Dog foodI don’t usually write about recalls of raw pet foods because… well, finding Salmonella, E. coli or Listeria in raw meat is far from surprising (although certainly concerning). However, the recent recall of Stella & Chewy’s products because of Listeria contamination is noteworthy.


Because their food is treated with high pressure pasteurization (HPP). This process uses high pressure to destroy bacteria. I typically consider HPP-treated food to be similar to commercial cooked products in terms of the risk of bacterial contamination and public health concerns. Yet, I add in the disclaimer that actual evidence of effectiveness on pet food seems to be limited. It makes sense that it would work; however, a variety of factors impact the effectiveness of HPP, so companies should have data that show their specific process works.

The big question here isn’t “why were bacteria in the food?” It’s a raw animal-based diet, bacteria are common contaminants.  The real question is “why were live bacteria in the food?” Figuring out how Listeria made it through the HPP processing is critically important. Hopefully there’s a real investigation into this.

There are a few possible explanations that I can come up with, and they vary greatly in the level of concern they would cause.

Post-treatment contamination: Careful review of the manufacturing process and testing (culture) of various environmental surfaces would typically be part of in investigation of this issue. If this was the problem, things such as physical or procedural changes and more QC testing might be indicated.

Ineffective HPP: There could be two different scenarios:

  • One is a breakdown in the process, with equipment problems, human error or some similar issue preventing an effective method from working. This is a problem but would presumably be fixable.
  • The other (more concerning) scenario is that the procedure they use is not actually adequately effective for the pet food they’re manufacturing.

Figuring out the cause of the problem is important to reduce the risk and help people make informed decisions about buying raw products.