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What is dog food?

Dog food is plant or animal material intended specifically for consumption by dogs or other canids. Dog treats will be covered later.

Some people make their own dog food from scratch, many others rely on commercially manufactured dog food. The main thing is that the dog gets the well balanced diet that it needs.

Unfortunately dogs will eat just about anything and everything in any quantity. Making sure they get the right amounts of nutrients and calories for their energy needs is up to us. The right number of calories depends on size, breed, age and level of exercise. Puppies, adult dogs, senior dogs, pregnant and lactating bitches all have their own nutritional requirements.

Commercial dog food

Most commercial dog foods are made from materials unusable or less desirable for human consumption. These may include:

  • Meat by-products or digests
  • Meat-and-bone meals
  • Grain by-products

It generally contains meat byproducts and cereals with added vitamins, and minerals. By its water content, commercial dog food can be categorized into following types: dry, semi-moist, and moist.

Dry dog food contain less than 14% water. It is made in two different ways: extruding and baking. The main types of dry dog food include: pellets, biscuits, flakes. They may be labelled "complete" or "supplementary". A supplementary food must be fed along with other foods to ensure that all nutritional requirements are met; biscuits and flakes tend to be supplementary foods intended to be eaten with meat

Semimoist foods are stabilized with sugar, salt and chemical preservatives (propylene glycol). Unfortunately the sugar can mean dental problems for your dog.

Tinned dog food contains 70 to 85% water. It is sterilized during processing and packaged in waterproof, airtight containers that keep microorganisms out. The products are usually formulated with meat and offal (by-products of the butchering process not usually consumed by humans) that are processed as fresh or frozen ingredients. The canned-food industry began in 1923 in the United States and developed extensively beginning in the 1950s

Raw Materials

The primary ingredients in commercial dog food are by-products of meat, poultry, and seafood, feed grains, and soybean. The animal parts used for pet food may include damaged carcass parts, bones, and cheek meat, and organs such as intestines, kidneys, liver, lungs, udders, spleen, and stomach tissue. Cereal grains, such as soybean meal, corn meal, cracked wheat, and barley, are often used to improve the consistency of the product as well as to reduce the cost of raw materials. Liquid ingredients may include water, meat broth, or blood. Salt, preservatives, stabilizers, and gelling agents are often used and gelling agents to allow greater homogeneity during processing and also control the moisture. They include bean and guar gums, cellulose, carrageenan, and other starches and thickeners. Palatability can be enhanced with yeast, protein, fat, fish solubles, sweeteners, or concentrated flavors called "digests." Generally, artificial flavors are not used, though smoke or bacon flavors may be added to some treats. Most manufacturers supplement pet foods with vitamins and minerals, since some may be lost during processing.

Additional ingredients used for dry foods include corn gluten feed, meat and bone meal, animal fats, and oils. For a meat-like texture, dry foods require more amylaceous, or starch ingredients; proteinaceous adhesives, such as collagen, albumens, and casein; and plasticizing agents. Semi-moist pet foods usually require binders, which come from a variety of sources, such as gels, cereal flours, sulfur-containing amino acids, lower aLkyl mercaptans, lower alkyl sulfides and disulfides, salts, and thiamin. Semimoist products may also incorporate soybean flakes, bran flakes, soluble carbohydrates, emulsifiers, stabilizers, and dried skim milk and dried whey.

Antioxidants are often used to retard oxidation and rancidity of fats. These include butylated hydroxy anisole (BHA), butylated hydroxy toluene (BHT), and tocopherol. To prevent mold and bacterial growth, producers use either sucrose, propylene glycol, sorbic acid, or potassium and calcium sorbates.

The Manufacturing Process

Except for the ingredients, the general manufacturing process for pet food is similar to that for processed food for humans. Meat products used in pet foods must first be rendered, or processed, to separate the water, fat, and protein components, including soft offals (viscera) and hard offals (e.g. bones and hoofs). Generally, meat is rendered by specialist companies and shipped to pet food manufacturers. The meat products intended for canned food must be delivered fresh and used within three days. Frozen meat products may be used for dry foods.

The manufacturing process entails grinding and cooking the flesh and flesh byproducts. Next, the meat is mixed with the other ingredients, and if the recipe requires, the mixture is shaped into the appropriate forms. The finished product is filled into containers and shipped to distributors.

Innovations in pet food processing and packaging have led to improved quality with a longer shelf life. Canned dog foods that are vacuum packed have a shelf life of three to five years and are very stable with little or no loss in nutritional value. Dry dog food, on the other hand, has a shelf life of only 10 to 12 months and requires the addition of preservatives, though some manufacturers are using natural preservatives such as vitamins E and C.

Rendering the meat
  • Generally, rendering is performed by meat processors. Rendering entails rupturing fat cells, either by heat or enzymatic- and solvent-extraction, and then drying the residue.
Grinding and pre-cooking the meat
  • The meat products are coarsely ground to the desired texture.
  • To facilitate further processing, the ground meat is cooked in a continuous cooker with live steam at the appropriate temperature.
  • The flesh products are reground after initial cooking to produce a more uniform consistency. For semi-moist or chunky foods, the batches are deliberately cooked unevenly to create the desired chunky texture.
Blending and shaping
  • The meat mixture is blended with other ingredients such as cereal grains, vitamins, and minerals.
  • Dry and semi-moist foods are usually heated so the mixture will partially dextrinize, or thicken, the starch. To achieve the marbled-look of real meat, the meat mixture may be cooked unevenly and half of the batch colored red and the other white. Semimoist foods must be stabilized to retain the proper amount of moisture in the dry and semi-moist parts of the food.
  • Dry and semi-moist foods may be extruded under high pressure through a device with orificed plates to obtain the shape and size of the specific product, for instance, the form of biscuits, kibbles, meat-balls, patties, pellets, or slices. An alternative to extrusion is to gelatinize and expand the mixture. For marbled meat, the mixture of red and white meat is extruded together and broken into chunks.
Packaging and labeling
  • Measured amounts of the product are packaged into appropriate containers. Dry foods are poured into pre-printed containers. Moist canned foods are vacuum sealed to reduce the oxygen content and prevent spoilage of fats in the food.
Sterilizing
  • Cans of pet food are sterilized by passing them through a retort, or heating chamber. The retort may be either a batch or continuous hydrostatic type. The cans are heated to about 250°F (121°C) for 80 minutes, though the cooking temperatures and times depend on the contents, steam pressure, and can size.
  • The cans are quickly cooled to about 100°FO (38°C). Next, the cans are dried and labeled.
  • The containers are packaged into corrugated cardboard boxes or shrink-wrapped with plastic in corrugated cardboard trays. The pet food is ready fot shipping to distributors.

Contents

Less expensive dog foods generally include less meat, and more meat by-products and grain "fillers". The most expensive dogs foods may be made of ingredients suitable for human consumption, organic products, or free-range meats.

Special varieties

There are dog foods specially formulated for dogs allergic to wheat, corn, and/or chicken. These foods usually contain lamb or fish meat. Some dog foods are designed for dogs with maladies such as urinary tract infections, and some foods are tailored to the dietary needs of especially young or old dogs. There also exist vegetarian dog foods marketed to owners who do not wish for their dogs to consume meat products.

Holistic food

There are also varietes of dog food available for those who wish their dogs to eat human grade food. The holistic dog food industry is a growing business as scandals arise about rendering plants, toxins and poor nutritional value.

Commercial Food "Guidelines"

  • 95%: If the product says “Salmon Cat Food” or “Beef Dog Food,” 95% of the product must be the named ingredients. A product with a combination label, such as “Beef and Liver for Dogs,” must contain 95% beef and liver, and there must be more beef than liver, since beef is named first.
  • 25% or “Dinner” Rule: Ingredients named on the label must comprise at least 25% of the product but less than 95%, when there is a qualifying “descriptor” term like “dinner,” “entree,” “formula,” “platter,” “nuggets,” etc. In “Beef Dinner for Dogs,” beef may or may not be the primary ingredient. If two ingredients are named (“Beef and Turkey Dinner for Dogs”), the two ingredients must total 25%, there must be more of the first ingredient (beef) than the second (turkey), and there must be at least 3% of the lesser ingredient.
  • 3% or “With”: A product may be labeled “Cat Food with Salmon” if it contains at least 3% of the named ingredient.
  • “Flavour”: A food may be labeled “Turkey Flavor Cat Food” even if the food does not contain such ingredients, as long as there is a “sufficiently detectable” amount of flavor. This may be derived from meals, by-products, or “digests” of various parts from the animal species indicated on the label.
  • Avoid food with terms such as ‘meat meal’ and ‘meat by-products’
  • Check the expiration date to ensure freshness.
  • When you open a bag of dry food, give it a sniff — if there is any rancid odor at all, return it immediately for an exchange or refund.
  • Store dry pet food in a sealed non-porous container (a large popcorn tin is ideal) in a cool, dry place.
  • Canned food is best removed from the can and refrigerated in a glass or ceramic container.
  • Fresh food can be supplied as part of the diet, along with commercial foods for a complete diet.

Homemade diets

There are many different recommendations on what diet is best for dogs. Some people argue that commercial dog foods contain additives or poor-quality meat or ingredients dogs should not ingest, or that certain commercial foods are not nutritionally sufficient for their dogs. Different homemade diets are recommended by various experts, from "natural" diets consisting primarily of raw meat, to vegetarian diets consisting only of nutritionally balanced vegetarian ingredients, to mixtures consisting of ingredients such as brown rice, brown pasta, meats, eggs, and vegetables.

Most dogs willingly eat vegetables and many kinds of fruit, although garlic, onions, grapes, avocados, and raisins are toxic to dogs.

Raw food

There is a growing interest in raw food for dogs. Concerned pet owners are now turning to freeze-dried food or the Bones and Raw Food (BARF) diet.

  
Sources:
Wikipedia
"Pet Food." How Products are Made. Ed. Stacey L. Blachford. Thomson Gale, 2002.
eNotes.com. 2006. 20 Oct, 2006