All this angst over "pink slime" has made one thing clear: We don’t always know what we’re getting when we bite into a big juicy burger.

Which leaves unanswered some of the most basic questions in the debate over what the meat industry calls lean finely textured beef, a processed meat filler that experts say has found its way into much of the ground beef consumed in the United States.

But as a professional eater, I needed to know two things: What does this stuff do to the taste and texture of ground beef? And how can consumers know when they’re eating it?

Neither answer came easily, the former because of the sheer volume of beef I needed to eat, the latter because of the rather opaque way ground beef is made.

For schools, that opacity began to clear Thursday, when the U.S. Department of Agriculture announced that as of the fall the National School Lunch Program will allow districts to choose ground beef that does not contain the product. Previously, it was difficult for schools to know whether the beef they bought from the feds had it or not.

That’s because pink slime — no matter what you call it or what you think of it — really is made from beef and therefore doesn’t need to be listed as a separate ingredient.

But Thursday’s announcement doesn’t do much for the average consumer.

At the grocer, a steak is a steak, and it is nearly always labeled by the cut of beef it’s from. There was a time when ground beef was similarly labeled and you knew at least roughly what part of the animal you were getting. And though some packages still indicate "ground chuck" or "ground sirloin," today most is labeled simply as "ground beef."

Most consumers don’t care. They’d rather focus on another part of the label — the fat percentage. And producers don’t care. It has made it easier for them to take a more amalgamated approach to ground beef, using whatever cuts they want or have without worrying about spelling it out.

Now introduce lean finely textured beef, and the meat picture is further muddied.

The product is made from bits of meat left over from other cuts. It’s heated and spun to remove the fat, then compressed into blocks for mixing into conventional ground beef. Because it’s so lean and inexpensive, producers often mix it into fattier meat to produce an overall leaner product.

That means two packages labeled "ground beef 80 percent lean" may look and sound the same but be composed of different meats. One could be unadulterated ground beef made from cuts of meat containing 20 percent fat. The other could be made from poorer quality — much fattier — meat but cut with and made leaner by pink slime, a term coined by a federal microbiologist grossed out by it and now widely used by critics and food activists.

How do you tell the difference? For the most part, you don’t.

"You can’t differentiate beef from beef," said Jeremy Russell, a spokesman for the National Meat Association, which represents processors, suppliers and exporters. "Talking to your retailer would be the only way."

So that’s what I did. But it got me only partial answers.

At grocer No. 1, the folks behind the butcher counter were able to show me one brand, a pricy "all-natural" ground beef that did not contain the meat filler. But for the many other and far less expensive varieties of ground beef? They had no way of knowing.

Grocer No. 2 presented the opposite problem. The workers there found one brand that definitely did have the pink stuff, but they couldn’t say whether any others did or didn’t.

And don’t be fooled by the "all-natural" beef label at store No. 1. That term is unregulated, so it doesn’t really mean anything. At another store, another brand of ground beef could be similarly labeled but still contain the meat filler.

But the term "organic" is regulated, and that provides a clue. If you can find it — and are willing to pay the price — ground beef labeled organic cannot contain lean finely textured beef.

Despite the odds, I had lucked out. Between the two grocers, I’d managed to identify two packages of 85 percent lean ground beef, one with pink slime and one without. Time to taste.

By label alone, it was clear we were talking different beef demographics. The pink slime-free product bragged that it was minimally processed and that the cows had been raised without antibiotics, growth hormones or animal byproducts in their food. Price — $5.99 per pound. The pink slime version? Just a minimalist "compare and save." Price — $3.09 per pound.

Outwardly, they seemed the same: They smelled the same, and they looked basically the same, though the pink slime sample was slightly lighter in color. Until you touched them. The all-natural sample was slightly fattier to touch. That seemed odd, since both products should have the same fat content.

For the taste test, I kept it simple and pure. I formed a half-pound of each ground beef into a thick burger patty, adding nothing to the meat. And though I prefer my burgers on the grill, I decided to fry these in a skillet because it’s easier to control the cooking, ensuring both would be cooked to the same degree and under the same conditions.

I added nothing to the pan. Meat this fatty generally bleeds out a robust amount of grease, so I wasn’t concerned with sticking. That was my second surprise. The pink slime patty released very little fat during cooking. The other patty gave off two or three times as much.

About 5 minutes per side, and I declared them medium-rare. After giving them a few minutes to rest, I seasoned them lightly with salt and pepper, then cut in.

First, the unadulterated burger. The aroma was luscious. The meat was juicy, tender and nicely seared. Where I’d cut, juices slowly dribbled out onto the plate, collecting in a pool. The taste was savory and meaty, with big beefy flavor. The chew had just the right texture, substantial but giving. Basically, everything you would want in a burger.

The pink slime burger also was perfectly seared and drew me in with an equally alluring aroma. But no juices collected on the plate. Or dribbled out. Or were apparent in the meat in really any way. The taste was — OK. I took another taste of the first burger, then back to the pink slime burger.

It was not bad. But nor was it good. It was flat. I added more salt. No. It was simply one-dimensional.

And then there was the texture. Unpleasantly chewy bits of what I can only describe as gristle, though they were not visible, seemed to stud the meat of the pink slime burger. The result was a mealy chew that, while not overtly unpleasant, didn’t leave me wanting another bite.

Of course, I did take another bite. In the interest of good journalism, I ate both burgers entirely. And then I felt sick. I’m confident that has nothing to do with slime of any sort.

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Freelance food writer Michele Kayal in Washington contributed to this report.