But a survey of several popular city eateries — from swanky bistros to late-night diners — found shocking levels of trans fats in some dishes.

A Post reporter visited 12 restaurants in three boroughs and asked for a side of fries — only to discover that five contained the dangerous fat.

Just one of the guilty chow houses — Moonstruck Diner on West 23rd in Chelsea — ‘fessed up to having trans fat.

“We haven’t made the switch,” said an employee to a Post reporter posing as a customer.

Servers at the other four places said their food was trans fat-free — but the lab reports differ.

One worker at the Blue Water Grill in Union Square scoffed when asked if its fries contained the unhealthy fat, and insisted, “No, that’s illegal.”

But 2.2 grams of the heart-damaging oil was found in the hot spot’s 260.5-gram side of fries, according to a test conducted by Alliance Technologies in New Jersey.

Astoria Diner clocked in with the most trans fat in its side of fries, with 2.9 grams in one 317-gram serving, the lab results show.

. . .

Meanwhile, most of the eateries that failed the fat test disputed the findings.

Jimmy Polimenakos, whose family owns Uncle George’s, insisted that he used soybean oil that was labeled zero trans fat.

“Obviously I need to go to my supplier and trace the root of this,” he said.

The owner of the Astoria Diner also said he used trans fat-free oil.

“Impossible,” he said.

Chris Giarrapugo, the executive chef at B.R. Guest, the parent company of Blue Water Grill, vowed to conduct his own tests.

The spokeswoman assured that plans are still on track for a ribbon-cutting some time in the future, but would not say when.

Nor would she explain the repeated setbacks. “No reason,” she replied, when asked why the opening had been pushed back again. “This is all typical: We never confirm (an opening date) until we have a grand opening, which is still . . . slated. Just the date isn’t set in stone.”

In early January, construction screeched to a temporary halt after picketers hauled out a large inflatable rat at the site, located at 90-30 Metropolitan Ave., to protest the apparent use of non-unionized labor. But within weeks, progress had resumed; cranes were elevating the roof, while laborers replaced steel girders and erected brick walls at the front of the building.

Since then, however, progress has stalled again, according to civic leader Barbara Stuchinski — even as Michael’s Arts & Crafts, one of two retailers slated to share the old Heidelberg building with Trader Joe’s, appears closer than ever to opening. A Staples office supply store is also planned.

“I really don’t get it, because you see a sign for Michael’s, but the one store everyone wants to see, there’s no sign of,” said Stuchinski, president of the Forest Hills Community and Civic Association.

“When (The Shops at Atlas Park) was going up, it was boom-boom-bam, and the thing was opened in no time,” she added, referring to a nearby high-end mall. “But these construction guys just seem to be sitting around. When I tried to talk to them, they just shrugged and walked away.”

“Yellow M&Ms,” Mr. Cruz said in Spanish, and Mr. Ferrer directed him to a stack of yellow boxes, each containing 48 packages of peanut M&Ms. “That’s the one lots of people want,” Mr. Cruz explained. “I don’t have the money to get a lot of different kinds.”

Few sights are more familiar to New York subway riders than those teenage boys who peddle candy on the train, materializing just as the car lurches into motion and delivering a spiel about a basketball team or an after-school program. But behind every such vendor is a wholesaler like Delma’s, one of a handful of stores around the city that provide the teenagers with their stock in trade. Mr. Cruz now sells his candy on the street, but he was a subway vendor when he started buying candy at Delma’s, which has been in the business for about 15 years. He still encounters former subway competitors at the store. “I see a lot of people here,” he said.

But for the store’s employees, this clientele is a mixed blessing. “Those kids come in pairs, and they’re a pain,” Mr. Ferrer said. “Many times, they come to steal. You’ve got to watch them. One’s talking to you, and the other’s putting it all into his pants.”

. . .

There are certain constants in the subway candy-vending business. One is that the peanut M&M is the staple of subway candy. “Yellow M&Ms are No. 1,” Mr. Ferrer said. “I sell 10 boxes of yellow M&Ms before I can sell one of brown.”

Another is the use of a spiel, which can vary from the shopworn (“I’m selling for my basketball team”) to the ostentatiously candid (“I’m not selling for any basketball team”).

During his subway days, which lasted about a year and ended just recently, Mr. Cruz preferred a third variant: “I’d say, ‘I’m selling candy so I can get some money in my pocket. I’m not selling drugs or robbing anyone.'”

With car-less New Yorkers relying on rentals for weekend escapes in record numbers, demand for rental cars in Manhattan is expected to reach an all-time high this summer, industry insiders said.

That demand, coupled with a static supply of vehicles, is driving up the cost of renting a car. Prices are up more than 10% versus last summer and are expected to rise higher.

. . .

Industry experts say the cost of buying a new car for a rental company is about 40% higher than it was three years ago. The increased cost is creating a de facto cap on the number of available cars, and trickling down into the bills customers pay when they plunk down their credit cards at parking garages.

“Hot foods should be kept hot and cold foods should be kept cold. What is happening — for example, in a salad bar if food is not kept properly — could be contamination from an overgrowth of bacteria,” said Dr. Joseph Rahimian, attending physician at St. Vincent’s Hospital, Department of Infectious Diseases.

Health Department regulations mandate all cold foods, such as egg salad, be kept below 40 degrees.

That can be especially tough during the dog days of summer when daily temperatures soar.

“When a heat wave comes, like this week, my compressor works double,” said James Lee, executive chef at the Variety Café on West 48th Street.

“It usually turns on every half-hour, but when the temperature hits 90 degrees like this week, it turns on every 15 minutes. The energy bill goes up 25 percent during a heat wave to keep everything cool.”

. . .

According to Rahimian, bacteria can start growing within two hours for food not kept properly chilled — especially at large salad bars.

“I tend not to eat shellfish or sushi from these kinds of environments,” he said. “Cottage cheese and dairy products can go bad very easily in the summer months if it’s not the right temperature.”

Unpeeled fruits, which may not have been properly washed, are another risk, he added.

Very quickly, nasty food-borne pathogens such as bacillus cereus, campylobacter jejuni, E. coli and streptococcus can form.

Food poisoning, accompanied by bouts of diarrhea, nausea and vomiting, can strike immediately after contaminated food is ingested, but it can sometimes take longer. For instance, it can take anywhere from two to five days for symptoms of campylobacter infection, one of the most common causes of gastroenteritis, to strike.

Nationwide, there are about 76 million cases of food poisoning a year resulting in 325,000 hospitalizations and 5,000 deaths.