MEXICO CITY — Tacos filled with pork, sizzling gorditas, juicy carnitas covered with salsa and gobbled down at sidewalk carts while pedestrians brush past — this is Mexico's version of a fast-food joint, but it is now in peril because of the swine flu epidemic.

With Mexico City authorities urging residents to dine at home to prevent the spread of the deadly virus, vendors at the tens of thousands of taco carts that line the streets of this overcrowded capital have seen business plunge. It hasn't helped that many people mistakenly believe you can contract the flu by eating pork.

Another blow came late yesterday when the city government ordered the streetside stalls to close for at least a week.

"What are we going to do to survive? The government is closing everything," taco-maker Jose Antonio Morales, 52, said today.

Even before the shut-down order, the epidemic was taking a major toll on business.

On Monday, on traffic-clogged Fray Servando street, 40-year-old Cristina Ramirez sat beside a sizzling plate of oil and a stack of tortillas in her stand offering quesadillas and gorditas — small, thick tortillas stuffed with meat and cooked in a skillet.

Of the seven food stands on her block, five were closed. She had just one customer.

"Everybody's afraid of other people. They want to eat alone," Ramirez muttered.

Just off the Insurgentes station, Gilberto Gutierrez saw his business plunge by 80 percent in the wake of the swine flu scare. Customers normally eat perched on stools or standing right next to other diners, spooning red or green salsa and pico de gallo from communal open containers.

Doctors had recommended against eating at the stalls during the outbreak, saying that eating in close proximity with others in possibly unhygienic conditions is risky. It is best to eat at home these days, said Dr. Samuel Rosete Jr., an ear, nose and throat specialist.

"All large gatherings where people could be coughing are bad," he said.

Person-to-person transmission of the swine flu virus comes through coughing or sneezing, or by people being in contact with viruses then touching their mouth or nose.

Mexico City historian Armando Ruiz Aguilar calls the tortillas, tacos, tortas, tamales and tlacoyos his people's Vitamin T. But the street cuisine has lost much of its allure amid a flu outbreak suspected of killing more than 150 people and sickening another 2,498 across Mexico.

"Noooo!" said 25-year-old waitress Iliana Molina when asked if she would eat at a street stand. "All those people with masks around you, coughing and rubbing against you? It's unhygienic."

The city will reassess on May 5 whether to keep the curbside stands closed, and might send health officials to check them, Mexico City's media office said.

The U.S. Centers for Disease Control and Prevention says swine flu viruses are not transmitted by food and eating properly handled and cooked pork is safe.

In the upper-middle class Condesa neighborhood, Luis Barajas, 50, would normally be busy slicing hunks from a big leg of pork to make tortas of pierna or cochinita pibil, a dish with slow-roasted, marinated pork.

"People ask me if it is OK to eat pork and I say 'of course,"' Barajas said. "But some people still avoid it because they associate it with the swine flu."

These are tough times for the humble taco stands, but Ruiz Aguilar believes they will survive.

"One can understand people being afraid of becoming sick after eating tacos in the current conditions," he said. "But I doubt this tradition could be lost in such a short time."