So we have covered why you can trust your vet to give you diet advice, and the brief history of pet foods. Today we will talk about how it is made and answer the question: What is pet food made from? I have included the most popular and trendy ingredients and supplements found in pet foods today.

So, what is pet food made from?

Due to the length of this post, I have focused mostly on primary ingredients. There are many nutrients, vitamins, fats and preservatives that are commonly used in pet foods that I have not mentioned.

The process of making pet foods has not changed very much in the last 50 years.

Even though there are more varieties of pet foods on the market than ever before, the process for making pet foods is essentially the same today as it was for our grandparents pets.

Quick Guide- Follow these links to jump to a section!

Types of Pet Food:

Kibble

Canned

Frozen raw

Fresh raw

Freeze dried

Ingredients:

Meat

Animal by products

Eggs

Wheat

Oats, barley, rice

Corn

Soybeans

Exotic grains

Dried beans, peas, lentils and chickpeas

Potatoes

Beet pulp

Cranberries, blueberries and other fruits and vegetables

Glucosamine, chondroitin and other supplements

 

Types of pet foods

Kibble

Probably the most popular form of pet food for both dogs and cats, kibble-type food are a dry food made of dried meat and/or by products ground to a meal, with carbohydrates and fats added to hold everything together and balance the nutritional profile.

Let me say this: ALL products used in a kibble diet have been dried and ground to a meal first, similar to flour in texture. There is no other way to make the food.

The base ingredients, along with additional vitamins and supplements, are mixed together and heated. Water is added to the powdered carbohydrate, which is then mixed into the meal mixture along with liquid fats. The mixture is then heated and pushed through and extruder, cut into shape and heated further to “puff” the texture of the kibble. This is then heated and dried until it is down to 6-10% in moisture content.

The kibble is then cooled and sealed into bags for storage and transport.

All kibble formulations have a carbohydrate component. In “grain free” diets this may be potato or sweet potato. The carbohydrate is necessary to the texture and shape of the food. Unfortunately, there is no other way to make a kibble.

Canned/Pouched Foods

Canned-type foods (including pate, meat-in-gravy and pouch formulas) will usually start with a meat base, made from chunks or ground meat depending on the final texture desired. This can include meat from animal muscle, animal by products or a combination. The meat is mixed and heated, and then the additional carbohydrates, vitamins and supplements are added.

The final addition is the gravy component, which can be made from thickeners like wheat gluten or gelatins. The slurry is mixed and heated, and then formed into a loaf on a baking sheet and cooked to the proper temperature.

Once cooked, the loaf mix can be put directly into cans or cut into shapes for chunky or shred-style canned/pouched food. Meat-in-gravy styles will have an additional gravy added to the chunks/shreds in the cans or pouches. The cans are then sealed and sterilized.

If a food is intended to be vegetarian, textured vegetable protein (TVP) may be used as a meat substitute.

It is most commonly made from soybeans, but can be made with wheat gluten, oats or cotton seeds. TVP and other protein gels are a common ingredient in many meat-in-gravy products.

Canned foods generally have a 70-75% water content, and are usually much higher in protein than dry kibble (measured on a dry matter basis). Since the cans or pouches undergo sterilization, they also tend to have fewer preservatives.

They are also usually lower in calories per serving. When switching from a dry kibble to a canned food, you may have to feed more of the canned food to meet your pet’s energy needs.

Other types of pet food

Frozen raw/lightly cooked foods

These foods come frozen and are usually made with raw or lightly cooked ingredients. Most often they are sold in chubs, although some manufacturers make individual sealed portions. Companies will have different standards as to how the food is processed or tested to be sure it is safe from food pathogens. These type of foods are highly perishable and can not be stored for very long. They must be defrosted before use, stored properly and used quickly after opening.

Fresh raw/lightly cooked foods

These foods are similar to the frozen varieties, except they are sold in refrigerator sections of stores. Most of these foods will be vacuum sealed and then pasteurized. Just like the similar frozen diets, companies will have different standards for processing and testing for pathogens. These foods are also highly perishable, especially if stored incorrectly, and must be used quickly after opening.

Dehydrated/Freeze dried foods

These diets can be made from raw or cooked ingredients. They are usually made from meat that has been dried or frozen, and the freeze dried. This process reduces the water content to levels that should inhibit (but not prevent) microbial growth. Some companies also use high pressure pasteurization (HPP) to prevent any food pathogens, while others rely on testing. You will have to contact each company to find out their procedure. The appearance of freeze dried foods is similar to kibble diets. Most owners add water to the food before feeding.

Pet food ingredients, and how they are labeled.

Now it is time to move on to the more controversial part of this post. Ingredients! This is where things tend to get confusing for people when researching pet foods. What is pet food made from?

First, allow me to assure you that there is no such thing as an ingredient that is used as a “filler.” Every ingredient is in there for a reason. No company is going to add something to their pet food that has no purpose (even if the purpose is marketing, and not nutrition). These companies are not medieval bakers tossing sawdust into their loaves to stretch out the flour.

Some ingredients come in different forms, and/or have different grades associated with them (see Meat).

The only way to know what grade a particular company uses of these products is to contact them directly. You can usually assume that a cheap pet food is using a lower quality, less expensive grade for their foods. However, many mid level pet foods use the same quality ingredients as the ones labeled “super premium.”

There is no such thing as “human grade” pet foods. Or rather, almost no such thing.

A company that advertises it only uses “human grade” ingredients is being deceptive, because the words have no legal meaning. The term “human gade” is not applied to a product until it has completed the manufacture and packaging process. It doesn’t matter what the ingredient is, once it is designated for pet food it can no longer be called “human grade.” This term is pure advertising and has no bearing on the quality of the food.

The exception to this rule is a pet food product made from entirely human grade ingredients that is processed and packaged in a human manufacturing facility.

The term “made with human grade” ingredients simply means that something in the food was once listed as human grade. It will be no more than 3% of the final product. You have no idea which ingredient, how much of it was used etc. It does not tell you anything useful.

Pet food labels are deceptive and tricky.

Companies know that many people now read them and use them to determine the quality of the foods. These companies have adjusted how they list things, to make their food more desirable to the consumer. See my next post on pet food marketing.

Pet food labels contain a lot less information than we think they do. Many veterinary nutritionists advise that we spend less time looking at and comparing labels until changes are made to them (if this happens).

Meat

Most pet foods will contain animal flesh in one or several forms. The most common meats found in pet food are chicken, beef and pork. Lamb use to be more uncommon, but is now pretty standard.

There is a recent trend towards the use of more exotic (and usually expensive) proteins, like fish (salmon, whitefish, trout), rabbit, duck, or kangaroo. These meats are mostly raised abroad and imported in the the country. Historically, horse meat was used in pet food, but is no longer allowed in foods made or sold in the U.S.

The exact definition changes a bit depending on species, but the types of meat used in pet foods can include the animal muscle, heart, tongue, esophagus, and connective tissues and fat. It can not contain bones, however. Those are processed separately into bone meal or are added into animal by products.

For a kibble product, the meat has to be rendered (fats removed) and dried, and then ground into a meal before it is added to the food.

So any kibble product that lists “chicken” or “beef” as an ingredient, as opposed to “chicken meal” or “beef meal” is being deceptive.

Since ingredients are listed on a label by weight, you have no way to judge how much chicken or beef is really in the kibble when they are listed like this. All the “chicken” on the label tells you is that before it was dried and ground to a meal, the chicken weighed more than the next ingredient. It is deceptive because all a company has to do is use a small amount of the “meat” in order for it to be listed first.

As meat loses most of its weight when the water is removed, it is likely that if the company listed the meat as it was used in the food it would be much further down on the label.

This manipulation is done precisely so that owners who look at labels are deceived into thinking the food contains more meat, by weight, than is really in the food.

For canned foods you can expect the proteins to be labeled as “chicken” or “pork,” however, since they have not had to be made into a meal for processing.

Meat can also be listed by specific organ part, most usually as “chicken liver meal” or the like. Although liver (and similar organs) can be considered a by product of the meat production, this single organ origin is likely to be listed separately if the food contains no other by products. Liver is high in vitamin A, hence its inclusion in many pet foods.

Higher quality pet foods will usually list the meat meal by animal, saying something like “chicken meal, beef meal.” If the ingredient is listed simply as “meat meal,” “animal meal” or “fish meal,” then it is of an unknown composition, most likely of several kinds of animals. Companies will also use “poultry meal” for an unknown mix of chicken, turkey and other fowl. The use of generic animal meals is usually seen in the lower quality products.

There is no way to know, from looking at a label, what quality of meat or meal a pet food is made from. Not all “chickens” or “chicken meals” are the same, even if they are called the same thing on a label. You will have to contact the individual pet food manufacturer to ask about their products.

Meats and meat meals will vary in price based on the species origin and quality of the product.

Only roughly 40% of a slaughtered animal is meat protein that can be carved from the carcass, and much of this will be sold for human consumption. The rest of the meat will be removed from the carcass mechanically- this is the meat that usually ends up in pet foods or ground meat products like sausages/hot dogs.

So, for a steer weighing 1200 pounds at slaughter, the producer can expect about 500 pounds of boneless meat cuts.

The 60% of the remaining carcass will be processed as ground meat and by product, or for use in other industries (such as leather producers or cosmetics).

Beef, chicken, pork, eggs and fish are all proteins that are commonly associated with food allergies (although confirmed food allergies in pets are rare overall). I will cover this in another post in more detail.

ANY protein can trigger a food allergy. Food allergies are not related to the quality of the protein. Pets usually develop food allergies over time and with repeated exposure to the protein. It is best to limit the kinds of meat your pet is exposed to (stick to the common chicken, beef, pork and lamb products), and save the exotic proteins in case your pet does happen to develop one in the future.

Animal by products

Americans are strange, in that we like to eat meat but we tend to avoid everything but the animal muscle. Technically, the U.S.D.A considers everything except the muscle meat a by product of the animal manufacturing or slaughtering process.

This includes organs like the liver, kidneys, pancreas, thyroid, stomach, large and small intestines, lungs, brain and blood. It also includes inedible parts of the animal like feathers, hooves, fur, teeth, leather and bones.

So technically even things that Americans are willing to eat (sometimes) like marrow bones, sweetbreads, liver and tripe are by products. Sausage casings made from animal intestines are by products. Eggs and milk are also animal by products, since they are products produced from the animal manufacturing process.

See, it gets complicated further. Animal by products also include also include animals that are sick or diseased, and even some animals from zoos.

So what is your pet eating when the label indicates that there is a by product in it? It depends…

Animal by products used in animal feed can not contain inedible parts like fur, feathers, teeth or animal hide. It does include parts often eaten by humans like liver and kidneys but will also include things that humans usually don’t eat, like lungs and udders.

The by products are mixed, processed and rendered, and then either used as-is or made into a meal. There are different grades of by product as well by product meals. Higher grades have more and a higher quality protein, whereas lower grades will have a lower protein content and may be less digestible.

Animal by products can be identified by species origin, as in “chicken by products,” or they can be a generic mixture labeled “animal by products,” “meat by products” or “poultry by products.”

Even quality pet food manufacturers use by products in their food, although companies are moving away from the practice. The higher grades of by product are only slightly lower in protein than a primary meat and are generally quite digestible. The lower grades and mixed species grades are not as high in protein and digestibility.

Obviously, it is “natural” for dogs and cats to eat some by products.

If they were hunting animals, they would certainly eat them. And a high quality by product in a food is still better than a low quality primary meat (or meat meal). However, for many consumers the “ick” factor is too high to overcome, and they avoid products that contain them. Many companies are phasing out the use of by products due to consumer demand.

The hallmark of a low quality pet food is one where the primary meat protein source is an unidentified “animal by product” or “meat by product.”

Of course, animal by products are less expensive than their equivalent meat or meat meal.

Eggs

Eggs are used in pet foods as a binder and source of digestible proteins, along with fats and fatty acids. They are often found in foods designed for sensitive stomachs or for pets with certain food allergies. Eggs can be a food that some pets develop allergies to, however, as mentioned in the Meat section.

Wheat

Wheat’s presence in pet foods is a hot topic in discussions these days. However, it has been an ingredient of dog biscuits and kibble from the beginning. It was the most common source of carbohydrate in pet foods prior to the current “grain free” fad.

Wheat is classified as a grain. There are several forms of wheat that appear on pet food labels, and they serve different purposes. Wheat is added as a source of protein, carbohydrates, minerals, vitamins and fats.

Wheat can be listed as a whole grain, in which case it mixed in as a flour to bind the kibble and give it texture.

Whole wheat contains all of the constituent parts of the wheat kernel except the outer chaff. Wheat can also be used as its isolated parts as well.

Wheat gluten is very high in protein, since most of the carbohydrates have been washed away. It is used to increase protein content in the food, to thicken gravies and to make the “meat” chunks in canned foods.

Wheat bran is the outer hull of the wheat grain. Wheat bran is added to pet foods because it is high in fiber and certain fats. It also contains protein, carbohydrates, minerals and vitamins.

Wheat germ is the embryo of the wheat seed. It is high in many essential nutrients, vitamins and fats, and also contains fiber.

Wheat products are generally well tolerated in pet foods. While some owners feel that eating grains is unnatural for dogs and cats, the replacement for grains are other, simpler carbohydrate sources like potato and sweet potato (see below).

Due to its current and historic inclusion in pet foods, wheat is one of the proteins commonly associated with food allergies. Wheat allergies are considered rare. Beef, chicken, fish and eggs are far more common food allergies.

Oats, barley and rice

There are other grains that are often found in pet foods. Oats, barley and rice are all common ingredients. Depending on the grade and quality, they can add protein, carbohydrates, fiber, vitamins and fats to the diet. Also, these grains are considered highly digestible and better for your pet’s health than simple carbohydrate ingredients.

These ingredients can come in different grades, but are almost always going to be a grade of animal feed and not from the human food chain. Brewers rice, for instance, is simply rice that is small or broken into pieces, and as such unsuitable for resale as a human food.

The nutritional profile of these grains is going to vary depending on the source and the quality. You will have to contact the company for more information.

Corn

This is another controversial ingredient in pet foods. Corn and corn products are used in pet foods as a source of protein and carbohydrates, essential fatty acids and nutrients. Corn is highly digestible in its processed form and is considered a good source of protein and carbohydrates.

The corn that is in pet foods is not the sweet corn you buy and eat as corn on the cob. Instead it is a form of animal feed called dent corn. This corn is smaller than sweet corn, and has a different nutritional profile.

Corn can be used whole, as in cornmeal or corn flour, or used in parts to balance a pet food’s profile.

Cornmeal/corn flour– This is the entire kernel of corn dried and ground to a meal. It contains protein, carbohydrates, fiber, fatty acids and nutrients.

Corn gluten– This is processed corn where the carbohydrates have been removed and the protein concentrated. It is a highly digestible protein source. However, corn protein is missing certain essential amino acids, and so must be balanced by another source of protein that provides them.

Cornstarch– Use in pet foods as a highly digestible source of carbohydrates, it can also be added as a thickener to gravy-based pet foods. Cornstarch is the carbohydrate material  left over after processing the corn gluten.

Corn sugars– High fructose corn syrup, fructose, sucrose…corn based sugars can have many different names. While cornstarch can be a good source of carbohydrate, these corn sugars are inexpensive additions that do not do much for the nutritional profile. Most quality pet foods have eliminated them or reduced the amounts included in the foods.

Corn is used because it is both a nutritious and digestible product and because it is inexpensive.

The corn industry is subsidized by the federal government, making animal feed corn a viable option for pet foods. Corn is also generally considered to be one of the lower allergenic protein sources (based on food elimination trials), and is an ingredient of many food sensitive and hypoallergenic pet foods.

Corn meals and starches come in different grades. A high quality grade of corn gluten provides more nutrition and protein than a low quality meat by product, for example. The key, as always, is the balance of the pet food as a whole.

Soybeans

Soybeans are a legume like peas. Soy products are used in pet foods, although there is some controversy over their inclusion in them. Soybeans are used mostly for their protein content, although soy flours and meals also contain carbohydrates.

Soy can be added as soy flour, soybean meal or as soy protein concentrate (SPC). The challenge with soy is that many pets experience flatulence and belching if they consume too much of it. The SPC has had most of its carbohydrates removed, which reduces this effect. Soy flours and meals are high in protein and carbohydrates and generally have a balanced nutritional profile. However, these diets are also less palatable to dogs (they taste like beans) than the SPC.

Almost all commercial use of soybeans are from GMO soy plants.

In 2014, 82% of soy grown worldwide was from GMO plants, and this number is increasing. As the demand for non-GMO soy grows, there are more options for those who want GMO-free soy products.

Another problem with soybeans is that they contain things that can be potentially detrimental to some pets. Soy antigens can trigger an immune response, for instance, that can damage the intestines and reduce their ability to absorb nutrients. There are also questions about how soy can mimic some hormones (such as estrogen). We do not know what the long term effects of this is on our pets (or ourselves).

The pet food industry recommends that soy not make up more than 5-15% of a pet food, to reduce the side effects and the possible negative impact on pet health.

Exotic grains

Quinoa, freekeh! It seems like we rediscovery an ancient grain every few years. Although pet foods containing the exotic grains are not common, they are becoming more common. The nutritional profile for these foods will vary, depending on the grain and processing method.

We have not studied these ingredients in pet foods, and there have been no scientific trials done to see how dogs and cats do on them long term. They are more expensive than traditional grains and are usually grown outside the country and imported.

Dried beans, peas, lentils, chickpeas etc

Beans, peas, lentils and related ingredients are becoming more common in pet foods. They are typically seen in diets designed for suspected food allergy or food sensitive pets. These products are also used in “grain free” pet foods as a replacement for the grains. They are added to increase the carbohydrate and fiber content of the diet, and contain many nutrients and vitamins along with some protein.

The downside to using beans, peas and lentils is that they can cause an upset stomach in some pets. The fiber in these foods can react with the starches and ferment in the intestine, leading to the flatulence. Not all pets have this reaction, and many tolerate these ingredients very well.

A note about the use of lentils and chickpeas in pet food. These are recent additions to pet foods, and have not been studied using food trials or other testing.

Potatoes

Potatoes and sweet potatoes are both included in pet food as a source of carbohydrates and minerals. They contain almost no fat and are low in protein in their natural form. If the entire potato is used then they will also include some fiber. They are generally considered an easily digestible carbohydrate source, and are an ingredient in many food sensitive and hypoallergenic formulas.

Potatoes can be processed into potato powder, which is higher in protein than the complete potato. Potato can also be used as a thickener, in the form of potato starch.

Potato by product is the waste from other processed potato products. It is mostly used as an inexpensive fiber source in low quality pet foods.

Sweet potato is a newer inclusion, and has a different nutritional profile from white potatoes. However, the use of sweet potato as a primary carbohydrate source in pet foods has not been studied.

Beet pulp

When you think beets, you are probably thinking those lovely red globes you buy at the grocery store! Beet pulp, on the other hand, conjures up the image of a red slurry of beet juice and fiber. So what is beet pulp? And why is it in your pet’s food?

Beet pulp is produced from the sugar beet industry as a waste product. After all of the beet juice has been centrifuged from the solids (the juice is processed into sugar) you are left with handfuls of a brown fiber that look similar to hay.

Beet pulp has many micronutrients….for those animals able to digest it. It is used extensively as a feed supplement for horses. In pet foods, beet pulp is a source of insoluble fiber. It is used in weight loss formulas to help pets feel full while eating less food (since it is indigestible), and also in diets designed for pets with hairballs, constipation or other digestive disorders.

Beet pulp is also found in many “grain free” formulas, since they avoid using fiber from grain sources.

Cranberries, blueberries and other fruit and vegetables

It is very trendy to have fruits and vegetables pictured on pet food labels. Cranberries and blueberries are especially popular right now, but broccoli, kale and artichokes also show up. So should you be searching for a pet food that contains them?

The amounts of these products used in pet food is minimal, and has shown to have no health benefits. While drinking cranberry juice may help humans with urinary tract infections, there is no evidence that the inclusion of cranberries in pet food has any benefit to their urinary tract. Consumers would probably be better off using an approved cranberry supplement designed for this purpose.

The inclusion of berries and other fruits and vegetables like broccoli and carrots is about marketing, not nutrition. If you really want your pet to have them in their diet, you would be better off giving them the fruit or vegetables directly, or making your own pet treats that contain them.

Glucosamine, chondroitin and other supplements

There is a big market for pet foods that support joint health and skin! As our pets age (and become overweight), osteoarthritis and other joint problems often appear. So manufacturers have started adding joint supplements to their pet foo

The issue with using pet foods instead of a separate supplement (or supplements) is that the pet foods do not contain enough of the supplement to benefit the health of the pet.

The supplements are added in low enough amounts that a pets of all sizes can safely eat the food. This means that such supplements in pet food will be added in small, subtherapeutic amounts.

For instance, you can’t assume that a 5 pound dog will only ever eat half as much food as a 10 pound dog, or that a 100 pound dog will always eat exactly twice as much kibble as a 50 pound dog. Since supplements must be given in the proper dose (based on the weight of the pet) to have any effect, having a little bit of the supplement in the food does nothing for your pet.

If your pet needs a joint supplement, or suffers from skin issues, you would be better off buying a high quality pet supplement and giving it to your pet directly at the proper dose.

There is no evidence that supplements given at low levels contributes anything towards your pet’s health. If the supplement is taken in amounts lower than the therapeutic range, there are no health benefits.

This is another pet food ingredient that is more marketing than nutrition.

Now you know in detail the answer to the question “What is pet food made from?” Next up on the Food Trends series, I will talk about how pet food is marketed to consumers. Future topics include the envonmental impact of pet foods and the best way to store pet foods.