To make po-boys, someone has to know how to make the bread just right, with that essential crackle in the crust and air through the crumb. Someone has to have a good, hearty roast beef recipe and no fear of pouring on too much gravy. Someone has to have access to fat, salty Gulf oysters, someone has to pack a sufficiently peppery sausage and someone has to make a thin hot sauce with plenty of tang. Because all of that is local, all of that was imperiled by the Katrina disaster, from the baker to the hot-sauce maker to the recipes running through family lines and the fishermen working local waterways. They're back, to some extent and in some form or another. But the other essential ingredient to New Orleans' quintessential comfort food is the customer with a local palate, the customer who will disregard multimillion-dollar advertising campaigns, ignore colorful coupons and walk past a rogue's gallery of national fast-food chains to get to a respectable po-boy shop at lunchtime.

A call to arms " or, at the very least, a call to lunch " is taking shape for those who prize the po-boy. This Sunday marks the debut of the New Orleans Po-Boy Preservation Festival, a block party on Oak Street that simultaneously seeks to showcase the great variety and craft of po-boy making around the area and also raise awareness of the sandwich as a local cultural expression, something valuable but also vulnerable.

'The po-boy is so New Orleans. Our concern is that, with the Subways and Quiznoses out there, we don't want kids growing up not knowing what po-boys are," says Jim Elliot, a school counselor who is helping organize the festival through the Oak Street Association.

Just about everyone involved with the event seems to share a sense of wonder that there isn't already a po-boy celebration somewhere on the city's festival calendar. But the idea that po-boys should be venerated and are even in need of preservation, as the festival's name implies, is a fairly recent development.

The impetus is the increased competition from national sandwich shop chains, says Sandy Whann, president of Leidenheimer Baking Co., a Central City company that dates back to 1896 and today produces much of the city's daily supply of po-boy loaves.

'For a long time (the chains) seemed to ignore the New Orleans market because we had such a strong local sandwich tradition with the po-boy, but that has really changed," says Whann.

In 2004, Whann and a group of other po-boy suppliers and purveyors formed the Po-Boy Preservation Society. The idea was to start a marketing collaborative for the po-boy business, something akin to the dairy industry's national 'Got Milk?" campaign. Bumper stickers were distributed and the idea of a po-boy festival was hatched. Katrina put the society in hiatus and its proposals " including an exhibit for the Louisiana Children's Museum " are in mothballs. But the idea of a festival still proved magnetic.

Earlier this year, the Idea Village, a local nonprofit business incubator, took up the project as something with the potential to help businesses across a wide geographic and demographic spectrum of the city. The local association of merchants and residents has been promoting the historic shopping corridor as a revitalized hub for locally owned businesses. Elliot says po-boys seemed like a great vehicle to showcase why such local enterprise is so important.

'Po-boy shops get to that neighborhood feeling we have in this city," he says. 'If those places go, we start looking more like Anywhere USA."

The po-boy is an argument for local culture and the local economy that people can easily relate to, he says, and a festival built around it also seems like a compelling lure to get a crowd out to Oak Street. There will be two music stages with popular local acts like the Iguanas and Walter 'Wolfman" Washington, a beer garden, arts and crafts booths and children's activities. Representatives from the Martin and Gendusa families " widely credited with creating the po-boy and baking the first po-boy loaves, respectively " will be on hand for a commemoration. Most of all, though, there will be po-boys.

Fifteen local restaurants had signed up as vendors at this writing. They represent an honor roll of the city's great po-boy purveyors and also show the diversity of local practitioners. Elliot has been encouraging them to sell small slices of their sandwiches so attendees can sample many throughout the afternoon. Judges will award prizes for such categories as best roast beef and best traditional seafood, while attendees can vote on a 'people's choice" winner. Given the intense subjectivity of local po-boy preferences, this should prove an interesting exercise in participatory democracy.

'People get into points like toasted versus not toasted, buttered or dressed. You talk to someone from New Orleans about po-boys, well, do you have three hours?" says Elliot. 'Now, I like Parkway's roast beef a lot, but then there's Parasol's and Domilise's, too. I like the oyster po-boy at Ye Old College Inn and I like the shrimp and oyster mix at Mandina's. I like Liuzza's, too. Thank God we still have this many though, is the thing. Thank God it's not just chains all over the place."