Rothsay Rendering

Have you ever wondered where the expired meat products from butcher shops, grocery stores and meat delis go?

The inedible fat and protein animal by-products that are produced from abattoirs, food processing plants, grocery stores, and butcher shops are recycled through a process called rendering.

Sometimes referred to as the "invisible industry" because its existence is relatively unknown, rendering is an essential service that is a shining example of environmental sustainability. Because only about 50% of a cow, 60% of a pig, 72% of a chicken, and 78% of a turkey actually end up in the supermarket, a safe method of by-product disposal is vital for disease prevention in both animals and humans.


For centuries the rendering industry has made a unique business of reprocessing discarded animal by-products into goods used in agriculture and for everyday life.

Historically, rendering consisted mainly of using animal lard to make soap and candles. Today, renderers convert these materials into valuable commodities that are used to manufacture a variety of products, ranging from feed supplements to fuel to cosmetics.

Why Render?

Rendering provides a means of efficient disposal of animal by-products and conservation of other resources. If rendering were not used to dispose of these by-products they would most likely be sent to a landfill or incinerated.

Incineration: This option is safe, but very energy intensive if the material is not first rendered, and therefore comes at a steep price. It is estimated that this method of disposal would cost the food industry $2 billion annually if used in Canada.

Landfill: This is a more cost-efficient method but also impracticable because of the tremendous volume of animal by-products. It is estimated that if the 27 billion kilograms (or 59 billion pounds) of North American animal by-products were disposed of using this method, it would fill all existing landfills within four years. In addition to capacity restraints, landfilling poses serious heath and environmental threats because of the high risk of ground water pollution, spread of communicable disease, vermin infestation, and odours associated with decomposition.

For more information on the process of rendering, please visit the National Renderer’s Association (NRA) website at

The Rendering Process

The Process

Animal by-products are collected from butcher shops, restaurants, supermarkets, farmers, abattoirs and other operations to be processed under high temperatures in order to remove water and to eliminate bacteria.

Modern rendering plants use automated continuous systems which breaks down the material to its base elements; protein, minerals, water and fat.

The resulting finished products are then either returned to the agricultural chain in the form of feed supplements or used in industrial and consumer products.