?

(8) CLAIM: In a footnote, the agency (FDA) concluded that even fully cancerous cells would be safe to eat because they stop growing after they leave the bioreactor, and cooking and digestion will break them down harmlessly. “We did not identify any properties of the cells as described that would render them different from other animal cells with respect to safety for food use,” the FDA said.

(8) FACTS: Fact! A cell being immortal doesn’t mean that it’s cancerous—but regardless, any cultivated meat cell is completely safe to eat. Any cultivated meat product in the US has to go through a rigorous approval process with the FDA and the USDA ensuring that they are safe.???

We’re proud to be making meat that the world can depend on—because we can cultivate it from cells, enabling us to make delicious burgers without needing to worry about deforestation or animal welfare. Immortalization is just part of how we get there. And that’s something to be excited about!?