Raw and Freeze-Dried Pet Food: Heavy Metals

The short answer

The research we reviewed doesn't point to raw food as a category. It points to game. In a 2023 UK study in Ambio, raw dog foods made with pheasant shot by hunters were the ones with high lead, while chicken-based products were not above the EU maximum. A 2025 study of raw dog foods sold in Hungary found lead above the permitted level in two of 33 dishes, and both contained game meat.

Freeze-dried food adds a second point. Freeze-drying takes the water out, so any metal left in the food reads higher per gram than it would in the same recipe with its water.

That gives you two questions to add for any raw or freeze-dried recipe: is there game in it, and how were the results reported?

What studies found in raw food

Our post on heavy metals in dog food covers the UK pheasant study in detail. In short, 77% of samples from three raw pheasant dog foods were above the EU maximum for lead in animal feed, while a processed food and chicken-based products were not.

The Hungarian study looked at something different. Its authors bought 33 preprepared raw dog foods, all frozen and labeled complete and balanced, from six makers on the Hungarian market. They tested minerals and heavy metals in each one. Lead turned up in seven of the foods, and two were above the maximum tolerable level the authors used. One was made with deer and roe deer. The other mixed deer, salmon and beef. All the other heavy metals they measured stayed below that level.

The same study raised a second issue that has nothing to do with metals. None of the 33 foods met every mineral recommendation the authors checked them against, and selenium was below the recommended minimum in all of them. So "labeled complete" and "tested complete" were not the same thing in that sample.

Both studies are about dog food, and both are small. The sources we reviewed did not include a large survey of raw pet food across many brands and meats.

Why game meat is the pattern

Game animals that are hunted are often shot with lead ammunition. When lead shot or a bullet hits an animal, pieces of it can stay in the meat.

The UK study's authors found that lead in raw pheasant dog food ran well above the lead in pheasant meat sold for people. They suggested a reason: mincing the meat for dog food may break the shot into smaller pieces that spread through the product.

That explains why the protein matters more than the word "raw." A raw chicken recipe and a raw pheasant recipe are both raw, but only one may contain meat from an animal that was shot. Farmed animals aren't hunted, so the ammunition question is about game. For the wider protein picture, including fish, see our post on fish vs poultry pet food.

Freeze-dried and dried foods

Freeze-drying removes water and leaves the rest of the food behind. If a recipe carried a trace of lead before drying, it still carries that lead after. It's packed into fewer grams.

That makes results hard to compare. A freeze-dried food tested "as fed" will usually show a higher number per kilogram than the same recipe tested wet, even though nothing was added. The fair way to compare is on the same basis, such as dry matter. Our guide on how to read pet food heavy metal test results explains dry matter and as-fed numbers.

The same water effect shows up in other studies. A 2021 Brazil study found that dry foods had higher concentrations of most of the toxic metals it measured than wet foods did. Our post on wet vs dry pet food covers that comparison.

Drying doesn't remove lead from game, either. In the UK study, a dried food made with pheasant was also above the EU maximum for lead.

The sources we reviewed did not include a peer-reviewed study that measured heavy metals in freeze-dried pet food as its own category.

Cats and raw food

Most of the research we found is on dog food made with game. The sources we reviewed did not include a study of heavy metals in raw cat food or freeze-dried cat food.

That doesn't mean cat products are different. It means the questions are the same. If a raw or freeze-dried cat food lists game, such as venison, pheasant, rabbit or other wild meat, ask how it was sourced. Our 5-minute cat food check walks through the questions to ask for any food your cat eats.

What to ask

Three questions cover most of what matters here:

1. Is any of the meat from game, and how was it hunted? Ask whether the animals were shot with lead or non-lead ammunition. Our dog food post covers this question for dog owners.
2. How are results reported? Ask for results per recipe, and whether they are as fed or on a dry matter basis. For freeze-dried food, that basis changes the number a lot.
3. What was tested? Ask whether the finished product was tested, or only the ingredients. Our post on how pet food is tested for heavy metals explains the difference.

Raw food has other concerns too, such as germs, which FDA covers in its guidance on raw pet food. This post covers heavy metals only.

FAQ

Does raw cat food have more heavy metals than cooked? The studies we reviewed don't show that. They point to game meat shot with lead, not raw food as a category, and both studies were of dog food. The sources we reviewed did not include a raw cat food study.

Why would freeze-dried food test higher? The water has been removed, so whatever metals are in the food are packed into fewer grams. Compare results on the same basis, such as dry matter.

Is game meat in pet food a problem? In the UK and Hungarian studies, raw dog foods with game had the high lead results. Ask whether the meat came from animals shot with lead or non-lead ammunition, and ask for results.

A note on your pet's health

This article is general information, not veterinary advice. Talk with your veterinarian before changing your pet's diet.

Raw and freeze-dried can be tested too

Raw and freeze-dried recipes can be tested like any other food. Heavy Metal Tested is a certification program that helps brands share independent results with owners. Learn how certification works.