Why We Lab Test Cat Food

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At Cats.com, we’re proud to be the only cat food review publisher that regularly submits cat food samples to an independent lab and shares in-depth reports on each food’s nutritional composition and any contaminants.

Lab testing costs a lot of money and takes a lot of time. So why don’t we just rely on the guaranteed analysis and information from the manufacturer?

Here’s why lab testing is so important.

We shouldn’t have to submit foods to a lab to get basic information about the nutrition and safety of our cats’ diets, but we do.

Lab testing is often the only way to know the real nutrient composition of a cat food.

The guaranteed analysis gives you a general picture of how much protein, fat, fiber, and moisture is in the food. But it’s far from perfect.

Most importantly, the guaranteed analysis is a set of minimum and maximum values. It tells you what the food is guaranteed to contain, not what it actually contains. That’s a big problem, especially when you’re trying to calculate the food’s carbohydrate content.

By sending the samples to a lab, we’re able to find out exactly how much of each key nutrient is in a particular recipe. Instead of believing that a food is at least 40% protein, we know that it’s 53% protein. Instead of estimating that it’s about 10% carbohydrates, we know that it’s 15% carbohydrate matter.

It might seem like a small discrepancy, but those numbers make a big difference to our cats.

Secondly, lab testing identifies potentially-harmful contaminants.

Our lab tests look for metals like mercury, aluminum, and lead. These are virtually never mentioned on the cat food label, but they can affect your cat’s health.

Bacteria, mold, and yeast can make your cat sick, and an elevated presence in our lab reports indicate that these contaminants made it past the manufacturer’s quality control system and, potentially, into your cat’s bowl.

Finally, we test for phosphorus and sodium, which almost never appear on the label.

Because these minerals can affect the wellbeing of senior cats and those with kidney disease, it’s important to know how much is in your cat’s food. Instead of chasing after this information from the manufacturer, we request these values in every lab report.

Reading the Report

A laboratory’s full pet food analysis looks a bit different from the guaranteed analysis you’re used to reading on the label, so let’s learn a bit about how to read and interpret these reports.

The pet food analysis report contains several columns that tell us about each analyte (that’s a term referring to each component for which the chemists tested).

Moving left to right, the columns tell us:

  • Which analyte we’re looking at in the row, e.g. “Yeast”
  • The result, which is the concentration of the analyte found in the sample
  • The minimum determining limit, which is how much of the analyte must be present before the test is able to measure and it with 99% confidence
  • The reporting limit, which is the smallest concentration of a substance that the lab can report
  • The units in which the reported result is measured, e.g. CFU per gram or milligrams per 100 grams
  • The date on which the analysis was completed
  • The method the laboratory used to complete the analysis, e.g. FDA-BAM, 8th ed, Ch 3 (click to see FDA documentation on this testing method)
  • Any qualifiers, e.g. problems or irregularities affecting the results

Interpreting the Report

Now we know what the report is telling us, but how do we interpret these data? Let’s walk through the various substances in each report and what the results mean.

Aerobic Plate Count, APC

As a generic test measuring the bacterial population of a food sample, the aerobic plate count (APC) is a rough indicator of the food’s safety. Lower values generally suggest that the food is sanitary and contains lower populations of potentially-pathogenic bacteria. For reference, values of 100,000 CFU/g are normal for fresh ground beef.

Yeast & Mold

This identifies the amount of yeast and mold in the food. High levels indicate potentially-harmful contamination.

Lead, Nickel, Zinc, Aluminum, Arsenic, & Mercury

These elements are sometimes found in cat food, primarily due to bioaccumulation in protein sources. Plant-based ingredients, including wheat, peas, barley, and corn, also accumulate toxic metals and metalloids from the soil in which they’re grown.


This toxic compound is sometimes seen in cat food, most likely due to the presence of ingredients with cyanogenic glycosides.


Ash is what would remain if all the organic compounds in the food were burned off, leaving behind only inorganic compounds (like calcium, magnesium, phosphorus, potassium, sodium, silicon, sulfur, and other trace minerals).

Lower-ash foods may be sought to help a cat with recurring urinary tract issues or kidney disease. Normal ash content in a cat food is between 5% and 8%.

Protein (crude)

This identifies the amount of protein in the food, not accounting for bioavailability. AAFCO guidelines require that cat foods meet a minimum of 30.0% protein content for growth and reproduction and 26.0% for adult maintenance. No upper limit has been established.

Total Carbohydrates

This identifies the amount of carbohydrate matter in the food. Carbohydrate matter is not nutritionally necessary for cats, and there is no minimum requirement for carbohydrates in cat food. At Cats.com, we recommend choosing a diet with less than 10% carbohydrates on a dry matter basis.

Fat (crude)

This identifies the fat content of the food, not accounting for bioavailability. AAFCO has established a minimum requirement of 9.0% fat for growth and reproduction and 9.0% for adult maintenance. It has not established a maximum fat limit for cat food.

Fiber (crude)

This identifies the amount of fiber (indigestible carbohydrate matter) in the food. AAFCO has not established minimum or maximum levels of fiber for cat food, but fiber content between 2% and 8% is normal.


This identifies the amount of moisture (water) in the cat food. The amount of water in the food varies depending on the processing method, and no minimum or maximum limit has been established by any authority.


This identifies the amount of phosphorus in the food. AAFCO has not established an upper limit for phosphorus in cat food, but the minimum is 0.5% dry matter weight for adult maintenance and 0.8% dry matter weight for growth and reproduction.


This identifies the amount of sodium in the food. AAFCO has established a minimum requirement of 0.2% sodium for growth and reproduction and 0.2% for adult maintenance.

AAFCO has not established a maximum upper limit, but the National Research Council (NRC) puts the safe upper limit of sodium in feline diets at 740 mg/mJ (megajoule) of metabolizable energy (ME), or 1.25 g/kg in 4000 kcal ME/kg diets). A controlled-sodium diet may be advisable for cats with kidney disease.

Recipe Name Brand Name Date Sampled
Acana Indoor Entree for Indoor Cats Chicken Turkey Acana Sep 20, 2021
Blue Buffalo Healthy Gourmet Kitten Chicken Entree Blue Buffalo Jul 22, 2022
Blue Buffalo Tastefuls Chicken Indoor Natural Adult Dry Cat Food Blue Buffalo Feb 15, 2023
Blue Buffalo Wilderness Chicken Recipe Grain-Free Dry Cat Food Blue Buffalo Feb 15, 2023
Blue Buffalo Wilderness Turkey Recipe Grain-Free Wet Cat Food Blue Buffalo Feb 15, 2023
Cat Person Chicken & Turkey Recipe Dry Cat Food Cat Person Nov 19, 2021
Cat Person Duck Recipe Shreds in Broth Cat Person Nov 19, 2021
Dr. Elsey’s cleanprotein Chicken Formula Grain-Free Dry Cat Food Dr. Elsey’s Dec 20, 2021
Dr. Marty Nature’s Feast Freeze-Dried Raw Cat Food Dr. Marty Apr 26, 2021
Feline Natural Chicken & Lamb Feast Wet Cat Food Feline Natural Feb 15, 2023
Feline Natural Chicken Grain-Free Freeze-Dried Cat Food Feline Natural Feb 15, 2023
Friskies Paté Mixed Grill Wet Cat Food Friskies Sep 20, 2021
Hill’s Science Diet Adult Chicken Recipe Dry Cat Food Hill’s Sep 20, 2021
Hound & Gatos Chicken & Chicken Liver Wet Cat Food Hound & Gatos Dec 20, 2021
Instinct by Nature’s Variety Grain-Free Limited Ingredient Turkey Recipe Dry Cat Food Instinct Dec 20, 2021
Instinct Original Grain Free Real Chicken Recipe Natural Wet Canned Cat Food Instinct Dec 20, 2021
Instinct Frozen Raw Bites Grain-Free Cage-Free Chicken Recipe Instinct Feb 15, 2023
Instinct Original Kitten Grain-Free Pate Real Chicken Recipe Natural Wet Canned Cat Food Instinct May 10, 2022
Instinct Original Grain-Free Pate Real Chicken Recipe Wet Cat Food Instinct Dec 20, 2021
Kirkland Signature Super Premium Maintenance Chicken & Rice Formula Cat Food Kirkland Dec 20, 2021
Made by Nacho Chicken Cuts in Gravy Recipe Made by Nacho Sep 20, 2021
Nom Nom Chicken Cuisine Nom Nom Nov 24, 2021
Northwest Naturals Freeze-Dried Turkey Cat Food Northwest Naturals Feb 15, 2023
Nulo Freestyle Cat & Kitten Turkey & Chicken Recipe Nulo May 10, 2022
Open Farm Chicken & Salmon Freeze Dried Raw Cat Food Open Farm Feb 15, 2023
Open Farm Harvest Chicken Rustic Blend Wet Cat Food Open Farm Sep 20, 2021
Open Farm Homestead Turkey & Chicken Dry Cat Food Open Farm Sep 20, 2021
Open Farm Surf & Turf Freeze Dried Raw Cat Food Open Farm Feb 15, 2023
Open Farm Wild-Caught Salmon Dry Cat Food Open Farm Sep 20, 2021
Orijen Original Cat Dry Cat Food Orijen Feb 15, 2023
Royal Canin Indoor Adult Chicken Recipe Dry Cat Food Royal Canin Sep 20, 2021
Simply Nourish Chicken and Brown Rice Kitten Food Simply Nourish Nov 11, 2021
Smalls Chicken Kibble Smalls Nov 18, 2021
Smalls Ground Bird Smalls Nov 18, 2021
Solid Gold Indigo Moon with Real Alaskan Pollock and Eggs Solid Gold Dec 20, 2021
Stella & Chewy’s Absolutely Rabbit Dinner Morsels Freeze-Dried Raw Cat Food Stella & Chewy’s Dec 20, 2021
Stella & Chewy’s Chick Chick Chicken Dinner Morsels Freeze-Dried Raw Cat Food Stella & Chewy’s Dec 20, 2021
Tiki Cat Born Carnivore Chicken & Herring Grain-Free Dry Cat Food Tiki Cat Dec 20, 2021
Tiki Cat Puka Puka Luau Chicken Wet Cat Food Tiki Cat Dec 20, 2021
Vital Essentials Freeze-Dried Chicken Dinner Patties Cat Food Vital Essentials Feb 15, 2023
Vital Essentials Freeze-Dried Chicken Mini Nibs Cat Food Vital Essentials Feb 15, 2023
Wellness CORE Natural Grain-Free Chicken Turkey & Chicken Liver Pate Canned Cat Food Wellness Dec 20, 2021
Wellness Kitten Plate Chicken Entree Wellness May 10, 2022
Weruva Cats in the Kitchen Chicken Frick ‘A Zee Chicken Recipe Au Jus Grain-Free Canned Cat Food Weruva Dec 20, 2021
Whiskas Purrfectly Chicken Wet Cat Food Whiskas Sep 20, 2021
Ziwi Peak New Zealand Venison Recipe Cat Food Ziwi Peak Dec 20, 2021
Ziwi Peak Air-Dried Mackerel & Lamb Cat Food Ziwi Peak Dec 20, 2021

We’re challenging the cat food industry to do better.

By going beyond the guaranteed analysis, publicizing the impurities found in cat food, and sharing information on components, like phosphorus and sodium, that seldom show up on the label, we hope to encourage brands to establish clearer standards and share this vital data with their customers.

For now, we’ll continue sharing this independent data and helping you to make better choices for your cat. Thank you for helping us make the world a better place for cats!

Disclaimer: Occasionally, we may supply lab reports and product chemical and ingredient analyses as part of a product or brand review. Such reports are provided by 3rd party analysis service providers and are intended for informational purposes only. Any liability arising from the accuracy and comprehensibility of such lab analyses will be under 3rd party service provider’s sole responsibility.
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About Mallory Crusta

Mallory is the Head of Content at Cats.com and an NAVC-certified Pet Nutrition Coach. Having produced and managed multimedia content across several pet-related domains, Mallory is dedicated to ensuring that the information on Cats.com is accurate, clear, and engaging. When she’s not reviewing pet products or editing content, Mallory enjoys skiing, hiking, and trying out new recipes in the kitchen. She has two cats, Wessie and Forest.

14 thoughts on “Why We Lab Test Cat Food”

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  1. Holle

    My cat will only eat Friskies. We fed them Wellness can and about 2020 she stopped eating it. Friskies was sold at Costco then so we bought it and they loved it. however, i’m now concerned about hyperthyroidism and seafood in general. so went back to Wellness… she won’t even eat the turkey salmon anymore. I never see reviews about Friskies… is it that bad that you don’t bother?

  2. Holle

    Thank you. I wish they didn’t make it taste so good! Because I really don’t want to use it but I’ve tried a few others and she just refuses to eat. Costco started selling a wet Pate and I was excited… but the one cat won’t eat it. This is recent so I don’t think you reviewed Kirkland canned pate yet. They also have a Tiki knockoff brand from Thailand now. I guess I could try it, same cost. I just like to stick with US made.

  3. Sue P

    I read your Wellness review on the canned Grain Free Chicken Entree pate and was surprised that you did not include Cassia gum, Guar gum and Xanthan gum in the list of “Ingredients we didn’t like”