If Gina Traniello ever packs your bags at the grocery store, be ready to pay your bill, because you won’t be waiting long.

Traniello, 24, has mastered the art of bagging groceries quickly but properly, making sure the eggs don’t get crushed and that no full bag strains your biceps.

Sunday, the Tops Markets employee will test her skills against the best from grocery stores around the country at the National Grocers Association’s “Best Bagger Competition” in Las Vegas. The winner gets $10,000 and is expected to appear with David Letterman on his TV show.

If the contest sounds like a joke, Traniello at first thought it was. But she was persuaded to enter a store-level competition Tops held at the location where she works on Maple Road in Amherst near the Boulevard Mall. She won and advanced through Tops’ district competition, then won a statewide competition hosted by Price Chopper near Albany. She earned a spot in the national championship at the Mirage Hotel and Casino, against 22 other state champions.

Traniello is both nervous and excited about competing on a national stage. “I have made it this far, and going to Las Vegas is honestly the coolest thing ever, since I’ve never been there and there’s so much to do,” she said. “Just the experience will probably be the best part.”

Traniello was sent reusable fabric bags and a suggested list of grocery items to practice with at the store. In the national championship, contestants will be required to use only three reusable bags in the preliminary and final rounds. The entrants with the five highest scores will advance to the final round. In addition to the big first prize, there is prize money for runner-up spots.

What would Traniello do with a $10,000 first prize? “I would maybe go on a little shopping spree, but it’s basically more for school [expenses],” she said.

The contestants will be judged on speed, proper bag-building technique and distribution of weight between bags, as well as the entrants’ style, attitude and appearance.

Traniello, a Falconer native, lives in North Buffalo and is studying for her master’s degree in literacy at Medaille College, after earning her undergraduate degree in education. She has worked at Tops for 6½ years, transferring in 2009 to the store where she now works. Her job at Tops involves a variety of tasks, like helping customers and cashiers, and at times, bagging groceries.

Brian Smigiera, the store manager, called her “an excellent employee, very versatile in the store, great with customer service, a jack of all trades.”

Traniello describes herself as competitive, She has done some research, including watching a video of last year’s champion in action, to help her prepare. But she has a good sense of what she has to do.

“You clearly can’t have all the cans in one [bag], and glass can’t touch glass,” she said. “You want a box in the bag, with your boxes on the side, and then you pack from the outside in, and then you have stuff on top, like the eggs and bread.”

The grocers association says the contest, which dates to 1987, promotes good customer service and recognizes the contributions that front-end personnel make in a store. While there has not been a national champ from New York, Tops can claim a past title: In 1998, an employee at a Finast store in Ohio won it all. Tops owned the Finast chain at the time.

The contest has also stirred excitement at the Amherst store. A banner hanging near the entrance salutes Traniello’s statewide title, and her co-workers are rooting her on as she prepares for the finals.

“She’s taking it very, very seriously,” Smigiera said. “She’s intent on winning this.”