Bio Threats

   
Bio threats may be terrorist-initiated or naturally occurring. Besides the value of supporting national security relative to weaponized bio-related threats from terrorists, bio-related sensing can also protect the food chain (production, storage, transport) and the U.S. agriculture industry.
NevadaNano has been able to detect and differentiate the presence of several biological agents and other vapors that would normally occur in the same environment.  In this work, we demonstrated identification of vapors produced by different strains of E. coli as well as those produced by Serratia marcescens, an analog for the Category A bacterial threat, Yersinia pestis (plague).
This ability to detect airborne vapors from bio threats and other organisms provides a simple, robust detection method that fits well with any sensor system focused on air sampling, especially where it is also advantageous to also detect explosive and chemical threats. The odor signature approach for bio detection has been previously demonstrated with other electronic nose technology for the detection and discrimination of bacteria, and is likely to be the most robust and reliable method for field use due to its relative ease of implementation.
All living organisms give off unique mixtures of exhaled gases as part of their metabolism. These distinct metabolite signatures can include unburned hydrocarbons, alcohols, ammonia, oxygen, carbon dioxide, short-chain fatty acids, aldehydes, and other breakdown products of amino acids. These characteristic “odors” can be detected and differentiated using pattern recognition techniques in order to identify bacterial strains. This approach has been demonstrated for diagnosing bacterial infections by sampling urine vapor, to detect pulmonary infections in patients’ breath, to predict bacterial type and culture growth phase, to classify grains, and to detect and identify a range of microorganisms. A representative study of the volatile components given off by selected microorganisms is provided in Table 1. This work supports the concept of vapor based detection for some bio threats.
Table 1: Volatile chemical compounds emanating from select bacteria and other microorganisms.
Source: T.D. Gibson, et al., “Detection and simultaneous identification of microorganisms from headspace samples using an electronic nose.”
 Ag Industry and Food Chain Bio Threats
   
Threats to the US agriculture industry can be terrorist initiated, but are usually naturally occurring — often caused by accidents or careless practices somewhere in the food chain. Agriculture-related threats can be harmful to humans or, in some cases, simply harmful to businesses involved in the food chain. Either way the industry suffers when an outbreak occurs.  Prime examples of this were the E. coli outbreak that occurred in the United States in February 2008 related to the beef industry, the Salmonella outbreak in the U.S. in May 2008 related to produce, in particular peppers and tomatoes, and the deadly Salmonella outbreak of January 2009.
The source of the May 2008 Salmonella outbreak was not easily identified. In Florida alone, at least $40 million worth of tomatoes were destroyed. As Florida Agriculture Commissioner Charles Bronson told the Oversight and Investigations Subcommittee of the House Committee on Energy and Commerce: ”But I can tell you we never anticipate that our business will be destroyed by an action of the federal government…Millions of dollars lost and yet there is still not a shred of evidence suggesting that Florida-grown tomatoes were the source of this outbreak.” Investigation later determined that jalapeño peppers were the most likely cause. Most recently, a Salmonella outbreak in the US attributed to peanut butter claimed 9 dead by February 14, 2009 with over 500 ill with the disease.
The beef recall of February 2008 due to E. coli was the largest ever in the history of U.S. agriculture, with the total amount of recalled meat topping 143 million pounds. Although there was no official estimate of the total value of destroyed beef, an official of the Grocery Manufacturers of America confirmed it ran into hundreds of millions of dollars. In addition to the value lost in the particular food item, revenue is also lost downstream for products that use a suspect agriculture good as an ingredient.
Sensors for these and other bio-pathogens can be placed at numerous levels of the food chain, starting with the harvesting/gathering site and including the processing and transport stage in order to protect the U.S. agriculture industry as well as consumers.  Recorded outbreaks to date have been attributed to accidents or careless business practices. However, the potential disruption and damage that a carefully planned, terrorist-initiated outbreak would inflict on the food chain and US agriculture industry should not be underestimated.  NevadaNano’s sensor technology has shown the ability to detect E. coli and other pathogens, and shows great potential for this application.