New bacteria sensor fights disease

The invention is likely to be popular with manufacturers and consumers alike, as reports suggest that diseases such as E. coli and Salmonella are becoming more and more commonplace. Researchers from the University of South Carolina claim to have developed a polymer material that changes colour in the presence of biogenic amines, compounds produced by the bacterial decay of food proteins. "The conjugated polymer generates a multidimensional response capable of identifying and differentiating between 22 structurally similar and biologically relevant amines with 97 per cent accuracy,"​ they said in the journal Organic Letters​. In laboratory tests, the polymer was more accurate than the traditional 'electronic nose', which identifies odours from its specific components and chemical make-up. Unlike previous identification methods, the new polymer can detect amines in water, according to the researchers. The deterioration of biogenic amines has been associated with rapid cell growth, associated with a number of health problems including food poisoning, bacterial infection and even cancer, the report states. The technique is dual-approach, with an array of wavelengths used to recognise the compounds, and then a ratiometric approach employed to quantify the amines. "We are currently investigating these approaches for the detection of biogenic amines in fish and other foods as a means to determine freshness and quality,"​ concluded the researchers. Food borne diseases such as Salmonella and E. Coli are sometimes fatal, and incidences are on the rise, according to the Center for Disease Control and Prevention (CDC). In the US, an estimated 76 million cases of foodborne illnesses occur each year, causing about 325,000 hospitalizations and 5,000 deaths. The CDC identified 17,252 laboratory-confirmed cases of food poisoning in 2006, including 6,655 cases of salmonella and 590 cases of E.coli O157. In 2005, 16,614 cases were identified, rising from 15,806 in 2004. In the EU, there were 192,703 reported cases of salmonella across the 25 member states in 2004. Food safety scares also have a long lasting impact on purchasing decisions, with Harris Interactive research suggesting that 15 percent of consumers stop eating a product entirely after a food safety incident. Source: Organic Letters​ Published on-line ahead of print: ASAP Article doi: 10.1021/ol071065a S1523-7060(07)01065-6 "A Food Freshness Sensor Using the Multistate Response from Analyte-Induced Aggregation of a Cross-Reactive Poly(thiophene)" ​Authors: M.S. Maynor, T.L. Nelson, C.O'Sullivan, and J.J. Lavigne