Collagen is the main protein of connective tissue in animals. It is found exclusively in metazoa, including sponges, and is the most abundant protein in mammals, making up approximately 25% to 35% of the bodies protein content. As a major component of endomysium, collagen comprises between one and two percent of muscle tissue, and accounts for six percent of the weight of muscles. Collagen is also a major component of cartilage, ligaments, tendons, bone and skin. Its natural tensile strength is evident in the strength and elasticity of skin and blood vessels. It also contributes to vision and is located in the cornea and lens of the eye in crystalline form. It is widely used in the medical profession, being an essential component of many cosmetic, dental, orthopaedic and burn surgery procedures.
However, there have been concerns over the use of bovine collagen since the outbreak of Transmissible Spongiform Encephalopathies (TSE’s), of which BSE gained the widest media attention. Bovine spongiform encephalopathy (BSE), commonly known as mad-cow disease (MCD) is a fatal, neurodegenerative disease in cattle that causes a spongy degeneration in the brain and spinal cord. BSE has a long incubation period, about 4 years, usually affecting adult cattle at a peak age onset of four to five years, all breeds being equally susceptible. In the United Kingdom, the country worst affected, more than 179,000 cattle have been infected and 4.4 million slaughtered during the eradication programme.
It is believed by most scientists that the disease may be transmitted to human beings who eat the brain or spinal cord of infected carcasses. (note 3). In humans, it is known as new variant Creutzfeldt-Jakob disease, and by February 2009, it had killed 164 people in Britain, and 42 elsewhere with the number expected to rise because of the disease’s long incubation period. (note 4). Between 460,000 and 482,000 BSE-infected animals had entered the human food chain before controls on high-risk offal were introduced in 1989.
A British inquiry into BSE concluded that the epidemic was caused by cattle, which are normally herbivores, being fed the remains of other cattle in the form of meat and bone meal, which caused the infectious agent to spread. The origin of the disease itself remains unknown. The infectious agent is distinctive for the high temperatures at which it remains viable; this contributed to the spread of the disease in Britain, which had reduced the temperatures used during its rendering process. Another contributory factor was the feeding of infected protein supplements to very young calves.
Collagen products prepared from bovine materials may carry the risk of transmission of animal BSE agents. Users of collagen in pharmaceutical, cosmetic and surgical industries must ensure that the bovine materials are free of any TSE’s and materials from other animal species in which TSEs naturally occur. To ensure this occurs, bovine materials should be obtained from countries which have a surveillance system for BSE in place and which report zero or cases of BSE.
According to a European Commission study undertaken by the European Food Safety Authority to assess the risk of finding BSE in a number of countries, New Zealand is among one of the few countries that do not have TSE’s, with not one case of BSE ever being diagnosed in either country. Experimentation in the UK and EU has used New Zealand cattle as guaranteed BSE-free controls. As a result, New Zealand has developed a reputation for providing high quality BSE-free bovine collagen to the international marketplace.