According to the pet owner who sent in the food ExperTox found levels of 0.2 micrograms/gm. The owner claims that feeding his cat 5.5 ounce cans of cat food for 4-5 days (after that the cat didn't eat any additional), the cat had 90% kidney failure.

Math time: There are 155 gms/5.5ounces. Assuming 0.2 micrograms/gm/155 gms, the entire can would contain 31 micrograms. Let's assume it was 5 days of feeding. The cat would have consumed 0.155 mg total over 5 days. In looking at the cat pictures it seems an easy 10 lbs maybe 15 lb cat? Let's go with 10 lbs.

At a dose of 10 mg/kg a cat will show toxic effects from acetaminophen. A 10 lb cat is equivalent to 4.5kgs. Thus in order for a cat to start to show toxicity from a single dose it would have to consume approx 45 mg. A one time dose guaranteed to show toxicity is 50-100 mg, and a follow up dose within 24 hrs is usually fatal.

Cat toxicities

We have a little paradox here of the cat consuming a total of 0.155 mg over a period of 5 days, yet one would not expect to see toxicity occur until the cat has accumulated 45 mg. Now the queston becomes at the end of 5 days how much of the 0.155 mg was in the cat? A cat will clear 85% of the dose within 24 hrs. Ummm... time for yet more math: After 1 day the cat would have retained 4.65 micrograms. After day 2 we have 85% of the day two dose excreted plus 85% of the 4.65 micrograms or 5.35 micrograms at the end of days 2... and at the end of day 5 within minutes of the last feeding the highest concentration of acetaminophen would be 36.47 micrograms, or converting back to milligrams, the highest concentration obtained in the cat would be expected to be 0.0364 mg.

The highest dose the cat was exposed to in theory was approximately 0.0364 mg, and yet most studies show toxicity starting at 40 mg or 1011X the dose this cat was exposed to in vivo. The owner makes a big adoo on his site that these small amounts starting at 0.0310 mg increase over 5 days to 0.0364 mg was the cause of death for the cat.

The owner's conclusion was: Chuckles received at least a 30 microgram dose of acetaminophen, courtesy of the pet murdering criminals at Menu Foods, with each can of food until she became too sick to eat.

But it seems a stretch to conclude that an accumulative 1/1000th the lethal dose for 5 consecutive days would kill the cat.

Curiously the main toxicity of acetaminophen in a cat is liver damage. Yet this cat died of kidney failure. The owner also remarks about the findings that cyanuric acid (used in pools), and which can react with acetaminophen to produce carcinogenic compounds was a contributing factor. Given the very short period of time, that also seems a leap of faith. Cyanuric acid by itself is non-toxic.

As far as is known the cat in question could have died of some other poison than the consumption of acetaminophen, totally independent of the food consumed.