How Now Mad Cow

Traditionally, MBM was prepared by a rendering process involving steam treatment and hydrocarbon extraction.

a protein-rich fraction called 'greaves' containing about 1% fat from which MBM was produced
a fat-rich fraction called 'tallow' which was put to a variety of industrial uses.

In the late 1970s, the price of tallow fell and the use of expensive hydrocarbons in the rendering process was discontinued, producing an MBM product containing about 14% fat in which the infectious material may not have been inactivated. As a result, a ban on the use of ruminant protein in cattle feed was introduced in July 1988:

In November 1989, human consumption of specified bovine offals (SBO) thought most likely to transmit the infection (brain, spleen, thymus, tonsil and gut) was prohibited. A similar ban on consumption of offals from sheep, goats and deer was finally announced in July 1996 to counter concerns about transmission of BSE to sheep. The available evidence suggests that milk and dairy products do not contain detectable amounts of the infectious agent.

The total number of BSE cases continued to rise, as would be expected from the long incubation period of the disease, and the peak incidence was reached in the last quarter of 1992, since when the number of new cases has started to fall.

Traditionally, MBM was prepared by a rendering process involving steam treatment and hydrocarbon extraction.

© AJC 1997.