Pet Foods: Understanding Ingredients & Manufacturing
Pet Foods: Understanding Ingredients & Manufacturing
In this module, we will look at the different ingredients that feature in mainstream pet foods and how pet foods are manufactured.
Canine Nutritionist, David Jackson (founder of allaboutdogfood.com) sums up the situation with dog food manufacturers brilliantly:
"For far too long, pet food manufacturers have been able to get away with producing, frankly, awful foods for our pets. Somebody once said "don't blame the player, blame the game" and never has that been more appropriate. The game here is corporate capitalism and there is only one rule - make as much money as possible. The companies best able to cut costs while maximising income reign supreme and while that might work in other industries, it is not good news for our pets. The combination of low grade ingredients and elevated prices has been such a recipe for success for the 'The Big 3' pet food corporations* that most consumers aren't even aware that alternatives exist. And what's worse, the health problems that are often linked to low grade foods are now so widespread that many pet owners just disregard them as a normal part of a dog's life. So many dogs are living short, problem-filled lives and nobody's blinking an eye."
The Big Three are:
- Mars: Pedigree, Cesar, Chappie, Frolic, Kitekat, Pal, Nutro, Greenies, James Wellbeloved, Royal Canin, Sheba, Whiskas.
- Nestle: Bakers, Beneful, Beta, Bonio, Felix, Friskies, Just Right, ProPlan, Purina One, Purina Veterinary Diets, Winalot.
- Colgate-Palmolive: Hills Science Plan, Hills Prescription Diets.
Whilst they don't talk about it much, Mars also has a major shareholding in Tails.com.
Below is a list of ingredient terms that you may see described on pet food packaging:
Bone meal or ground bone is added to some dog foods as a natural calcium and phosphorous supplement. Its definition is very vague as it could come from any animal so if your dog is intolerant to a specific meat, bone meal is probably best avoided.
Although milk contains several beneficial nutrients, it also contains a high proportion of the sugar lactose. As in humans, many dogs have real difficulties digesting lactose and as a result milk products can bring on stomach pains, flatulence, diarrhoea and even vomiting. This condition is known as lactose intolerance. Lactose is also present in virtually all dairy products including cheese, yogurt, cream, whey and ice cream. If your dog has a sensitive stomach, dairy products are generally best avoided.
Hydrolysed Animal Proteins:
Proteins are formed from long chains of amino acids. By using enzymes and/or acids to perform a process called hydrolysis, these chains can be broken down into their constituent parts. The resulting substance, now called protein hydrolysate, hydrolysed proteins or simply digest, is then spray dried to form a powder which can be useful in pet food for a number of reasons.
The first and most common use is as a flavour enhancer since the hydrolysed proteins tend to taste and smell very attractive to dogs.
Second, while certain whole proteins might trigger allergic responses in some dogs, the much smaller molecules of protein hydrolysate go completely undetected by the immune system making them ideal for dogs that are highly prone to allergies.
And last, protein hydrolysate provides a useful source of relatively inexpensive but bio-appropriate amino acids.
Most often, protein hydrolysate is formed from 'slaughterhouse side streams', that is castoffs from the meat industry that, while not particularly appetising to us, serve perfectly well as a basis for hydrolysis. But some companies go much further using higher end meat ingredients or even whole animals for their protein hydrolysate.
Although protein hydrolysate is undoubtably useful, it has attracted criticism, due to the acidic/enzymatic reactions that are used to make it aren't really 'natural'. Another cause for concern lies in the fact that monosodium glutamate (MSG) can be formed during the hydrolytic breakdown of proteins. MSG is a very effective flavour enhancer which may cause dogs (and humans) to eat much more than is healthy and thus contribute to the growing pet obesity epidemic. When MSG is added to foods as part of a protein hydrolysate, it does not need to be declared on the label.
As with all meat ingredients, it's always better to make sure the animal species is specified. This means ingredients like 'chicken liver digest' or 'fish hydrolysate' are much better than simply 'digest' or 'meat hydrolysate'.
Eggs are a good source of low-cost, high-quality protein, fat and various minerals and micronutrients. Some of the fat is however cholesterol which should be kept to a minimum if your dog has high blood pressure or a history of heart problems.
'Freshly Prepared Meat' (as opposed to 'Fresh Meat'):
Producing 'Freshly Prepared Meat' involves several steps:
- Mechanical separation of the animal carcass through a deboning machine. A chicken carcass, for example, is a chicken, exclusive of feathers, head, feet and entrails and with the majority of actual meat (muscular tissue) removed for human consumption. It may be frozen.
- Grinding reduces particle size to produce a fine paste.
- Pasteurisation - the application of relatively low levels of heat (usually less than 100°C) for a short amount of time to eliminate pathogens and extend shelf life.
- Separation of water and fat via centrifuge. These can then be added back to the mixture depending on the nutritional specifications of the manufacturer.
- Concentration by low temperature vacuum evaporation.
What you are left with at the end of the five steps is a fairly viscous, beige-coloured 'meat slurry'. This is called 'Freshly Prepared Meat', which is certainly not 'Fresh Meat'.
Meat and Animal Derivatives:
According to European law, 'meat and animal derivatives' is defined as "All the fleshy parts of slaughtered warm-blooded land animals, fresh or preserved by appropriate treatment, and all products and derivatives of the processing of the carcass or parts of the carcass of warm-blooded land animals".
Clearly this is very loose and does not provide any clues as to what parts or even what animals are being used.
Meat Meal is a fine, dry, brown powder which, for many years, has formed the backbone of the dry dog food industry around the world. It can be listed in a number of ways, with or without the animal source. For example, meat meal from chicken could be labelled as 'meat meal', 'chicken meal', 'chicken meat meal', 'dehydrated chicken' or 'dried chicken'.
Meat meal is made from the parts of animals that aren't consumed by humans. This could be up to a third to a half of the original animal and generally includes residual meat, offal, connective tissues and in some cases bones.
If the source animal is not specified, the general term 'meat meal' means that it could have come from any species of 'warm-blooded land animal'. Broad terms like this are often used by dog food manufacturers instead of naming each ingredient either because the recipe regularly changes and/or because naming the ingredients would put customers off.
Tripe is the stomach of ruminating animals - usually from cows but also from sheep, goats, pigs and deer. It is highly nutritious and easy for dogs to digest. Tripe is rich in protein and fat and is a good source of essential oils.
'Green tripe' is tripe that has not been cleaned, bleached or otherwise processed. Green tripe is unique because it contains high levels of probiotics including friendly bacteria and digestive enzymes that can enormously benefit a dog's digestion.
The general terms 'cereals' and 'grains' can refer to any product of any cereal including wheat, rice, oats, barley, maize etc. Because it is impossible to know what 'cereals' refers to, we would suggest assuming the worst and avoiding foods with this ingredient. This is particularly important if your dog is prone to dietary intolerance as identifying and eliminating problem ingredients is impossible unless you know exactly what you are feeding.
There is a distinct difference between brown and white rice. There are some nutritional benefits to brown rice, which has the most nutrients.
White rice is simply brown rice that has been milled and polished to remove outer bran, germ and aleurone layers. Unfortunately, these layers contain the vast majority of the grain's nutrients and once removed the remaining white rice is almost entirely starch.
Garlic is an effective anti-fungal and anti-bacterial, it helps to eliminate intestinal worms and it acts as a deterrent to skin parasites like ticks. For these reasons, garlic can be a real help for dogs with all sorts of ailments and infections caused by bacterial, fungal or parasitic infection. And it's benefits don't stop there. Garlic has been linked with lowering blood sugar in diabetics, to aiding joint mobility and even to lowering blood cholesterol!
Peas have been a common dog food ingredient for years but the recent rise of grain free foods has seen their popularity skyrocket. Whilst they do have some vitamins and can be high in protein, too much pea content in any food means it starts looking less like a healthy addition chosen for its nutritional value and more like a filler chosen for its relatively low cost.
Potatoes are becoming more popular in dog foods as anti-grain sentiment continues to increase. Potatoes are predominantly made up of starch. There is some debate over the ability of dogs to digest starch efficiently but where it is digested it is broken down into its constituent simple sugars. For this reason, starchy foods like potatoes may not be the best choice for dogs with any health concerns, especially diabetes.
Tapioca (sometimes called cassava) is a starch extracted from the root of the cassava plant. It is often used as a carbohydrate source in grain free dog foods but due to its general lack of all nutrients other than starch, it is generally regarded as a low grade filler for dog foods.
Vegetable Protein Extract:
Vegetable protein extract (or isolate) is another term that doesn't shed any real light on what is in the food. It gives no indication of which vegetables are used, nor does it say how the protein is extracted, although the most common methods involve chemical reactions that are far from what most people would regard as 'natural'.
For dogs, vegetable proteins are nutritionally inferior to those found in meat. Common sources of vegetable protein include soya, maize and wheat which have all been linked to dietary intolerance and, in our opinion, should be avoided with sensitive dogs.
Some nutritionists have also speculated that vegetable protein extracts might also be a pseudonym for MSG (monosodium glutamate), the controversial food additive that some believe to be mildly addictive.
Soya beans (soya, soybean protein, soya meal) are high in protein and are often added to foods as a low-cost meat substitute. Unfortunately, the proteins in soya are much less bio-available to dogs than normal meat proteins meaning that far less can be digested and used. Soya has also been consistently linked by veterinarians to food intolerance and allergies and is therefore best avoided if your dog is very sensitive.
Artificial Preservatives and Antioxidants:
Artificial preservatives and antioxidants are far more widespread in pet food than most people imagine and although they certainly work at slowing down decomposition (in some cases giving pet foods a shelf life of over four years!), there are a whole host of concerns regarding their effects on health.
BHA (butylated hydroxyanisole or E320) and BHT (butylated hydroxytoluene or E321) are amongst the most common artificial antioxidants used in pet foods and are particularly worrying. One study at the University of Hamburg concluded that "all published findings agree with the fact that BHA and BHT are tumour promoters" and the Department of Health and Human Studies in the US found that BHA consistently produces tumours in both rats and fish . And the potential side-effects aren't just physical with one study finding a whole host of behavioural problems including increased aggression and "a severe deficit in learning" linked to BHA and BHT consumption in mice . Despite all of the evidence, both BHA and BHT are currently permitted in pet food (and human food) in both the US and in Europe.
Propyl Gallate (E310), an artificial preservative that is often used in conjunction with BHA and BHT, has also been linked with tumour formation in rats .
Another common preservative, Potassium Sorbate (E202) is listed as a skin, eye and respiratory irritant, has been shown to damage white blood cells and may also contribute to tumour formation .
One piece of good news for European pet owners is that Ethoxyquin or E324 (which was once one of the most widespread artificial antioxidants in pet foods and has a long history of connections with allergic reactions, skin disease, behaviour problems and far worse conditions) was 'suspended' by the European Food Safety Authority in April 2017 on the basis that it may cause damage to DNA and lead to cell mutation . This is, however, just a suspension and not a ban meaning that it could well return in time. Ethoxyquin is still widely used outside of the EU.
When a pet food manufacturer adds preservatives to its products, they have to be declared on the label. Oddly, though, they don't necessarily have to be listed alongside the other ingredients and can instead be buried within the typical analysis or elsewhere in the 'statutory statement' (the area on the label with all of the legally required info like ingredients, typical analysis, best before date etc) so you do need to keep your eyes peeled.
The law does provide rules for how ingredients should be listed but there is still plenty of wiggle room for manufacturers to add some spin here and there. So rather than simply stating that a food is, for example, 'preserved with BHA, BHT and propyl gallate', which might put off customers, they are much more likely to use far less worrying phrases like 'contains EU permitted antioxidants'.
It is actually impossible to say from the packaging alone whether some foods might contain artificial preservatives or not. This is because, while additives added by the manufacturers themselves have to be declared on the packaging, there is a legal loophole allowing artificial additives that were added to the ingredients before they reached the pet food factory to go undeclared. In fact, even if a food is littered with ingredients that have been individually treated with artificial preservatives before reaching the factory, the manufacturer can still legally claim that the food has 'no added preservatives' as they technically didn't add any!
Meat meal is a particular problem in this respect as it routinely has artificial preservatives added before it reaches the pet food factories - a fact that very few manufacturers manage to communicate to their customers.
You have to look closely, but the 'catch all' phrase of 'Contains EU Permitted antioxidants' is on this pack, but not with the rest of the ingredients.
Phosphoric acid (E338) is a clear, colourless liquid that is added to foods primarily as an acidifier but is also used effectively as a flavouring, emulsifier and to prevent discolouration. Studies have linked phosphoric acid to reduced bone density in humans making it a fairly controversial ingredient for both people and dogs. Although more work is necessary to confirm the link, our recommendation is to avoid foods with high levels of phosphoric acid.
Propylene glycol is a synthetic compound that absorbs water and can therefore be used to keep semi-moist dog foods and treats semi-moist. It also has anti-bacterial and anti-fungal properties making it suitable as a preservative.
Although propylene glycol has been approved as safe for both humans and dogs (but not cats due to its links to the feline condition Heinz body anaemia), it remains a source of controversy. This is partly due to regular links to asthma and allergic reactions and partly because propylene glycol's other commercial uses (including car antifreeze and in de-icing aircraft) don't inspire too much confidence in dog owners.
Sodium Tripolyphosphate (found in Dentastix):
Sodium Tripolyphosphate (also called STPP or E451) is added to dog foods as a preservative and to help moist foods to retain moisture so that they appear fresher for longer.
Although STPP is generally recognised as safe, it has been listed by the US National Institute for Occupational Safety and Health as a possible neurotoxin and is widely recognised as a mild skin irritant. We therefore recommend steering clear of foods containing STPP, especially if your dog is prone to skin problems.
Oils and Fats:
Umbrella terms like 'oils and fats' can make choosing the right food for your dog difficult as it gives very little indication of what is actually in the food. It could, for example, refer to beneficial oils or high quality animal fats, or it could be used for low grade, potentially harmful or highly processed oils.
Check out this video from Rodney Habib about how pet food ingredients may not be as expected...
This video from Rodney Habib and Dr Karen Becker discusses how Carbs/Starch/Sugars are not truly labelled on examples of pet foods in the USA, but the same methodology is used here by UK manufacturers as well.
Dry foods can be produced in a number of ways:
Extrusion is by-far the most common cooking method for dry dog foods. In the extrusion process, raw materials (usually pre-dried and ground ingredients in the form of powders) are mixed and passed through what is essentially a giant steam cooker. The mix is then passed through a 'die' where it is cut into the individual biscuits which are then rapidly dried with hot air, cooled and given a coating of oils to enhance their flavour.
The multiple levels of processing that are required to produce extruded foods, and particularly the high temperatures they involve, may destroy many of the natural nutrients contained in the ingredients, particularly vitamins, some amino-acids and enzymes.
Baking is an alternative cooking method that allows foods to be cooked at lower pressures than extrusion and therefore may leave more of the nutrients intact. Baking does, however, usually rely on a certain amount of wheat gluten to bind the biscuits. The process typically involves the biscuits passing slowly through a long oven atop a conveyor belt.
Cold pressed dog foods are still relatively new on the scene but are growing in popularity rapidly as they present all of the advantages of more conventional dry food processing but without the potentially damaging high temperatures. Ingredients do, however, still have to be dried and ground before pressing and some, like grains, also have to be pre-cooked so there is a certain level of processing, but the final stage is certainly a lot less intensive than extrusion.
Air drying takes things one step further as the ingredients usually start the process fresh rather than ground or pre-cooked. The food is exposed to a current of heated air, gently removing the water through evaporation which is thought to reduce the damage to proteins, vitamins and enzymes compared to conventional cooking methods. Some air dried foods need to be rehydrated by adding water so, while these packs might seem small, the volume of food you get from them is considerably larger.
Freeze dried foods are created by first freezing and then gently heating the ingredients within a vacuum to remove any moisture. In this way, the nutrients undergo very little damage making it arguably the most 'natural' form of dry food available. Freeze dried dog foods also tend to be eye-wateringly expensive but they do have incredible shelf lives without the need for any artificial preservatives. As with some air-dried foods, many freeze dried diets require rehydration with water before feeding.
David Jackson (https://www.allaboutdogfood.co.uk/dog-food-ingredient-glossary)
Rodney Habib (https://www.youtube.com/channel/UCXVR-WWoQ6J4kZNmPwdZkNQ)