I am the production manager at a small winery in Missouri. We send our wines for sulfite ppm testing at an independent laboratory. Using the lab's results, the government (TTB) allows us to state on our labels "Contains no detectable sulfites. These wines test at 0 (zero) ppm (not only less than 10 ppm but really zero ppm). The lab is Vinquiry, and their testing is accurate at less than 10 ppm.