Protection of Agriculture and the Food Supply

In his October 2001 executive order establishing the Office of Homeland Security, President Bush added agriculture and the food industries to the list of critical infrastructure sectors requiring protection, and acknowledged that the agriculture sector and the food supply are vulnerable to bioterrorists. The Secretaries of both Agriculture and Health and Human Services have publicly recognized that the US food supply is susceptible to deliberate contamination. Attacks could be directed at livestock, crops, and food products.

Our agriculture and food sectors have features making them vulnerable; our livestock industry is highly concentrated, as is the centralized nature of our food processing industry, which suggests that infectious pathogens and chemicals could be intentionally added at a number of points along the farm-to-table continuum. Even the threat of an attack could adversely affect the public is confidence in the safety of the food supply and destabilize the export market, as recently occurred with a dozen countries refusing to import our beef because of the widely reported finding of a single "mad" cow in the State of Washington.

An excellent case in point is the 2001 foot-i n-month epidemic that swept through England. On February 20, 2001, the presence of foot-and-month disease was confirmed in Essex, England. The virus, a single-stranded RNA rhinovirus, spread rapidly, eventually resulting in over 4 million cattle being slaughtered to control its further spread.

Terrorists seeking ways to harm the United States, could deliberately introduce foreign animal diseases into the country. Accepting that idea, the USDA recently calculated that a foot-and-mouth outbreak could spread to 25 states in as little as 5 days. A simulation by the National Defense University in June 2002 predicted that a foot-and- mouth outbreak could spread to more than one-third of the nation's cattle herds [39]. When it does, vesicles appear in the mouth and on the upper lip, on the coronary band of the foot, and on the mammary glands and areas of fine skin. Foot-and-mouth disease (FMD) is a visual misery, and can ' t be missed. These vesicles burst, leaving painful, red erosions. Secondary bacterial infections of the open vesicles can also occur in the mouth and on lips. For a terrorist, the fact of virus elimination via all secretions and excretions offers added reward. Large quantities of virus are eliminated in saliva, which is responsible for both environmental and airborne contamination. Virus can then be spread widely by drinking water, breathing in aerosols, and eating contaminated food. The appearance of FMD on a farm signals turmoil. Farmers know that they and all other people on the farm along with their dogs and cats can become transmitting sources (vectors), carrying the virus on boots, wheelbarrows, and truck tires. If infected animals aren' t spotted quickly and culled from the herd, spread and ruin are inevitable [40]. In Britain, the epidemic caused suicides among farmers who saw their livelihoods go up in smoke. Add to that the fear of air and water pollution from animal carcass disposal. And as the epidemic occurred in August, it totally wiped out tourism as the tens of thousands of tourists who had planned to arrive canceled their reservations. FMD followed hard on "mad cow" disease, which the public worldwide had been led to believe was both a human and animal disease, that humans could get from animals, and that eating the famous English beef was unsafe. That was more than enough; people headed in other directions. Bioterrorism has many faces—all ugly.

The U.S. General Accounting Office, looking at measures for preventing FAD and "mad cow" from entering the United States, found that because of the sheer magnitude of international passengers and cargo entering the country every day, the available inspection resources are simply unable to ensure preventing entrance. They simply can not inspect everything. They also found that

FMD can be carried on the shoes of international passengers who visited farms, and on packages they carry. The virus can be transmitted in international mail and in garbage from international ships and airlines. The FMD virus is a hardy bit of protein that can survive for considerable periods in diverse environments. It can remain viable in salted bacon for 3 months, and in air-dried hides and skins for 6 weeks. If a person steps in infected manure, the virus can endure for 2 months in summer and 3 in winter. Such a delivery spectrum can be deliberate or benign. Mad cow disease, benign spongiform encephalitis (BSE), has been more sound than fury, and does not lend itself to terrorism. But could an animal be slipped in among a herd coming into the country, to be discovered later? Indeed it could, and that "discovery" could trigger a ruinous economic boycott. Figure 3.6, illustratres the layers of governmental involvement that provides substantial and reassuring protection against such a possibility.

Food and food processing is generally considered the midpoint of the farm-to-table continuum, and it is generally agreed that terrorists could use food as vehicles for introducing bioagents into the food supply. A food poisoning epidemic in 1994 that sickened 224,000, people can serve as a model and cautionary tale, even though it was an inadvertent accident. The fact is, it highlights the vulnerability of our open society.

Figure 3.6. Federal government agencies involved in bovine spongiform encephalopathy (BSE) oversight. (Figure adapted from General Accountability Office, GAQ-04-588T.)

Salmonella enterididis, a known food poisoning organism, was the microbe that produced the largest salmonellosis outbreak and the largest food poisoning outbreak in US history—and, of all things, it did so in America's favorite food, ice cream. The centralized nature of our nation's food distribution networks lends itself to endangerment of huge numbers of consumers. Commercial ice cream producers use only pasteurized milk, and pasteurization kills all salmonellae. It ' s the homemade ice cream, often made with unpasteurized milk, that allows salmonella to grow and produce its toxin in ice cream. How, then, could ice cream become the vehicle of the gastroenteritis that laid low so many thousands of ice cream lovers.?

Tanker trailers hauling thousands of gallons of ice cream made from base premix had hauled nonpasteurized eggs to processing plants before taking on the ice cream mix. That would have been okay had the tanker drivers not broken established work rules, which required tankers hauling unpasteurized liquid eggs to be thoroughly washed and sanitized before loading ice cream premix. The salmonella-containing liquid eggs contaminated the premix, which was not repasteurized after transportation, and 224,000 vanilla ice cream devotees became surprised and accelerated half-steppers [41] . Could this happen again? Yes. Deliberately? Again, yes.

The way to prevent it is to take control away from drivers and maintenance crews. Either liquid eggs cannot be delivered in trucks that also carry premix, or trucks that have dischared a load of liquid eggs must be automatically sealed when their contents are emptied and should not be opened until they are in a cleaning station, or some such unit. But to evade the system shouldn't be difficult. Again, it's the human equation. A bribe might be all it takes to avert eyes as a culture of tularemia or plague is dropped into a tanker. Yes, it surely could happen again, and it could sicken and kill thousands. This is exactly what the two Stanford University professors had in mind with their idea of botulinum toxin in milk.

Unfortunately Congress has not yet moved to give the FDA authority to require food processors to take safety measures to improve security against deliberate attempts at compromising the country's food supply.

Food crops—especially the cereal grains, wheat, barley, and rye, along with the most widely eaten staples, corn, rice and potatoes—are recognized targets of terrorism. Disruption of basic food supplies has caused famine and can cripple a country. Characteristically, fungal diseases of wheat and rice, and other cereals, are spread by fungal spores that can withstand environmental stresses and distruction. These spores infect the aerial parts of plants, causing diseases that have the capacity to spread rapidly, attaining epidemic (epiphytic) proportions during a single growing season. For a notable, and unforgettable, natural fungal devastation of a crop, we need only glance backward to the Irish potato famine of 1845-1848, a famine of unimaginable proportions, the result of infection of the potato crop by Phytophthora infestans, which continues on current short lists of potential anticrop weapons, and has been given the codename, "LO."

Intense potato cultivation in Ireland had accommodated a remarkable 70% population increase between 1745 and 1841. By 1840, potatoes were the sole food of 30% of the people, and essential to another 30%. Potatoes were eaten in place of bread, and the two main meals of a laborer- s day consisted of potatoes.

Potato Late Blight first occurred in autumn 1845. In August 1845, John Lindley, the newly appointed professor of botany at the University of London, and editor of the Gardeners Chronicle and Horticultural Gazette, wrote: "A fearful malady has broken out among the potato crop. On all sides we hear of destruction. In Belgium the fields are said to be completely desolate. There is hardly a sound sample in Convent Garden market. . . .As for cure for this distemper, there is none." He continued: "We are visited by a great calamity which we must bear." The desperate nature of the devastation was announced on September 13: "We stop the press with very great regret to announce that the potato Murrain has unequivocally declared itself in Ireland. The crops about Dublin are suddenly perishing. . . . Where will Ireland be in the event of a universal potato rot?" [42] . The rot was all-encompassing. Starvation was widespread. A wholesale exodus followed in which hundreds of thousands of people fled the country. Between 1845 and 1851, the population of Ireland decreased by more than 2%. A mold, a fungus, changed the course of Irish history.

Molds, rusts, and smuts are fungi. Although they often look like plants, they aren't. Plants are green, and contain chlorophyll, which does not occur in fungi. Consequently fungi can not produce their own food and must obtain nourishment by digesting plants, living or dead. Fungi secrete digestive enzymes into the plant they parasitize, and absorb their nutrients. Fungi can destroy crops by causing diseases such as leaf spot, blights, smuts, rusts, and blasts. Trees can also be victimized. Dutch Elm disease, the worst such outbreak in the United States in recent decades, was the work of Ceratocystis ulmi.

Anticrop agents considered well qualified include stem rust of wheat, the result of infection with Puccinia graminis. codenamed TX. Puccinia is the largest genus of rust fungi, and P. graminis is the most destructive fungus of all cereal grains. Black stem rust of cereals is a pathetic sight. Pustules of spores erupt through leaf surfaces looking for all the world like smallpox of plants. As the plant matures, the pustules blacken, then break open, releasing masses of brown spores that are now freee to infect surrounding plants.

Ustilago, the principal genus of the smut fungi, includes U. maydis on corn and U. nuda on wheat and barley. The ears of barley infected with Ustilago look as if dusted with soot; hence they are called "smut" fungi. Interestingly enough, wheat cover smut, a strain with crop-destroying potential, was evaluated for use as a weapon. Research done at Salmon Pak, outside of Baghdad, Iraq, "in 1985, demonstrated that wheat cover smut spores sprayed over immature wheat plants would be lethal to crops." In his discussion of Iraq's biological weapons, Raymond A. Zilinskas informs us that "In 1988, young wheat plants growing in large fields near the town of Mosul were infected with this agent: the infected wheat subsequently was harvested and moved to Fudaliyah for storage. The Iraqi's claim that no attempt was made to recover fungus from the harvest and that the infected crop was destroyed in 1990." He goes on to say that" the investigation of wheat smut implies that Iraqi leaders know that biological weapons were more than anti-person weapons; they could also be used against crops as part of economic warfare" [43].

Magnaporthe grisea, codenamed L4, the causal organism of rice blast and the most destructive worldwide, is also on the short list of potential anticrop agents. Clearly these fungi could easily be used to adversely affect the world's must economically and socially significant food and cash crops: cereals, potatoes, and rice, the world's major food crops. Attacks on cereals could seriously affect bread production, and coffee berry disease due to Colleotrihium cof-feanaum, which seriously reduces yields and kills coffee plants could surely disrupt supplies of coffee beans. With over 13,000 fungal species, the possibilities appear endless, and that a given crop species such as wheat can be destroyed by over 200 different diseases worldwide, indicates that terrorists have unlimited choices at their disposal.

The potential of dual-use capabilities of weed and pest control chemicals is also worth considering. The fact these could go either way poses yet another serious threat that they could be used for malign purposes. The immensity of the security needs faced by leaders at all levels of government can be daunting.

In the United States, use of biopesticdes and biocontrol agents is increasing, replacing chemical pesticides, which can be a double-edged sword. Bacillus thuringiensis produces a protein toxic to lepidoptera (caterpillars), diptera (flies), and coleoptera (weevils and beetles). Freely available scientific literature provides detailed descriptions of fermentation techniques used in the rapid and large-scale production of a range of organisms, or their toxic products. If that were not information enough, genetic manipulation of organisms to enhance their effectiveness is available to anyone with a computer and Internet connection, which means just about anyone.

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