Pet
Food
Review

Pet Food ingredients (What you need to know!)

(Concentrating on dog and cat food which seem most contentious!)

or

William Burkholder, D.V.M., Ph.D who is the pet food specialist for the US FDA Center for Veterinary Medicine, and knows a thing or two about the subject recommends looking not only at the list of ingredients on a pet food label, but also the contact telephone number of the manufacturer. Why? So that you can give them a ring and query anything you are not sure about.

The ingredients list on the label is where the pet owner makes up his or her mind about whether they like what they read. Those who do or do not want to feed a certain ingredient can look to make sure it is included or excluded.

See also - pet food scares

'Yes' or 'No' to animal by-products?

Some prefer to say no to animal by-products, which may contain heads, feet, viscera and other animal parts not particularly appetizing, and from various species. But protein quality of by-products can actually be quite good, so that may not necessarily be the main bone of contention (excuse the pun!).

At the end of the day you do have to ask yourself the question... Am I feeding myself or an animal? If it's an animal (and I guess it is) then is this something that an animal might actually find perfectly acceptable.

It is true that we're humanising our pets - convincing ourselves that we sholdl be only feeding them what we would eat. Just a thought!!

Meat and animal derivatives

Meat and animal derivatives - sounds tasty, doesn't it? This tends to be seen as an ingredient at the cheaper end of the pet food market, and as a source of protein. Meat and animal derivatives are legally defined in the Feeding Stuffs Regulations 2005. They are sourced from animals which have been inspected and passed as fit for human consumption and are the parts of the animal which are surplus to the requirements of the human food industry in the UK eg. heart, lung, or muscle meat, which may not be traditionally eaten by people in this country.

This material will generally be rendered down and added as dried meal to the recipe (see below for description of this process)

Although manufactuers are happy to tell you that the meat they use is human grade and comes from the human food chain, let's be clear that this is not the best fillet steak or free range chicken breast. Meat producers take as much as possible from a carcase to make products for the human market, it's more profitable- what's left is what you would probably not want to buy if it was on the butchers or supermarket shelf!

Cereal by-products

Headlines such as 'May 4, 2007 -- Cereal Byproducts Company is announcing today that the FDA has determined that there are melamine and/or melamine derivatives in the rice protein concentrate produced by a single source Chinese supplier' do nothing to give confidence to consumers!

Cereal by-products, a cheap source of carbohydrate and vegetable protein by their name and definition are 'by-products' of the human food industry, not usable for human food and could come via bakery/breakfast cereal or similar production. They will possibly be mixed sources of cereal, and may be lower grade than the straight cereals used in premium brands. I'm guessing that waste product from the baking industry would fall into this category.

Meat Meal

Meat Meal (chicken, Lamb or fish for example) is another ingredient that some pet owners don't like the sound of. By-products of the human food chain (carcases with some meat protein remaining) are rendered (heat processed), which removes the fat and water from the product. Meat or poultry meal can contain parts of animals not normally eaten by people.

The rendering process in it's simplest form is shown on the left - you probably don't want a detailed description (if you do try this one at Wikipedia!)

Suffice to say, this is a huge business converting waste animal tissue into stable, value-added materials for several industries as well as for pet food.

The article from Wikipedia interestingly points out that rendering is one of the oldest stablished recycling processes - taking what would otherwise be waste materials and makes useful products such as fuels, soaps, rubber, plastics, etc. At the same time, rendering solves what would otherwise be a major disposal problem. As an example, the US recycles more than 21 million metric tons annually of highly perishable and noxious organic matter. In 2004, the U.S. industry produced over 8 million metric tons of products, of which 1.6 million metric tons were exported.... food for thought, perhaps!

The UK Pet Food Manufacturers Association (PFMA) states that it uses those parts of the carcass which are either surplus to human requirements or which are not normally consumed by people in the UK. Companies which are members of the PFMA operate their own quality assurance policies including strict specifications for material supplies, routine testing of all incoming materials and the use of vendor assurance schemes (and audits) to monitor their suppliers. The British pet food industry also uses sources of meat and meal from the UK, USA Canada, Australasia and various European countries. All materials imported must comply with the strict British legislation.

UK manufacturers only use materials from animals which are generally accepted in the human food chain. They do not use horsemeat, whales or other sea mammals, kangaroos or a number of other species not eaten by humans. It does use beef, lamb, poultry, pork, fish, shellfish, rabbit and game. The PFMA practice of only using materials derived from animals passed as fit for human consumption is now incorporated into the Animal By-Products Order and PFMA member companies using animal material derived from the UK are recommended to only buy from and sell to companies registered under the Animal By-Products Order.

Fats and Oils

A supply of energy and essential fatty acids. Important for optimal health, including kidney function and reproduction, and a glossy coat. There are 2 different types of essential fatty acids – omega 3 & 6 and 3 recognised EFA’s – linoleic, alpha linolenic and arachidonic acid. These are required in small quantities for optimal health and cannot be synthesised by dogs and cats from other fats. Arachidonic acid an essential nutrient for the cat and is only available from animal sources. Some fats also supply a source of vitamins A & D.

Poultry (or Chicken) Fat

Primarily obtained from the tissue of poultry in the commercial process of rendering or extracting. According to US regulations It shall contain only the fatty matter natural to the product produced under good manufacturing practices and shall contain no added free fatty acids or other materials obtained from fat. It must contain not less than 90 percent total fatty acids and not more than 3 percent of unsaponifiables and impurities.

Note: when given a choice, people generally pick a food preserved with Vitamin E and have every reason to expect that the food has no other preservatives in it. Well, sorry. It still could have other chemical preservatives in the food if the manufacturer purchased the fat and protein from suppliers who, prior to shipping to the manufacturers, added chemical preservatives. So the food manufacturer's label says, "preserved with Vitamin E" because that's all they added. You have no way of knowing if prior to what the manufacturer did, someone else added other preservatives.

Digest

Quite simply, most dried pet foods would have a low palatability without the use of flavourings - that is, your pet wouldn't eat them quite as enthusiastically. Digest is a flavouring or palatability enhancer which is often sprayed onto the kibble in small amounts to make the food more appetizing. There's nothing intrinsically wrong with it as an ingredient, and as long as the rest of the ingredients together make a complete and nutritious food then it can be thought of as spraying on a little bit of gravy.

Most pet foods will have digest added to the recipe, but not all declare it on the ingredient declaration, which might be thought a little naughty! If in doubt ask the manufacturer of your current food.

What is it? Well, to quote from the US AAFCO definition 'Animal digest - A material which results from chemical and/or enzymatic hydrolysis of clean and undecomposed animal tissue. The animal tissues used shall be exclusive of hair, horns, teeth, hooves and feathers, except in such trace amounts as might occur unavoidably in good factory practice and shall be suitable for animal feed. If it bears a name descriptive of its kind or flavor, it must correspond thereto.'

The only arguement, from the standpoint of feeding a natural diet is whether the manufacturing process to create the digest (chemical or enzymatic hydrolysis) can be considered 'natural'... and if a manufacturer is wary of including digest in their ingredient declaration, even though they use it, what does that say about their confidence in answering this question?

Digest of Beef
material from beef which results from chemical and/or enzymatic hydrolysis of clean and un-decomposed tissue. The tissues used shall be exclusive of hair, horns, teeth and hooves, except in such trace amounts as might occur unavoidably in good factory practice.

Digest of Beef By-Products
material from beef which results from chemical and/or enzymatic hydrolysis of clean and un-decomposed tissue from non-rendered clean parts, other than meat, from cattle which includes, but is not limited to, lungs, spleen, kidneys, brain, livers, blood, bone, partially de-fated low-temperature fatty tissue, and stomachs and intestines freed of their contents. It does not include hair, horns, teeth and hoofs.

Digest of Poultry By-Products
material which results from chemical and/or enzymatic hydrolysis of clean and un-decomposed tissue from non-rendered clean parts of carcasses of slaughtered poultry such as heads, feet, viscera, free from fecal content and foreign matter except in such trace amounts as might occur unavoidably in good factory practice.

Sugar Beet Pulp

Here's an ingredient that is seen more often these days in dog food particularly, and on the surface seems to be an odd choice of ingredient. What's it there for?

The answer depends upon who you are talking to! To some this is a cheap filler, to others it's a source of dietary fibre.

Fiber is the part of carbohydrates that can not be digested by the dog. Depending on nutritional goals, varying levels of dietary fibre with different properties are necessary to make a highly processed food source like commercial kibble "work", since a dog's digestive tract is not designed to process a diet with such high levels of carbohydrates - most commercial dry foods contain 40-50%, low quality ones even more.

Depending on the inclusion of ingredients that are naturally high in fibre (e.g. brown rice, oats, certain fruits or vegetables), a food may or may not include specific, isolated types of fibre.

Beet Pulp, it is claimed, is a very gentle, beneficial source of fiber that is not only generally very well tolerated, but also has specific properties that make it suitable as a source of nutrition for the beneficial bacteria that reside in the intestinal tract. The sugar is almost completely removed, what is left in the pulp is only about 1/5 the amount of sugar that you would find in a serving of carrots of equal size. It is also colorless and does not turn a dog's coat turn red, like urban legends claim.

The argument that beet pulp is an "unnatural" ingredient is often brought up, but people who present this complaint seem to forget that it is also not natural for dogs to eat highly processed commercial products with a carb content of generally 40% and more, and a moisture content of only around 10% as opposed to a more natural 60-70%. Added fiber is required to make such formulations work for the pets who eat a dry diet. (source dogfoodproject.com)

Salt

Sodium is an essential nutrient for cats and dogs. Good sources of sodium in pet food include meat, poultry, fish, and eggs. Sodium may also be included in prepared pet foods in the form of table salt (sometimes listed on the ingredients panel as salt) to enhance taste.

NB The National Research Council lays down guidelines on sodium levels for dogs and cats. Although sodium levels in human food can present a human health issue due to the risk of hypertension, sodium levels in prepared pet food are not a cause for concern in healthy adult dogs and cats. The physiological make up of a pet animal is quite distinct from that of a human. Healthy dogs and cats are able to consume diets with higher sodium levels than those found in most prepared pet foods without increased blood pressure or gain in body water. While a higher sodium intake may cause increased thirst and water consumption, the extra sodium is excreted in the urine (Luckschander. N, Iben. C, Biourge. V, Journal of Veterinary Medicine 16: 354 ). In pets with disorders such as heart or kidney disease, the use of reduced salt diets may be advised. Such disorders must be discussed with a vet.

Sugars

The term "various sugars" is a category description, which may refer to sucrose (cane sugar, commonly known as table sugar), fructose and glucose, all of which are natural products present in fruit, vegetables and cereals.
Some manufacturers may add sugar to pet foods as an energy source. Through digestion dogs and cats can easily convert sugar in to usable energy.
Manufacturers may also add very small amounts of sugar to assist with the cooking process.

Vitamins and Minerals

All so-called 'complete foods' need vitamins and minerals adding (just as breakfast cereal is fortified) to ensure that long term feeding doesn't lead to deficiences. The only arguement seems to be, for those of a natural persuasion, whether these should be from a natural or synthetic source.

It has to be said that most so-called Holistic products in the UK use commercial and manufactured vitamin and mineral mixes to ensure that the food contains a consistant nutritional balance of these essential nutrients. Some contain natural sources of vitamins and minerals, which would seem to be where, in the US, AAFCO would like natural products to be.

There are, however some who warn against this, based on inconsistencies in the natural alternatives. Burns pet Nutrition state 'Natural ingredients, by definition, are very unlikely to contain consistent quantities of these nutrients (e.g. due to seasons, weather, soil type, etc) therefore, supplementation with exact quantities is necessary in order to avoid chronic deficiencies or toxicities...For example, seaweed can contain high levels of magnesium which interferes with the uptake of zinc and copper from the diet. Also, in order to meet the minimum levels of less prevalent nutrients such selenium; you would need to add high quantities of seaweed, which could in turn lead to toxic levels of other nutrients, such as iodine.'

Chemical and natural preservatives/antioxidants

Can you think of making a baked product containing between 10 - 20% fat which you place into a paper sack and leave around for 12 months at room temperature AND expect it to be edible at the end of that time period?

I guess the answer is 'No!' because the food would have gone mouldy and rancid by that time. That's why you need preservatives/antioxidants to stop that rancidity or at least slow it down. Fat that has gone rancid produces ketones and aldehydes which are not particularly good for health!

Some consumers try to avoid pet foods with synthetic preservatives, such asbutylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and ethoxyquin. Ethoxyquin, in particular, has been hotly debated. Current scientific data suggest that ethoxyquin is safe, but some pet owners avoid this additive because of a suspected link to liver damage and other health problems in dogs.

(read our extended article on antioxidants in pet food)

Many products today are preserved with naturally occurring compounds, such as tocopherols (vitamin E) or vitamin C. However, these products generally have a shorter shelf life than those with synthetic preservatives, especially once a bag of food is opened. Some experts recommend that if you are buying a naturally preserved food that you make sure it is no longer than three months old, or has at least 9 months on the use by date (check the best before date)

Anti-Mould additives

You might also find magnesium oxide & calcium propionate added to a pet formula (though rarely in this country if ingredient declarations are to be believed) and these are anti-mould additives.

in the US in 1995 Nature's Recipe pulled thousands of tons of dog food off the shelf after consumers complained that their dogs were vomiting and losing their appetite. Nature's Recipe's loss amounted to $20 million. The problem was a fungus that produced vomitoxin, an aflatoxin, which is a subset of mycotoxin, a poison given off by mold contaminated the wheat.

Generally, if the moisture content of a dry food is consistent then you shouldn't get mould problems. This might be more of a problem in tropical climates.

Other additives

Apart from the ones listed above there will be other additivies used during the manufacturing of a lot of pet foods, simply to aid the cooking process (the same is true of manufactured human foods). Colours are pretty obvious in some pet foods, but there will also be some processing aids used which won't be on the ingredient list. In the US one organisation has listed the following as being used in the pet food manufacturing process (not all manufacturers will use these, let's be ABSOLUTELY clear about that!)

Additives in (some) Processed Pet Foods:
Anti-caking agents, Flavoring agents, pH control agents, Anti-microbial agents, Flour treating agents, Processing aids, Anti-oxidants, Formulation aids, Sequestrants, Coloring agents, Humectants, Solvents, vehicles, Curing agents, Leavening agents, Stabilizers, thickeners, Drying agents, Lubricants, Surface active agents, Emulsifiers, Nonnutritive sweeteners, Surface finishing agents, Firming agents, Nutritive sweeteners, Synergists, Flavor enhancers, Oxidizing and reducing agents, Texturizers