Of course, this meaning is not the intended one. In reality, this aisle is similar to one labeled "ethnic foods" at other groceries. There seems to be a distinction being made between foods that are "cultural" or "ethnic," and foods that are not (i.e. what is found in the other aisles).
What makes a food "cultural"? The other entries on the signs give some clues: not a definition but a series of examples. In the foreground the sign lists Mexican and Jewish foods; in the background at the other end of the aisle, Asian, Indian (distinct from Asian?), and Mediterranean.
What do these five examples have in common? With the possible exception of Mediterranean, these terms describe social groups that have faced marginalization and exclusion from U.S. society at some point in their histories. ("Mediterranean" seems to me more a trendy term for a certain health-conscious diet than a coherent social group or cuisine.)
- Is the answer that to be "cultural" is to be an immigrant? Perhaps, but think of how many emblematic American picnic foods have immigrant origins: hamburgers, hot dogs, coleslaw, French fries (actually Belgian), ketchup. Is a hamburger a "cultural food"? Not at this Whole Foods, it seems.
- Is the answer that to be "cultural" is to practice a religion other than Protestant Christianity? Perhaps, though it is striking that kosher food is listed on the sign but not halal food. Is Islam "not cultural enough"?
- Is the answer that to be "cultural" is to be nonwhite? Not in the case of Jews, of course. Some people of Indian descent identify themselves as white according to the U.S. Census racial classifications (which have a dubious past). Wouldn't African foods be advertised as part of this aisle if being nonwhite were essential to being "cultural"?
In short, there is no coherent principle that accounts for every example. But it is clear that the anthropological concept of culture is not guiding the designer of this store. An anthropologist would say that all social groups have a culture: learned behavior for coping with the environment, including foodways. Native-born white Protestants have a culture (or cultures) of food just as much as the groups singled out in these signs.