Fighting Mad Cow Disease: Prion Remediation via Composting

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With current methods, prions keep getting back into the food chain. That means more deaths due to mad cow disease. Is composting the answer? Image by Decoded Science, all rights reserved

With current methods, prions keep getting back into the food chain. That means more deaths due to mad cow disease. Is composting the answer? Image by Decoded Science, all rights reserved

Mad-Cow Disease comes as the result of ingesting prions. The current methods of disposal are not 100 percent fool-proof, which means that the prions go right back into the food chain, spreading infection. Now, however, we have word from Canadian researchers in the journal Environmental Science & Technology that the means to readily bio-degrade the Mad Cow agent on a large scale is close at hand.

These researchers report 90 percent ‘kill-off’ for tissue infected with the Mad Cow agent and a 99 percent ‘kill-off’ for tissue infected with a similar agent that is responsible for Creutzfeldt-Jacob syndrome.

What Is Mad Cow Disease?

Mad Cow syndrome became an issue in the 1990s when individuals in Europe and in the US became ill with a brain wasting disease; the illness was contracted after eating beef infected with the agent—a protein. The affected tissue is contagious; the disease spread from animal to human when cows were fed tissue of previously infected animal protein.

Presently, there have been 23 confirmed deaths due to Mad Cow syndrome in North America and outbreak has resulted in $ 11 billion dollars in cattle loss, as well.

Prions and Mad Cow Disease

The term prion came to the forefront of public perception in the early 1990s. What many in the mainstream media and science found it hard to believe, at the time, was how a prion could alter human and animal behavior. Prions accomplish this by irreversibly changing brain tissue. Prions act like viruses, co-opting brain tissue and in effect turning healthy individuals and animals into weak shells of their former selves. However, the pathogen did not possess a discernible ‘cell structure.’ It seemed as if it were acting like alone.

The best thinking presently seems to indicate that prions tend to behave like dominoes; once set in motion, there is very little one can do to stop the process. The affected protein adopts a configuration, or chemical structure, that differs from normal physiological functioning. Adding to the mystery is evidence that indicates that there may be more than one agent (or chemical structure) that infects the body at these times.

A representative structure of a partial protein resembles the following structure:

Partial skeletal structure of a Prion.

Partial skeletal structure of a Prion. Courtesy of National Institutes of Health

Getting Rid of Prions

When animals have prions, it’s critical to properly dispose of the corpses in order to avoid spreading the outbreak. Researchers discovered a method to bio-degrade the agent in the early 2000s.

The researchers successfully subjected infected tissue to enzymes that ‘digested’ the prions – but this method had not been tested on a large scale. At the time, three separate research groups found that various bacteria and fungi could digest the infected tissue under highly alkaline conditions.

The Canadian workers utilized a composting methodology to destroy the affected protein material, subjecting the prion material to an aerobic cattle manure compost that contained the following Streptomyces, Thermus, Bacillus, and Tritirachium genera of bacteria for up to 3 months. The results were good enough to warrant further investigation.

Previous methods involved incineration or rendering followed by burial. The methodologies have proved to be economically hard and not fool-proof.

While the incineration method may seem like a good idea, it is not completely effective nor is it economically sound. Burning the tainted meat involves a two-stage incineration that is followed by an alkaline disinfectant and autoclave. This methodology is effective only in high volume. It has proved to be non-feasible to accomplish it on a daily basis.

Rendering and burial does not always work either, due to the hardiness of the prion particle – we find ‘non-rendered’ prion material in the soil following the burial; prions have entered the food chain through the process of rendering and burial.

Fighting Mad Cow Disease

Since the discovery of prions three decades ago, we have not found a method of removing the tainted meat from the food chain that works effectively. Our successes have come at a cost-a cost too  hard to bear for those unlucky enough to have ingested the protein. A cost that some have deemed too high because they found it too hard to accept the notion that agricultural standards need to evolve with the needs of society. However, new research into composting may hold the key to solving this years-old puzzle.

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