It started with your shoes, then your water. Now the TSA wants your snacks.

They came for your laptops. And for your liquids, and your shoes. Now, the Transportation Security Administration is coming for your snacks.

Passengers at airports across the country are reporting that increasingly TSA agents are instructing them to remove their snacks and other food items from their carry-ons and place them in those ubiquitous plastic bins for separate screening.

It's not part of agency's standard policy, according to TSA spokesman Mike England. It's simply a recommendation issued by the agency last year to help speed the bag-check process. Screening supervisors at airports have the discretion to decide whether, and when, to demand passengers proffer up their pretzel packs for a solo trip through the X-ray machine.

But the "recommendation" appears to be gaining steam and moving rapidly into the territory of de-facto protocol, according to travelers who have received snack-related notices from their airlines, and who have been informed by rank-and-file TSA screeners that the snack checks are now standard practice.

"He was just like, 'Sorry. This is a new policy. This is what we're doing now,' " Anny Gaul, 33, said of her recent interaction with a TSA agent at Baltimore-Washington International Airport.

Gaul, a frequent traveler, had never heard such instructions before while waiting in an airport security line. But here she was in April, standing near the front of a long TSA line, with a bag screener shouting that all passengers would need to remove their food items and place them in a separate bin.

She started rifling through her carry-on to find the candy bar and the plastic bag of trail mix that she knew were floating around inside. Other travelers, also visibly bewildered, started scrounging around in their bags for errant packs of Goldfish and squashed energy bars. The line, Gaul said, was moving noticeably slower than normal.

"It definitely caused a delay — not huge, but at least by like five or 10 minutes," the Georgetown University Ph.D student said. "Mostly it was just bizarre and absurd."

According to England, the snack removal recommendation is part of an effort to better detect explosives on planes, and to limit the number of bags that are flagged for special searches.

England said the concern is not that people may be hiding explosives or other illicit material inside of food. Rather, it's that the food itself can look similar to the components of an explosive — therefore making it more likely that bags with snacks would be flagged for a time-consuming manual search. Officials thought it might be more efficient, in some cases, to have passengers remove the snacks from their bags ahead of time.

"Some foods and some organic materials can bear a strong resemblance to explosive materials," he said.

England said he could not provide specific information on how a pack of pretzels could resemble an explosive. He disputed the idea that the new attention on snacks might be an excessive screening measure.

"There's a very good reason for everything we do. Nothing is arbitrary," England said.

He said there are no immediate plans to standardize the practice at every airport across the country, but the procedure is employed at times when supervisors think it might speed things up.

"It's not a requirement. It's a recommendation," England said. "But you might see them recommending a little louder during busy times of the day."

It remains unclear whether the snack removal protocol is effective in reducing wait times — whether the decrease in bags flagged for special screenings makes up for the disruption for passengers as they perform a last-second hunt for the food stuffed in their bags.

England acknowledged that there might be "isolated incidents" when asking passengers to remove food from their bags might slow things down, though he pointed out that, nationally, 96 percent of standard passengers have a wait that is 20 minutes or less.

Christina Saull, spokeswoman for the Metropolitan Washington Airports Authority, said that, so far, the new procedure has not led to longer wait times at either Reagan National or Dulles International airports.

That hasn't stopped the complaints on social media.

"Of all the TSA rules, the arbitrarily enforced 'dig every snack out of your bags' is the dumbest," tweeted Anne Keller, after she encountered the snack screening at National.

And passengers aren't just noticing in Washington. Travelers have complained about the practice being used at Dallas Love Field, Chicago O'Hare, Los Angeles International, Newark Liberty, and Hartsfield- Jackson Atlanta International. The recommendation is gaining traction at smaller airports, too — in Boise, Idaho; Greenville, South Carolina; and Manchester, New Hampshire.

"How bizarre," tweeted Cindy Armstrong at Redmond Municipal Airport in Oregon.

"Some terrorist is making bombs out of Frito-Lay," mused a passenger waiting at Orlando International Airport.

"It is a nationwide policy . . . making all parents stand in line longer with kids who have to pee," quipped a traveler who encountered the practice at San Jose International Airport.

"TSA asked me to take my snacks out of my bag and I feel personally victimized," tweeted Thea Neal of Kansas City, Missouri.

When Neal, a 29-year-old social media manager for a greeting-card company, was asked to remove her snacks, she immediately panicked. Had she missed a memo about new security protocol? And, more importantly, was TSA going to confiscate her food?

"I had a whole bunch of crazy snacks in my bag that I was really excited to eat," she recalled.

Happily, her snacks were returned after getting X-rayed in their separate bin. Still, she remains uncomfortable with the idea that this may become standard practice for every trip through airport security. The procedure doesn't make her feel safer — "It seemed, honestly, completely pointless," she said — and there are sanitary considerations to boot.

"I was lucky that everything I brought was prepackaged. But if it was fruit or something . . . " she said, shuddering to think about her food items rolling around in a plastic bin. "Those things are pretty disgusting. People put their shoes and their money in there."

Lauren Rosenberg, a 20-year-old college student from Houston, questions whether the practice will help the security lines proceed any faster. When it happened to her last Monday at Austin-Bergstrom International Airport, the process of hunting down the granola and Luna bars stuffed in her bag ended up holding up the line.

And Rosenberg started asking questions. Why did they need to look at her snacks? Was this a permanent new policy? The TSA agent in her line didn't know.

"I just need you to take out your snacks, your Doritos and your M&Ms," she recalled him saying.

Rosenberg said she worries that this is more than just another inconvenience foisted upon travelers. It's a slippery slope. Rosenberg, a college junior, is young enough that she hardly remembers a time when liquids larger than 3.4 ounces weren't banned from planes.

"The next thing they're going to make us take out of our bags is medicine," she said. "And that would be a real invasion of privacy."