Which big brand names are behind Trader Joe's products?

Ever thought the perfectly crisp chocolate-chip cookies at Trader Joe's tasted a lot like the ones from Tate's Bake Shop? And that the packaging is, huh, remarkably similar?

Maybe that's because the well-known brand bakes the cookies for the national supermarket chain.

Or, maybe not.

See, Trader Joe's doesn't have a factory where it makes its own products. Instead, the privately held grocery chain based in Monrovia, Calif., sources items from companies specializing in generic products, and, in some cases, from well-known brands. Then they slap on the Trader Joe's label.

"There are companies out there that make only store-brand products," says Phil Lempert, the grocery-retailing expert who calls himself the Supermarket Guru. "It's not as if we can assume Skippy peanut butter is making the Trader Joe's peanut butter. It could be, or it could not be."

In an effort to get customers to develop loyalty to its own brand, Trader Joe's is incredibly secretive and closely guards the source of some of its signature products. Lempert says this is industry practice with all major grocery stores, whether Whole Foods or Safeway, which both have their own lines of generics.

Similarly, the big brands don't want consumers to have this information, because Trader Joe's sells its products at discounted prices. If you were, say, Frito-Lay and quietly baking Trader Joe's pita chips, you wouldn't want people to know the TJ's generic is the same as your Stacy's pita chips that cost more. (We're not saying Frito-Lay makes Trader Joe's pita chips, but that said, they do taste incredibly similar to the Stacy's brand.)

It's really nobody's business," says Lempert. "It's a retailer working with a manufacturer to produce a product with the best quality they can at the best price they can, and they hold those relationships near and dear."

Lempert adds that even if a brand name is making a generic product, they're very often using a different recipe than the products sold in other stores.

Trader Joe's can keep its prices down because it doesn't spend big marketing dollars on advertising beyond its own Fearless Flyer, nor does it have a complex coupon program. And buying directly from manufacturers keeps costs low as you're cutting out the middleman.

Consumers are all about trying to guesstimate Trader Joe's brand relationships based on packaging, ingredient lists and taste. Is Naked making Trader Joe's mango juice? Is Stonyfield providing the yogurt smoothies? Is Trader Joe's buying its canned tomatoes from Muir Glenn?

We reached out to Trader Joe's to ask whether they could answer any of these questions, and not surprisingly, they said they couldn't comment.

"As a privately held company, we do not discuss our business strategy, financials or our suppliers," the company wrote in a statement.

We also contacted a few of the big brands most likely to be working with Trader Joe's, and all of them said they couldn't discuss the matter, save Annie's, which said the widely held assumption that its company is making TJ's mac 'n' cheese is false.

"We only label our products as Annie's," a statement from the company reads.

Well, that dispels one big rumor, but what about the dozens of others?

In the gallery above, we share Trader Joe's products that either taste or appear similar to big-brand counterparts. Tell us in the comments, do you think they're the same?

Amy Graff is a digital editor for SFGATE. Email: agraff@sfgate.com