Angry in the Great White North

See all the posts related to the pet food recall.

In my first post on this story, I was confused as to how a rat poison could have gotten on the Chinese wheat in concentrations that would harm animals in North America:

The suspicion is that the poison was on wheat gluten imported by China, but that is more rumour than anything else.

It might be that aminopterin was being used as rat poison in traps used where the wheat product was stored and got into the food supply.

Here's my problem. If poison got into the bulk gluten supply, wouldn't it have been diluted to well below lethal concentrations during the processing of all that gluten into the final product? Unless the contamination was very severe, but then it would have been detected.

See, I assumed that aminopterin would have been used in rat traps. Even if the contents of one or two rat traps somehow got mixed up in the bulk wheat gluten, I would find it hard to believe that after all the mixing and processing, the aminopterin would have any effect, especially a lethal one.

Then I started to read how some people suspected that the wheat was sprayed with aminopterin.

I've been mulling that over, and then I read this from WBBM News in Chicago:

The federal Food and Drug Administration has said the investigation into the pet deaths was focused on wheat gluten in the food. The gluten itself would not cause kidney failure, but it could have been contaminated, the FDA said.

Paul Henderson, chief executive of Menu Foods, confirmed Friday that the wheat gluten was purchased from China.

Bob Rosenberg, senior vice president of government affairs for the National Pest Management Association, said it would be unusual for the wheat to be tainted.

"It would make no sense to spray a crop itself with rodenticide," Rosenberg said, adding that grain shippers typically put bait stations around the perimeter of their storage facilities.

Rosenberg is right. But it does then beg the question of how the aminopterin got into the wheat gluten (if indeed that is the source) at such high concentrations as to be lethal at the end of the production chain:

Aminopterin is highly toxic in high doses. It inhibits the growth of malignant cells and suppresses the immune system. In dogs and cats, the amount of aminopterin found -- 40 parts per million -- can cause kidney failure, according to Bruce Akey, director of Cornell's diagnostic center.

"It's there in substantial amounts," Akey said.

Donald Smith, dean of Cornell's veterinary school, said he expected the number of pet deaths to increase. "Based on what we've heard the last couple days, 16 is a low number," Smith said.

Aminopterin is no longer marketed as a cancer drug, but is still used in research, said Andre Rosowsky, a chemist with the Dana Farber Cancer Institute in Boston.

Rosowsky speculated that the substance would not show up in pet food "unless somebody put it there."

Some people are still resisting the idea that this was deliberate:

Henderson said Menu Foods does not believe the food was tampered with because the recalled food came from two different plants, one in Kansas, one in New Jersey. Menu continues to produce food at the two plants.

The recalled food came from two plants. It isn't clear that the poisoned food originated from both plants. In fact, this act seems to have been prompted by uncertainty over which plant was responsible:

Rat poison was found in pet food blamed for the deaths of at least 16 cats and dogs, but scientists said Friday they still don't know how it got there and predicted more animal deaths would be linked to it. After the announcement, the company that produced the food expanded its recall to include all 95 brands of the "cuts and gravy" style food, regardless of when they were produced.

If the source was the gluten, and the shipment was split between the two plants, then it makes sense. But this does not seem to have been established yet.

In any case, nothing I've heard makes me discount the theory that this was a deliberate act.