Science

What Is Meat Glue? Ask Paul

The truth about transglutaminase.
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Published Nov. 23, 2022.

Emily asked, What is meat glue? Is it as gross and dangerous as it sounds?

What Is Meat Glue?

“Meat glue” is the rather unappetizing nickname of a product containing the naturally occurring enzyme transglutaminase. This enzyme has the power to link protein molecules to each other. Our bodies manufacture and use transglutaminase to build skin, heal wounds, and many other processes.

In the food world, transglutaminase is manufactured by microbial fermentation and is sold under the brand name Activa (not to be confused with the yogurt Activia). It’s formulated as a powder that can be added to food in order to, as the manufacturer’s site says, “help create unique food concepts.”

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Activa is used in food manufacturing to improve the texture of many processed products, like baked goods, cheeses, and tofu, but it gets its nickname from its common use in meat-based foods such as sausages, fish cakes, and chicken nuggets: When you want little pieces of meat to form together into a pleasant-textured whole, meat glue is your friend.

How Do Home Cooks and Restaurants Use Meat Glue?

Like other modern products and techniques, such as xanthan gum or sous vide, transglutaminase has made its way from commercial food manufacturing into the hands of innovative home and restaurant cooks. It allows for cool effects, such as gluing bacon strips to lamb chops or, famously, making spaghetti out of shrimp meat.

But it’s also extremely good at less stunt-y tasks, like quietly improving the texture of sausages and dairy desserts, if you are inclined. But it’s gotten a bad reputation over the years, perhaps because of its nickname, or just because it is unquestionably a somewhat weird item. Let’s look at some of the rumors about meat glue.

Is Meat Glue Toxic?

Our bodies are full of transglutaminase already. And transglutaminase is denatured when it is cooked, so it's no longer an active enzyme by the time we eat it. It is a protein, and our stomach acid digests protein very well.

Is Meat Glue Made Out of Animal Blood?

Various sources on the internet conflate transglutaminase with a different product, derived from blood plasma, that was banned in the EU in 2010. Activa-brand transglutaminase is produced by bacterial fermentation, not harvested from animals (which would be prohibitively expensive, among other problems).

Is Meat Glue Dangerous?

Transglutaminase can be used to glue two pieces of meat together so that their surfaces are no longer on the outside. But the surface of meat is where bacteria live, which is why were usually careful to cook it fully.

That’s a food safety risk if the interior of transglutaminase-treated meat is cooked rare, so for safety, meat processed with transglutaminase should always be treated as though it were ground meat. Either cook the interior to 160°F, or only serve it to people who are comfortable eating foods like beef tartare or other raw meat.

Is Meat Glue Used in Illegal Ways?

There is a spectre that commonly gets raised of unscrupulous butchers or restaurants using transglutaminase to commit fraud: taking cheap scraps of meat, gluing them together to create Franken-steaks, and selling them for a high price.

That would be difficult to pull off, because glued-together meat has distinct visible seams, and it does not cook or chew like a steak. There don’t seem to be any recorded cases of it having actually been done, so it seems very much like an amusing urban legend.

Ask Paul Adams, senior science research editor, about culinary ambiguities, terms of art, and useful distinctions: paul@americastestkitchen.com

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