This paper addresses how food systems and transboundary food supply chains are mediated and shaped by (cross-) cultural and geopolitical borders that function as selective filters. We focus on the ways in which the political boundary in a formerly cohesive foodshed generates "edge effects" that affect (1) food safety, and (2) food waste, particularly in desert communities adjacent to the U.S.-Mexico border. We hypothesize that as these various boundary lines get "out of register" with one another, their dissonance creates both unexpected impacts as well as opportunities for positive change. This initial analysis demonstrates how multiple (and often permeable) social, economic, and ecological edges intersect with food supply chain vulnerabilities and economic opportunities at the border. Drawing on examples from food safety and food waste surrounding the "Ambos Nogales" port of entry on the Arizona-Sonora border, we document the ways in which the border produces ecological and social edge effects that are dissonant with the official legal boundary.