Food poisoning caused by pathogenic bacteria continues to be a major concern and most of the instances are traceable back to food producers. The number one organism of concern, especially with refrigerated food, is Listeria monocytogenes; second comes nontyphoidal Salmonella species.)
To detect food poisoning organisms, researchers have developed a laser-based system. The system is based on a feature of microbial growth, with its movement. As bacteria grow and divide on a surface there is the appearance, at the microscopic level, of growth. It is this apparent ‘movement’ that researchers are have successfully detected.
Detection is through the measurement of dynamic speckle intensity patterns. These patterns are reflected from food samples and can be registered by a scanning laser light. With this, Technology Review explains, when a red laser beam strikes biological tissue, the laser beam is scattered through the material. The scattering causes the light to interfere, creating a random pattern called laser speckle. The speckle appears different when bacteria are present compared to when they are absent.
To date the study is a proof-of-concept one, to see if further research is worthwhile. In studies, the organisms Escherichia coli and Bacillus cereus on chicken breast tissues were successfully detected. On this basis, further research will be undertaken. However, the technology remains a long way from commercialization.
A limitation of the method is that a certain population of bacteria is required to be registered and the device cannot differentiate between harmful and non-harmful species. In addition, viruses, far smaller than bacteria, cannot be detected.
The study was undertaken at the Korea Advanced Institutes of Science and Technology in South Korea. The findings are published in the journal Quantitative Biology, where the research paper is titled “A simple and rapid method for detecting living microorganisms in food using laser speckle decorrelation.”
In related news, Digital Journal has recently reported on the need for better education so that store workers clean and disinfect the meat slicers used in deli stores to a better standard. A second factor influencing incidences of food contamination relates to the environment.
