In this space, over the weekend, I went off on quite a rant about importing stuff from China, in light of the massive pet food recalls. I later deleted it, because I thought it was mean spirited. But the question remains: why does the world’s bread basket need to import its wheat gluten? I know you’ve wondered too, and this article at Slate explains.

The U.S. Food and Drug Administration blocked imports of wheat gluten from a Chinese company on Monday. The agency identified the company as the source of the tainted wheat gluten that caused a massive pet-food recall last week. Given how much wheat is produced by American farmers, why do we need to import wheat gluten?

Because it’s cheaper than buying domestic gluten. We may be the world’s largest exporter of wheat, shipping a billion bushels to other countries in last year’s growing season. Yet we export relatively little wheat gluten. To extract the gluten from wheat, you have to separate it from the starch, by repeatedly washing and kneading wheat flour. But only four U.S. companies go through this process; last year, they produced roughly 100 million pounds of wheat gluten, about 20 percent of the domestic demand.