The Pet Food Wars: In May 2014, Nestlé-Purina, the largest producer of pet foods sold in the U.S., filed a lawsuit against Blue Buffalo, a competitor. Among other things, the lawsuit alleged that Blue Buffalo’s marketing claims—that their foods contained no by-product meals—were false and disparaging to other companies’ products. According to the report of a testing laboratory hired by Nestlé-Purina, at least a few varieties of Blue Buffalo dry extruded foods (kibble) did indeed contain poultry by-product meal, comprising as much as 25 percent of the meal in some of its products. As is the way of the modern pet food industry, within days, Blue Buffalo responded with a countersuit of its own, accusing Nestlé-Purina of defamation, unfair competition and false advertising.
Central to this public (dog) food fight was the belief, strongly promoted by Blue Buffalo, that chicken or poultry meals are of superior nutritional value to by-product meals, and that high-quality dog foods contain the former and reject the latter. (It is of interest to note that Nestlé-Purina sidestepped the nutrient quality issue altogether in their lawsuit. Rather, they contended that Blue Buffalo had falsely promoted itself as being completely transparent to its customers.)
Deny, Deny, Deny: Initially, Blue Buffalo responded to the allegations with denial. Both companies launched public-relations campaigns that included strongly worded letters to consumers. However, in October, Blue Buffalo had to eat crow (meal?) when they announced that one of their suppliers, Texas-based Wilbur-Ellis, had mislabeled an ingredient, which resulted in the presence of poultry by-product meal in some of their foods. In the words of Blue Buffalo’s founder, Bill Bishop: “So, while their customers were ordering and paying for 100 percent chicken meal, at times they were receiving shipments that contained poultry by-product meal. As a result, we have stopped doing business with this plant.”
What is the truth? Are by-product meals lower in quality when compared with meals? Should discerning dog owners avoid chicken or poultry by-product meal and choose only foods that contain chicken or poultry meal? And is this a reliable way to distinguish between high-quality dog foods and foods of lesser quality?
Perhaps the best place to start is with an understanding of what a “meal” actually s.
Meals – The Protein Ingredient: Every ingredient that goes into a dog food contains a unique set of essential nutrients that it contributes to the finished food. In commercially prepared dry (extruded) dog foods, various types of meals are used to provide protein. These are classified in several ways.
- Plant vs. Animal Source: Examples of commonly used plant-based protein meals are corn gluten meal, soybean meal and pea protein (or meal). In general, plant-based protein sources are an inexpensive source of protein and are found in foods marketed to pet owners interested in economy. The quality of these meals is moderate to low in terms of amino acid balance and digestibility, although several protein sources are used to ensure that all essential amino acid needs are met. Animal-source protein meals, on the other hand, vary tremendously in both source—animal species—and in quality measures such as digestibility, amino acid content and amino acid availability.
- Species vs Generic Group: Animal source protein meals may be provided as species-specific meals or as generic animal groups. Examples of species-specific meals are chicken, bison, beef, salmon, venison, turkey and lamb meals. Alternatively, these meals may be classified more largely as poultry (contains varying amounts of chicken, turkey or duck), fish (contains multiple fish species), or meat (contains varying amounts of pork, beef or sheep). When you see a named species as the major protein meal ingredient, it generally indicates that the food is of higher quality (or at least a better-regulated product). Ingredient supply companies are required to keep these ingredient streams separate and designated, which means that sources are not mixed and translates to a more uniform product and greater regulatory oversight. Conversely, the generic term used to describe a group of food animals means that the meal may contain a mixture of species with no guarantee of any particular animal species or proportions in a given product. At the production level, this also means that several ingredient streams are combined, with varying sources of origin, regulatory oversight and quality attributes.
- Meals vs. By-Product Meals: The term “by-product” is the designator receiving the most attention. It is important to know that on pet food labels, this term is only applied to chicken and poultry meal. And, the distinction is largely bureaucratic; the Association of American Feed Control Officials (AAFCO) sets the definitions for ingredient terms and they have not designated a by-product meal term for any other animal protein meal. The closest they’ve come is “meat” meals versus “meat and bone” meals; the latter contains bone, which can reduce its quality as a protein source. (More about the purported differences between chicken/poultry meal and by-product meal later).
Meals are Produced via Rendering: Rendering is a cooking process that converts slaughterhouse products that have been deemed unfit for human consumption into a form that is regulated as acceptable for use in pet foods. Generally, animal parts used for rendering are those not typically consumed in our Western diet: organ meats such as spleen, kidneys, liver; stomach and intestines; varying amounts of bone; and, in the case of poultry, necks, feet and heads. In addition to slaughterhouse waste, “spent” layer hens from the egg industry and food animals found to be too diseased or injured to pass inspection for use as human foods may also end up at the rendering plant. Classified during the slaughter process as “inedible,” these parts are redirected into an alternate supply stream and are handled, transported and processed differently than those intended for human consumption.
The Process: During the rendering process, the combined components are ground, mixed and heated to a high temperature (220° to 270° F), which cooks and sterilizes the mixture, effectively killing the microbes that are present. Sterilization is absolutely necessary because refrigeration is not required for the handling or transport of inedible foods. The resulting slurry is centrifuged at high-speed to remove lipids (fat). The removed fat is further processed and eventually is sold separately as chicken, poultry, or animal fat. The mixture that remains is dried and ground to a uniform particle size that ultimately has the appearance and texture of dry corn meal. Animal protein meals are very low in moisture and contain between 55 and 65 percent protein, making them a rich source of protein when included in a pet food.
Why use Protein Meals? From a commercial perspective, meals are well suited for use in dry foods because they can be stored and transported easily, and have the low moisture content necessary for extrusion processing. By comparison, high-moisture protein ingredients, such as “fresh” chicken (or other meat), contribute only small amounts of protein by weight to the end product because the water is cooked off during the extrusion process. These ingredients may be listed first on a food’s ingredient list simply because they contain more than 65 percent water, and ingredients must be listed in predominance by weight at the time of processing. In reality, it is the dried meals, usually found within the first three to five ingredients on the list, that provide the bulk of dietary protein in dry dog foods.
It Aint’ your Grandma’s Roast Chicken: According to AAFCO, the term “meal” refers to the “dry, rendered product from a combination of clean flesh and skin with or without accompanying bone, derived from the parts of whole carcasses of [chicken/poultry], exclusive of feathers, heads, feet and entrails.” (1) Although this definition seems to suggest that meals are produced from the same parts of the chicken that make it to the supermarket for human consumption, this is simply not true. As mentioned previously, animal protein meals are produced from slaughterhouse waste and other food animals that are deemed “not for human consumption” (i.e., inedible).
In the case of chicken, these waste products are predominantly “chicken frames,” the remainder of the chicken’s body after the parts destined for human consumption have been removed. More than 70 percent of a broiler chicken ends up in the supermarket, leaving about 30 percent in the frame, which is made up of a bit of muscle meat plus a lot of connective tissue and bone.
None of the animal protein meals that are used in the production of dry dog foods are produced from edible (human grade) meats. This is because rendering plants are in the business of taking inedible animal parts and converting them into a form that can be fed to non-human animals. Chicken meal comes from chicken frames that are designated as not for human consumption, not from supermarket chicken.
The Deal (with By-Product Meal): By-product meals are composed of exactly the same chicken components found in meals, but by-product meals may also contain varying quantities of heads, feet and viscera (guts). Therefore, the difference between a chicken (or poultry) meal and its respective by-product meal is the inclusion of heads and necks, feet, and guts (viscera) in the latter and the exclusion of those body parts from the former. On the face of it, this appears to be an obvious quality distinction. After all, any product that has heads, feet and guts in it not only sounds yucky, but certainly must also be of poor quality, right?
Well … it depends.
Given this definition, the general (and understandable) perception is that meals will be of higher quality than by-product meals. This is clearly the conclusion that Blue Buffalo and other pet food companies that make “No By-Products!” claims on their labels are banking on. However, consistent and substantial quality differences between the two ingredient types are not reported. The fact is that the inclusion of additional body parts (heads, feet and guts) in by-product meals can reduce, maintain or improve the quality of a meal (2).
Beaks, Feets and Guts, Oh My! These three additional parts, although certainly not very appetizing to most people, have varying nutritional value as food ingredients. First, the protein quality of viscera (internal organs and intestinal contents) is similar to that of chicken flesh components included in very high-quality chicken meals (and to what humans consume in a chicken dinner). In other words, including organ meats and intestinal contents in a by-product meal does not negatively affect the meal’s protein quality and may even improve it in a poor or average quality meal. Second, the inclusion of chicken heads in the mix results in a slight reduction in nutritional quality. This is because chicken brains are highly digestible while chicken skulls, being comprised of bone, are less so. So it appears to be a zero sum game when it comes to the added chicken heads. Last – chicken feet. As a food ingredient that is intended to provide dietary protein, feet are simply bad and have measured quality values similar to feeding connective tissue or bone residue.
FEET (BAD) HEADS (LESS BAD) GUTS (BETTER)
Collectively speaking, including additional body parts in a by-product meal may affect the resultant product’s protein quality either positively or negatively when compared with its corresponding meal. The influence depends largely upon the actual proportion of the three different body parts that are included in the end product: if there are lots of guts, quality improves. Heads: could go either way. Feet: bad news.
And, by the way, specifics on the type and quantity of these additions is information that consumers are never privy to.
So, Why All the Hype? Studies of the digestibility and protein quality of meals and by-product meals have found that as a group, meals are slightly more digestible and contain slightly more available essential amino acids than their associated by-product meals (3,4). However, there is also a lot of overlap between the two ingredient groups, meaning that a given meal may be better, equal to or even lower in quality than a given by-product meal.
Overall, the differences that have been found are neither dramatic nor worthy of the hysteria that seems to accompany the word “by-product” among dog owners and some pet food companies. Therefore, the marketing hyperbole and excessive “patting oneself on the back” by companies that include meals but not by-product meals should be viewed by all dog owners with a hefty dose of skepticism. True, there is some difference, but probably not enough of a quality difference to warrant the inflammatory language and excessive claims that are being made by companies jumping on the by-product-free bandwagon.
Draggin’ Out the Ol’ Box Again: I would suggest that this exaggeration of difference has occurred (and been actively promoted) because there are so few available ways for dog owners to accurately assess the quality of ingredients, especially protein ingredients, in commercial pet foods. As a result, this single AAFCO-defined difference (meals vs. by-product meals) has caught on like a house on fire, with marketing campaigns flinging additional gasoline to fuel the flames and causing this distinction-without-a-difference to garner more importance than it comes even close to warranting.
It is an unfortunate paradox that one of the most important nutrients for dogs (protein) is supplied by a type of ingredient (protein meals) that consumers have almost no way of evaluating. This is especially concerning given that animal-source meals can vary tremendously in the components that make them up and ultimately in their quality (i.e. in nutrient content and digestibility). The three designators discussed previously —plant- vs. animal-source, species vs. generic and meal vs. by-product meal — are the only protein-ingredient quality designators available to consumers. This might not be an issue if they were in truth the most important quality differences among animal protein meals. However, they are not. Animal protein meals differ in ways that are invisible to consumers and can significantly influence the quality of the foods in which they are used:
- Bone and connective tissue: Animal-source protein meals contain varying amounts of bone and connective tissues (this pertains to both meals and by-product meals), which affects the product’s protein quality and mineral balance. Bone matrix and connective tissues contain the protein collagen, which is poorly digested and utilized when included as a dietary protein source, and bone contributes excess amounts of calcium and several other minerals. Meals that are high in collagen and minerals from bone and connective tissues are of lower quality than those that contain a larger proportion of muscle meat.
- Transport and contamination: Because inedible food products are not refrigerated or subject to the same handling regulations as foods destined for human consumption, both the handling and transportation of raw materials can affect the quality of the end product. If rendering is conducted at the slaughterhouse of origin, the meal is usually produced within a day or two following slaughter. However, when raw materials are transported to a rendering plant in another location, the time spent during transport under unrefrigerated conditions can lead to increased microbial contamination and oxidative damage.
- Processing: Differences among rendering plants also exist and are important for the end product. High temperatures or excessively long cooking can damage a meal’s protein, making certain essential amino acids less digestible and available.
- Supplier integrity: Finally, as seen with the Blue Buffalo case, pet food companies are at least somewhat dependent upon the integrity and honesty of their ingredient suppliers. A division within the animal feed industry designates some meals as pet-food grade and others as feed grade, with the former containing a lower percentage of ash (minerals) (5). In addition, some pet food companies select only meals that meet a particular standard, while others impose additional refining methods on their protein meals to increase digestibility and improve protein quality.
- Tests that we do not hear about: Various analytical tests are used to measure a meal’s digestibility and amino acid availability, and many pet food companies also routinely measure the digestibility of their foods using feeding trials. However, this information is not easily available to consumers, and pet food companies are under no obligation to accept or reject meals of different quality levels or to share such information with consumers.
To date, there is no way for pet owners to differentiate among dry (extruded) dog foods that use high-quality animal protein meals and those that use poor-quality meals, other than the cost of the food and the three designators discussed previously. You can contact the company and specifically ask for information about the food’s protein digestibility and quality, of course. However, you may be disappointed. While researching my book Dog Food Logic, I contacted the manufacturers of more than 30 different pet-food brands and requested protein and diet digestibility information for each of the products. I received no reply at all from the majority of companies and useful information for just two of the brands.
Are There Any Other Options? In today’s innovative market place, there are indeed a few. Two other animal-source protein ingredients (in addition to fresh meats prepared at home) are those that are either freeze-dried or dehydrated. Freeze-dried ingredients are typically used in raw food diets, but can also be cooked prior to packaging. Dehydration usually uses heat treatment to kill microbial growth and so moderately cooks the meat. These sources are likely to be of higher quality and digestibility because they have not undergone the high heat processing that meals are subjected to.
If they are human-grade meats, all the better, as this means that the ingredients and the end-products were handled and produced using the same regulatory oversight as required with human foods. However, with a few exceptions, neither freeze-dried nor dehydrated meat sources are routinely used as the primary protein source in dry, extruded foods. Nor have I found a source of dried protein meals produced using human grade (i.e., edible) meat sources and human food processing methods. To do so (and to promote them as such) would add a dimension of choice and distinction regarding the quality of dry dog food that does not exist today. Dry extruded dog food continues to be the most popular type of dog food sold in the U.S., and I believe such products would be welcomed by owners willing to pay a bit more for a better regulated and higher quality food.
Take Away for Dog Folks: While rendered animal meals can be of high quality and can provide an excellent protein source in dry dog foods, if the animal-source meal has been poorly sourced, handled, processed, or regulated, its protein can be damaged, making it a poor source of essential amino acids for dogs and reducing the digestibility and quality of the entire diet. Unfortunately, there is no way for consumers to tell from a food’s label if the meal used is of high, moderate or low quality. Because meals make up the bulk of protein in dry dog foods, information about their quality, and by extension, how nourishing they are, is the most important consideration that we should be concerned with when we look at an ingredient list.
The problem is, despite what companies beating the “No By-Products” drum would like us to believe, we have no way of knowing which animal protein meals are better than others.
- Association of American Feed Control Officials. 2010. Official Feed Definitions; pp. 326–322.
- Aldrich, Daristotle. 1988. Petfood and the economic impact. Proceedings of the California Animal Nutrition Conference, Fresno, CA; pp. 1140–1148.
- Cramer, Greenwood, Moritz. 2007. Protein quality of various raw and rendered by-products commonly incorporated into companion animal diets. Journal of Animal Science 85:3285–3293.
- Locatelli, Howhler. 2003. Poultry byproduct meal: Consider protein quality and variability. Feed Management 54:6–10.
- Dozier, Dale, Dove. 2003. Nutrient composition of feed-grade and pet-food-grade poultry by-product meal. Journal of Applied Poultry Research 12:526–530.
*A version of this article was published in the Spring, 2015 issue of The Bark.