If you’re a fitness  and nutrition nerd, you’re long past the grade school days of willingly eating glue, paste, and other pseudo-edible adhesives, but there’s a decent chance you’re still eating an entirely different kind of glue unknowingly. Maybe even on a regular basis. I’m talking about meat glue, also known as transglutaminase, which restaurants and food producers use to create “steaks” out of “glued-together” stew meat, add body to dairy products, make imitation crab, improve processed meat  mouth feel, to name a few. A video exposing the “secret” of meat glue has been making the rounds of the various health circles, and more than a few readers have asked me about it. Here’s the video in question, taken from a recent Australian expose:
With that out of the way, what exactly is transglutaminase, and should you be worried about it?
Transglutaminase is an enzyme, produced either by bacterial cultivation (via fermentation of plant extracts) or from the coagulation factor in porcine and bovine blood, that bonds proteins together. Once it’s been cultivated or extracted, transglutaminase is dried into a powder that can be easily applied to a number of products, including
Reconstituted steaks, fillets, roasts, or cutlets – Meat glue is added to disparate chunks of meat (like cheap stew meat, chunks of chicken – any meat, really) and rubbed in. The chunks are compressed together and left to cool; after several hours, the meat pieces have formed insoluble bonds made of protein polymers. You can usually pull apart the “steak” to reveal the composite pieces, but take a quick glance and you’d never know it was cheap stew meat glued together. To most consumers, the resultant reconstituted “steak” is indistinguishable from a real slab of meat once it’s cooked, but a skilled meat glue artist can create “steaks” that fool experts – even when they’re raw.
Sausages, hot dogs, and other processed meats – Transglutaminase is added to provide uniform texture to processed meats. The “bits” become smooth and seamless. Imagine Oscar Mayer balogna and you’ll get the picture.
Fish balls, chicken nuggets, and other examples of deliciousness – Makes all that chicken viscera go down smooth.
Novel culinary creations – Some chefs are getting pretty creative with meat glue. One guy in NYC, for example, uses meat glue to make flourless noodles out of shrimp ! I’d eat that.
On its face, meat glue sounds awful. I don’t think I have to explain why. It’s just repulsive on a visceral level. Furthermore, it’s generally used to make some pretty awful foods. We can’t really blame the transglutaminase for that, though. It’s not the meat glue that makes chicken nuggets a bad idea; it’s the hydrogenated vegetable oil  in which they’re fried and the refined wheat breading in which the “chicken” is encased. I suppose you could call meat glue an enabler, but it’s not the offending party. But is it itself bad for you?
The FDA has deemed it “generally safe” (what confidence!) and there’s got to be something in PubMed that justifies their conclusion… right? Well, I searched far and wide and while there is a ton of research on culinary and industrial applications of transglutaminase, there was nothing about the safety thereof. Nothing good, nothing bad. It simply wasn’t there in any direction.
Most of it was stuff like the paper showing that microbial transglutaminase increases the sensory appeal  of chicken sausages made from various chicken parts across several parameters, including texture, water retention, and appearance. Note that researchers failed to mention taste. I take this to mean meat glue made the texture of the sausages  uniform (so the average consumer doesn’t know what they’re eating) and improved their plumpness (added water weight). In other words, meat glue allows consumers to eat meat paste without inconvenient thoughts of dead baby animals obstructing their carefree chewing and swallowing. So, it may be used in a misleading way, but there’s nothing here about negative health effects, either from eating the glue itself or caused by it.
As I see it, the real danger with glued meat is in the uneven heating of reconstituted steaks made up of random pieces of stew meat. See, most reasonable people eat their steak at or below medium doneness. I’m a rare-to-medium-rare man myself, and with a real slab of animal, going rare, medium rare, or medium usually isn’t a problem. The exterior – the part that’s potentially been exposed to dangerous bacteria – is cooked or seared. The inside may be undercooked or even bloody, but the inside of a piece of real meat doesn’t get significant bacterial exposure, so there’s little to no danger. But “steaks” aren’t one piece of meat. They are made of multiple pieces of meat, each with its own history, its own exterior, and its own collection of bacteria . If you treat a glued together “steak” like a regular steak  and eat it below medium, you’ll be eating some undercooked meat exteriors. Unless you braise that fake steak or burn it to a crisp, there’s no way you’ll know if all the component pieces have been sufficiently cooked. And if you’re ordering steak at a standard restaurant, you have no control over how it’s handled – or even what you’re really eating. Bonded meat isn’t necessarily unhealthy, but cooking it well requires a little more attention to detail, and in a restaurant, especially your garden variety chain restaurant, the cooking is entirely out of your hands.
Beyond that, it’s the deception that really bugs me. I think a lot of the outcry against transglutaminase can be explained by that: people don’t like being deceived, especially when there’s money on the line. If I buy a filet, it had better be an actual filet (singular), not a random assortment of trim and stew cobbled together and sprinkled with a bonding enzyme. Luckily, I know the meat I buy is real and whole, as does anyone who buys direct from farmers or from trusted butchers and meat counters, but not everyone has the inclination or ability to source meat from the source.
If you’re worried that the meat you buy contains transglutaminase, you can do a few things to avoid any potential complications:
- Do what the guy in the video did and gently tug on your meat. If your steak comes apart, it’s probably “steak.” It’s probably best to perform the tug test before you pay for the meat, and most meat counters/butchers will allow you to inspect what they sell.
- Just cook it thoroughly. I would advise against cooking your “steak” like a steak until well done, because, well, that just ruins meat, but a nice braise, crockpot stew, or soup would all work. Remember: it is meat and it is edible.
- Ask. Ask your butcher, your meat supplier, or your waiter if the meat contains glue. They should know, and if they don’t (or if they’re unwilling to say), order something else or go elsewhere.
Honestly, though, I don’t think transglutaminase in and of itself represents a big problem. It might come in otherwise unhealthy or suboptimal foods (processed meat, chicken nuggets, etc.) and it might expose you to bacteria if undercooked, but I don’t think it’s anything to lose sleep over.
What say you, readers? Where do you stand on meat glue?