The consumer lore that probably raises the most controversy and elicits the most emotive response is that pet food provides a market for slaughterhouse offal unfit for human consumption. Only true vegetarians can take exception; the rest of us want the animal slaughtered so we can consume animal protein.

Offal is used as a source of animal protein as cats and dogs need animal protein in their daily diet. Cats in fact, are true carnivores and depend on animal protein to supply an integral part of their protein needs.

These animals, from which the so-called waste products are derived, are all originally led to slaughter to supply animal protein (meat) to man! All the soft tissue of animals is made of animal protein or fat and mostly the tissue is a mixture of both. But protein is not only supplied from animal ‘waste'. All vegetable material included in pet food contains varying levels of protein derived from vegetable origin, as well. When designing a pet food, nutritionists balance animal and vegetable proteins to match the pet's needs as closely as possible.

Thomas Meyer in an article in PETS International Magazine (May 2004) estimates that humans consume 54% of cows and 62% of pigs, sent to slaughterhouses. Lamb falls between these two levels. Cowhides are included in this, as these are used for seat covers, shoes, car seats, etc. for humans. Skins and long bones, including the head skeleton, are parts of these animals NOT normally consumed by man and also NOT consumed as waste by pets.

What “waste” does man NOT consume?

Travel to Brazil and visit a Brazilian Chuscarria and you could be offered a skewer consisting of pig's udder or mammary gland as an appetiser. Cross the Andes Mountains into Chile and visit a Cattleman's Restaurant and the Chef may offer you as a special starter, bullocks testes on toast. The British made Tripe ‘n Onions famous. Tripe is nothing other than the feathered wall lining of a cow or lambs stomach. Other cultures will offer you spleen as sweet meats, and still others will regard eyes or brains as delicacies. Ox tail, liver, kidneys (as in steak & kidney pie), heart, diaphragms, brisket and tongues are all eaten to various degrees, while lungs may be used in polony.

So what becomes “waste” or by-product, unfit for human consumption, that is turned into meat protein meals for pet food, animal feed and other products, is very different between countries and cultures.

As with by-product surplus discussed in an earlier article, this is best explained by quoting from Animal By-Products in Pet Food PETS International Magazine, May 2004, by Thomas Meyer, former Secretary General of the European Pet Food Industry Federation (FEDIAF):

“Back in 1990, the European legislator regulated which parts of an animal may be used for pet food production. The terms used sent shivers down the spine: ‘animal waste' and low-risk material'. People looking for a meal rich in iron and vitamins were quite happy to eat beef livers, but the same liver, as surplus from human food chain, suddenly became “waste” with a definite connotation of ‘risky'. But already then, the European pet food industry had its voluntary code to use only animal protein derived from slaughtered animals passed as fit for human consumption.”

Meat by-products, or meat and bone meals, which are used for pet food, are produced by rendering (i.e. cooking and drying) the surplus soft tissue not used for human consumption. This composition may differ according to country and cultural influences and relative demand for various animal body parts.

Naturally there are other by-product materials, such as bruised meat. A bruise is where, due to physical damage, blood has been released into the muscle. Man will not eat this as it is unsightly (although many regard blood sausages as a delicacy) and the concentration of blood makes it difficult to keep the meat from spoiling without freezing or immediately cooking by rendering. Rendering into by-product meals allows for ease of handling and room temperature storage, alleviating costly refrigeration needs, before inclusion into a pet food. Of course not all renderers play strictly to the rules, but it is the duty of the pet food manufacturer to know his supplier and not to buy from those who include inappropriate materials into their meals. The difference is once again indicated by the price paid for the meat meals or by-products, which carry over into higher prices for the pet food in the store.

Only small bones end up in meat and bone meal, which is cooked and milled to small (imperceptible in the best quality by-products) grain-sized particles. This bone is a natural source of calcium, phosphorus and many trace minerals in the pet food when the by-product is included.

As with the European Union, South Africa has rules on rendering, registration requirements and controls. Thomas Meyer explains that the EU has a 100-page legal-technical regulatory document to manage the quality of 16-million tonnes of animal by-product per annum included in pet foods. We still need to improve this in South Africa.

In the UK, primary industry pays for the removal and rendering of these by-products. As visitors to their shores, we know the high cost of meat compared to local meat in South Africa. In South Africa we have a large demand for specific offal types that are regarded as by-product offal in the UK, so this already changes by-product composition in this country. In South Africa the return on disposal of these by-products to the populace and thereafter largely to the pet food industry, keeps food costs down and facilitates material usage at primary consumer level. The materials are valuable animal protein sources for pet food and there is no question with regard to the nourishment they provide – although it is rejected by humans, it is still potentially consumable by people.

Meat and poultry by-products contain high fat levels and fats must be protected against degradation by oxygen (oxidation) by using anti-oxidants. Good quality meat by-products will also be protected against potential mould growth to extend their shelf life at room temperature. BUT this has nothing to do with added animal fats, restaurant grease or other oils, which also have NOTHING to do with meat by-products.

By-products are produced through a cooking process to preserve them and kill off any bacteria present. Veterinary Health Services check all rendering plants where these by-products are cooked and dried, for microbiological activity. The belief that pet food manufacturers do not test their products for endotoxins is clearly incorrect. Manufacturers and legislators set standards for suppliers of by-products from primary industry to follow.

The quality of meat and poultry by-products is reflected in the price of dog food. The term “by-products” is not a dirty word for waste, but a description of nutritious materials that humans choose not to eat, and instead can become valuable nutrition for pets and other animals.

Visit www. petwise.co.za and read more about pet nutrition and pet care. You can also learn about reliable manufacturers in the pet food industry, who are also members of the PFI Association.