Does Convenience Dictate our Choice of Petfood?

By John Birch

The basic choice we have when we look for a petfood for our dog or cat is whether to go for a dry complete mix, or a moist/canned food. The main criteria to consider are the place you shop, how much money you would like to spend and the level of convenience, palatability and digestibility desired.

The difference in moisture content among the various types of pet food impacts the nutrient density of the products or the amount of nutrients per pound of food. As the water content of the diet increases, the amount of protein, fat and other essential nutrients decreases. That means the animal must consume a larger portion of the high moisture products to receive the nutrition they need, but it also makes comparisons between the different types of food difficult.

Canned or pouch foods offer highest palatability and the highest cost per serving when compared to the dry and soft-moist products. However, they are less convenient to use, as once opened any unused food needs to be stored in the refrigerator.

The main advantage of dry foods is convenience, as wastage is minimal, cost is low in comparison to canned or pouch foods, and it is claimed that the grinding action of eating dry food helps to keep teeth clean (again disputed by some.)

Carbohydrates constitute between 30 percent and 40 percent of dry cat food. Some have been concerned that this unnatural diet is harmful to cats and leads to increased incidence of diabetes. Wet cat food, on the other hand, is high in protein and more similar to a natural carnivore diet.

Canned or Pouch Food

Obviously it is difficult to give anything other than a guide to the production process, as methods and machinery vary. Also, some products are presented in a 'loaf' form and others as chunks in 'gravy'. But a typical processing scenario for canned or pouch food would be:



Meat products are thawed, pre-chopped and stored in silos containing no more than half an hour's production.

Then as soon as they enter the production chain, the ingredients required for the recipe are dosed and ground.

An endless screw collects and weighs the components.

The resulting mass is then sent to the thin pre-cutters and mixers. At this stage, minerals, cereals and vitamins as required are added to ensure a balanced diet for the cat or the dog.

The product is then packed in cans, metal trays or sterilised pouches

Bear in mind that those 'meaty chunks' in your pet's food may not be all that they seem! Much of this material is manufactured from ground up meat which is extruded to give the impression of meat fibres. Soya protein isolates can help to give these chunks more body by holding onto water.

Dry Food

Again it is difficult to give anything other than a guide to the production process, as methods and machinery vary, but the simplified method below is common:



The ingredients required for a given recipe are first weighed, ground and mixed.

Production is achieved through a special technology : cooking-extrusion. This involves exposing the mixture of animal and vegetable materials to the combined effects of pressure and temperature for a short period, making the product highly digestible as it ensures the complete cooking of the starch.

Dry foods may then be sprayed with fat in order to complete their composition and increase palatability.

Because dry foods are exposed to the air, and not sterilised in a can or pouch, they need to have anti-oxidants and preservatives added to ensure that the product does not go rancid. These can be chemical (declared as 'EU approved antioxidants' and could be BHA, BHT or Ethoxiquin for instance) or natural (Vitamin E or C, and an extract of Rosemary Oil are common),

Natural antioxidants are generally less stable and more prone to degredation if subjected to high temperatures. They are also more expensive to use!

The author, who originally trained as a food technologist has, in his time owned dogs, cats, hamsters and birds, sold pet food and spent the past decade marketing it. Now down to one cat, one dog and running Pet Food Choice, a website full of information on pet food choices, money-saving ideas and much more - http://www.pet-food-choice.co.uk