To this day, China has yet to fully lift its ban.

And yet faced with a massive, and apparently intentional contamination of imported Chinese wheat, corn and rice gluten -- an "economic adulteration" that has already poisoned thousands of dogs, cats, pigs, chickens and probably humans -- the U.S. Food and Drug Administration stubbornly continues to allow the import and sale of suspect Chinese gluten and protein concentrates.

We have no idea exactly how toxic melamine is in humans, or whether it was the only industrial chemical used to spike nitrogen levels, or for how long and on how many imported Chinese products this dangerous fraud has been perpetrated. What we do know is that melamine is an impurity that should absolutely not be in our pet, livestock and human food supply -- and yet, there it is. It is killing our cats and dogs, contaminating our livestock, threatening the public health, and potentially costing American producers and retailers hundreds of millions of dollars in recalls and lost sales. What we know is that this poison has been introduced into our food supply via three different products imported from three different Chinese manufacturers, that the practice is widespread, and that it continued even after the news of the first melamine-tainted wheat gluten broke worldwide.

Given what we know, there can be only one response: it is time to ban the import of all Chinese gluten and protein concentrates.

If China could impose a four-year (and counting) ban on imported U.S. beef due to a single sick cow, then the U.S. is certainly more than justified to ban imported Chinese gluten and protein concentrates in light of the evidence already known. This is a product tampering case of massive proportions, and only an import ban on suspect Chinese products can start to restore public faith in the safety of our food supply.

It is also the only legal and economic tool available to force the Chinese government to fulfill its obligation to assure the safety and purity of the billions of dollars of agricultural and manufactured food products it exports annually to the U.S. and the rest of the world.

Despite the overwhelming evidence of widespread and intentional adulteration, the Chinese government has refused to accept responsibility, and refused to let FDA officials into the country to inspect the manufacturing facilities in question. This is simply unacceptable, and only a broad and immediate ban can send a strong enough message to the Chinese government that their total and complete cooperation is absolutely required if they are to retain the U.S. as an open market. Only a costly ban can incentivize China's honest brokers and producers to pressure their own government to crack down on those cheaters who are undermining the integrity of their industry.

It is time for the FDA to stop dithering and prevaricating, to stop protecting the identity of distributors and manufacturers at the expense of consumers, and to stop focusing on allaying public fears even as the known risk to public health steadily expands. It is time for the FDA to stop promising costly border inspections it simply does not have the resources to thoroughly carry out.

It is time to impose a ban on Chinese imports.