Raw Pet Food Safety: Minerals and Bacteria Risks

Raw Diet Pet Food Safety: New Research on Minerals and Bacteria

Feeding pets raw food has grown from a niche practice to a major trend, but two recent European studies provide concrete data on potential risks. Research from Germany reveals how commercial raw food processing can mask high levels of added inorganic phosphorus, while a Portuguese study quantifies the prevalence of dangerous, antibiotic-resistant bacteria in these diets.

Canning Masks Added Inorganic Phosphorus Levels

A team from Ludwig-Maximilians-Universität München in Germany investigated how processing affects phosphorus in pet food. Excessive intake of inorganic phosphate (Pi), sourced from additives like H3PO4, NaH2PO4, KH2PO4, and CaHPO4, can lead to adverse health effects in pets, including kidney disease and bone demineralization. In the European Union, declaring the use and amount of these additives is not regulated.

Lead researcher Sophie Löffelmann and her colleagues faced a problem: standard laboratory methods cannot differentiate between organic phosphate from meat and inorganic phosphate from supplements. They instead used a solubility method developed by Lineva et al., measuring phosphorus soluble in water after one minute (Psol1). This fraction is highly characteristic of added inorganic phosphate. The team prepared experimental cat diets, some kept raw and others canned, with controlled additions of inorganic phosphate.

Their results, published in the Journal of Animal Physiology and Animal Nutrition, showed a strong correlation between added Pi and Psol1 levels in raw samples. However, in the identical diets that underwent canning, the Psol1 fraction decreased significantly. “High amounts of Psol1 are found in commercial pet food,” the authors note. “The findings of this study indicate that the amount of added Pi in commercial pet food is probably even higher than can be expected by measuring Psol1.” Essentially, the canning process masks the detectable signature of these additives, potentially leading to an underestimation of their presence in the final product. For pets with conditions like kidney disease, where managing phosphorus intake is critical, this discrepancy is a major concern.

Raw Diets Harbor Resistant Bacteria at High Rates

Separate research from the University of Porto provides stark evidence of microbiological hazards. From September 2019 to January 2020, investigators collected 84 samples of commercial raw meat-based diets (RMBDs) in Portugal. They tested for clinically relevant pathogens that pose a risk to both pet and human health.

Mariana Ribeiro-Almeida, the study’s first author, and her team reported in Eurosurveillance that 69% of the samples contained multidrug-resistant bacteria. Specifically, 31% were contaminated with *Salmonella*, and 68.5% contained pathogenic *Escherichia coli* clones. Many of these *E. coli* strains carried the mcr gene, which provides resistance to colistin, an antibiotic of last resort for severe human infections. These bacteria are not neutralized by freezing and can spread in the home environment through pet bowls, saliva, and feces, creating a direct pathway for human exposure.

This study directly challenges the perception that commercial raw diets are produced under conditions that eliminate these pathogens. The high contamination rate indicates that safety standards for these products may be insufficient to protect household health.

The Dual Challenge for Pet Owners and Regulators

Together, these studies frame a dual challenge. The first is a regulatory blind spot. Without mandated disclosure of inorganic phosphate additives, pet owners cannot make informed choices, and the canning process further obscures the true mineral content. The second is a clear and present biological hazard. The Portuguese study confirms that raw diets are a significant reservoir for bacteria that can cause severe illness and resist treatment.

The phosphorus study has an important limitation: it used an experimental diet in a controlled setting. However, the researchers’ conclusion that commercial products likely contain even more added Pi than tests suggest is based on the solubility patterns they observed in widely available foods. For regulators, the implication is that current labeling and testing frameworks are inadequate for assessing the true nutritional profile and potential long-term health impacts of processed raw foods.

Making Informed Choices for Pet Health

For pet owners considering or currently using a raw diet, this research points to specific action steps. Discuss any dietary change, especially a raw diet, with a veterinarian. This is particularly important for pets with pre-existing health conditions.

If using a commercial raw diet, inquire about the company’s pathogen testing protocols and whether they disclose all mineral additives, including phosphorus sources. Assume all raw meat products pose a contamination risk. Practice stringent hygiene: handle food with separate utensils, wash bowls and surfaces with hot, soapy water immediately after feeding, and wash hands thoroughly. Keep raw food away from human food preparation areas and avoid letting pets lick faces immediately after eating.

Frequently Asked Questions

Isn’t freezing raw pet food enough to kill bacteria?

No. Freezing preserves bacteria; it does not kill them. Pathogens like *Salmonella* and *E. coli* survive freezing and become active again once the food is thawed, posing a continued risk of infection.

What’s the problem with added inorganic phosphate?

High levels of inorganic phosphate, commonly added to pet food as preservatives or mineral supplements, are linked to kidney stress, bone disease, and can accelerate the progression of chronic kidney disease, especially in cats.

Are homemade raw diets safer than commercial ones?

They present different risks. Commercial diets may have better mineral balance but still carry high bacterial contamination risks. Homemade diets are extremely difficult to formulate correctly and often lead to severe nutritional imbalances without expert guidance from a veterinary nutritionist.

Can cooking a raw diet at home solve these problems?

Gentle cooking at home can significantly reduce pathogenic bacteria, but it also alters the nutrient profile. Careful formulation and supplementation are still required to avoid deficiencies, and the issue of undisclosed mineral additives in pre-made mixes would remain.

Sources:
https://pubmed.ncbi.nlm.nih.gov/41456310/
https://pubmed.ncbi.nlm.nih.gov/38699902/
https://pubmed.ncbi.nlm.nih.gov/37003096/

Choosing a pet diet requires balancing perceived benefits with evidence-based risks. This new research adds substantial weight to the safety concerns surrounding raw feeding, highlighting specific chemical and biological hazards that demand careful consideration and rigorous hygiene from any pet owner taking this path.