Ingredient file // Other
Fermented Raw Whey
A raw dairy starter culture, not a safety step
Fermented raw whey is unpasteurized cheese whey, soured by lactic acid bacteria and mixed into frozen raw dog food. It adds a little acid and some live bacteria, almost no nutrition, and no study shows it makes raw food safe.
- What it is
- The liquid left over from cheese making, kept unpasteurized and soured by lactic acid bacteria.
- Made from
- Unpasteurized whey from cheese making
- Main job
- Culture starter and acidifier
- Typical amount
- Not published; listed among the minor ingredients
- Watch for
- Unpasteurized dairy can carry pathogens and H5N1
- Not the same as
- Whey protein concentrate
Our read // In our catalog
In 1 of every 341 foods we track
Share of foods that list it
0%
9 of the 3,068 foods with an ingredient list on file, from 1 brand. 5 dog food topper, 4 frozen dog food.
Each square is 1% of the catalog
Where it sits on the label
Median position 6. In the top five of 2 foods, so it is usually a supporting ingredient.
Above the salt
Almost always listed before the salt, so there is more of it than a pinch.
Price per lb
Median of the cheapest bag price across 2 priced foods, 237% above the catalog. The price is the food's, not the ingredient's.
Who leans on it
100%
of the foods that list it are from Answers Pet Food. 1 brand use it in total.
What it is
How it is made
Whey is the liquid that drains off when milk becomes cheese, after most of the fat and casein stay in the curd. Raw food makers use it unpasteurized and let bacteria sour it.1,2,3
- 01 // Source Milk for cheese Milk goes into a cheese make. Most of its fat and casein end up in the curd.
- 02 // Process Curd drained The liquid that drains off is whey, about 93% water carrying lactose, some protein and minerals.
- 03 // Process Soured Lactic acid bacteria turn lactose into lactic acid. The pH drops, so acid whey keeps longer than fresh.
- 04 // Output Fermented raw whey A sour, unpasteurized liquid mixed into frozen raw recipes with no heat step to kill germs.
What is in it
Composition, dry matter
93
% water
Liquid whey as fed, per USDA. What is left is mostly milk sugar, so the whey in a raw patty adds acid and bacteria, not nutrition.
Why it is in the bag
What the manufacturer gets
-
01
Seeds acid-making bacteria
Soured whey carries lactic acid bacteria and lactic acid. In beef sausage, the version made with acid whey instead of curing salt had a pH 0.12 units lower and 0.66 log more lactic acid bacteria.5
-
02
The fermentation story
Raw brands present fermentation as the source of lactic acid that controls harmful bacteria, and as the probiotic in every bag. Whey is one of the cultured dairy ingredients carrying that message.11
-
03
A dairy leftover
Whey is a by-product left over from cheese making, not something produced for pet food. The fresh liquid spoils quickly, and souring it stabilizes it.1
How much No maker publishes the amount. On one raw pork label, whey sits after cod liver and before butter, kefir and salt, among the minor ingredients.12
Our read // The claims
What the evidence supports
Strong: controlled studies in dogs agree. Some: small or mixed dog data. Thin: mechanism or lab work only. None: nothing, or the evidence points the other way.
-
Owners say
Dairy is a common allergen for dogs
Evidence
- Strong
- Some
- Thin
- None
A critical review of diet trials that removed foods and then fed them again ranked dairy among the 4 most likely triggers, with beef, chicken and wheat. Whey carries milk proteins, though a small splash carries few.10
-
Critics say
Raw dairy puts dogs and owners at risk
Evidence
- Strong
- Some
- Thin
- None
FDA found Listeria in 32 of 196 raw pet food samples, and it now requires makers using unpasteurized milk to plan for H5N1. The risk belongs to the whole raw food, not to whey alone.6,8
-
Brands say
Fermentation keeps raw food free of pathogens
Outruns the evidence
Evidence
- Strong
- Some
- Thin
- None
In the lab, whey fermented with 10% kefir grains stopped added E. coli and Staph within 24 hours. No study has tested it in raw dog food, and FDA found Salmonella or Listeria in 4 samples from a fermented raw brand.3,7,11
-
Brands say
Adds probiotics that support gut health
Outruns the evidence
Evidence
- Strong
- Some
- Thin
- None
A review of 17 dog trials found purpose-made probiotics had a very limited, possibly unimportant effect on acute gut disease. No one has counted or tested the bacteria fermented whey adds to a raw patty.9,11
-
Brands say
Fermenting makes dairy easier to digest
Outruns the evidence
Evidence
- Strong
- Some
- Thin
- None
In a lab study of whey fermented with kefir grains, lactose was the one component that changed significantly. How much stays in a raw food is unpublished, and no dog study has tested tolerance.4
Straight answers
What owners ask
-
Q01
Is it just filler?
No, a starterIt is too small and too watery to add calories or protein worth counting. Its job is to bring acid-making bacteria into the mix. Whether that does anything useful in a frozen patty is unproven.1,2
-
Q02
Is it a protein source?
NoLiquid whey holds 0.76 to 0.85 g of protein per 100 g, according to USDA. Whey protein powders are a different, concentrated product. This is the thin leftover liquid.2
-
Q03
Does fermentation replace a kill step?
Not provenIn one lab test, kefir-fermented whey stopped added E. coli and Staph within 24 hours. But FDA names pasteurizing, cooking or canning as the steps that kill H5N1, and fermentation is not on that list.3,6
Who uses it
Brands, best sellers and the company it keeps
Top brands, by foods that list it
Usually listed with, share of the foods that list it
- Salt 56%
- Turkey 22%
- Pork 22%
- Pork Liver 22%
- Pork Heart 22%
- Pork Kidney 22%
- Pork Bone 22%
- Beef 22%
- Beef Liver 22%
- Beef Heart 22%
- Beef Kidney 22%
- Beef Bone 22%
On the shelf
Foods that list it
9 foods in our reviews list it. Here are some of them.
Show 7 more
Answers Pet Food Detailed Mighty Raw Chicken Frozen Dog Food40.6% proteinAnswers Pet Food Detailed Mighty Raw Turkey Frozen Dog Food40.6% proteinAnswers Pet Food Straight Simply Protein Pork Formula Grain-Free Dog Food Topper46.9% proteinAnswers Pet Food Detailed Mighty Raw Beef Frozen Dog Food40.6% proteinAnswers Pet Food Straight Simply Protein Beef Formula Grain-Free Dog Food Topper46.9% proteinAnswers Pet Food Straight Simply Protein Turkey Grain-Free Dog Food Topper46.9% proteinAnswers Pet Food Detailed Mighty Raw Pork Frozen Dog Food40.6% proteinOur read // On the bag
Judge the raw food, not the whey
Fermented raw whey sits near the end of raw and frozen labels, behind the meat, organs and bone, and it changes little about the nutrition. What it signals is an unpasteurized food. Ask the maker which pathogen kill step it uses, and handle the food like raw meat.
Sources
What we read
Checked October 1, 2026.
- 1 Whey
- 2 FoodData Central SR Legacy: Whey, acid, fluid (170885) and Whey, sweet, fluid (171282)
- 3 Nutritional Characteristics and Antimicrobial Potential of Goat Whey Fermented with Kefir Grains
- 4 Changes of Nutritional Characteristics of Whey Fermented with Kefir Grains - A Preliminary Results
- 5 Addition of acid whey improves organic dry-fermented sausage without nitrite production and its nutritional value
- 6 Cat and Dog Food Manufacturers Required to Consider H5N1 in Food Safety Plans
- 7 FDA Advisory: Do Not Feed Certain Answers Pet Food for Dogs Due to Salmonella and Listeria monocytogenes
- 8 Get the Facts! Raw Pet Food Diets can be Dangerous to You and Your Pet
- 9 Clinical effect of probiotics in prevention or treatment of gastrointestinal disease in dogs: A systematic review
- 10 Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats
- 11 Answers Dog Food Reviews
- 12 Answers Detailed Raw Pork 4lbs