Urgent Bulletins

Pet Food Recall

Last update: May 1, 2007

Various pet food manufacturers, including Menu Foods, Del Monte Pet Products, Hills Pet Nutrition, Nestlé Purina PetCare Company, Sunshine Mills, Inc., and Natural Balance Pet Foods, Inc, have recalled a variety of their products because of concerns about contamination of an imported wheat gluten ingredient and, more recently, imported rice protein concentrate, with melamine. Melamine is an industrial chemical used in plastics and fertilizer.

Current Status

Although still under investigation, it now appears that the combination of melamine and cyanuric acid has been linked to the unusual outbreak of acute renal failure in cats and dogs that have eaten the suspect products.

For more information, please see the Imaging section (below).

For an updated list of recalled products, see the US FDA website at:

• US FDA Pet Food Recall page

Imaging

Gross Contaminants - new -

The following shows wheat gluten contaminated with melamine (Figure 1) compared with normal wheat gluten (Figure 2).

Figure 1	Figure 2

Microscopy

The following shows crystals (agglomeration of melamine and cyanuric acid) formed in the lab in cat urine by the addition of melamine and cyanuric acid. The composition of these crystals matches those found in the urine of affected pets when compared by infrared spectroscopy (FTIR).

Melamine/cyanuric acid crystals produced in vitro

The following images are of crystals in the urine of a cat suspected to be affected by the toxin.

Low Power	400x
1000x	SEM

Spectrography

The following images are FTIR (Fourier transform infrared) spectra of spherical yellow urinary crystals from three different cats, demonstrating homology (Figure 1). The crystals do not match common urinary crystals such as ammonium urate (Figure 2) or xanthine (Figure 3). Mass spectrometry has shown that these crystals contain ~30% melamine.

New in vitro testing has produced melamine/cyanuric acid crystals that match the unknown crystals (Figure 4).

Figure 1	Figure 2
Figure 3	Figure 4
Legend: Figure 1: Unknown crystal spectra showing homology across 3 individuals Figure 2: Ammonium urate (black) vs. unknown crystal (red) Figure 3: Xanthine (black) vs. unknown crystal (red) Figure 4: in vitro melamine/cyanuric acid crystals (red) vs. unknown crystals (blue)* Click on any spectra for full-size view [pdf]

* FTIR spectrum of crystals formed in the lab in cat urine (red) by adding melamine and cyanuric acid overlaid with a spectrum from yellow, spherical crystals found in urine from an affected cat (blue).