0.1 ppm is the limit for popcorn; the limit for oats and other grains is 30ppm, so 1ppm is well under the limit for oats. The 310 ppm mentioned in the article

0.1 ppm is the limit for popcorn; the limit for oats and other grains is 30ppm, so 1ppm is well under the limit for oats. The 310 ppm mentioned in the article is the limit for "grain aspiration fraction", which I believe is the stuff that falls off grain when you clean it with air(?), which is not something you'd normally be eating, so I don't know why the Guardian pulled that number out. The highest limit I saw in the EFCR tables for anything people would be eating seemed to be mint at 200ppm; most everything else was under 100ppm for human consumption, and the things with 200, 300, 400 ppm limits was animal feed.