Development of a real-time, NASBA-Molecular Beacon system for rapid and specific detection of live microbes in juice products
Advisor:Wang, Hua H.
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Series/Report no.:Food Science and Technology.
Each year, at least 10-25% of our food supplies are lost due to food spoilage and millions of people become ill from foodborne diseases, causing huge financial burden to the society and threatening public health. Therefore rapid detection of spoilage and pathogenic organisms is a primary task in food industry. The objective of this project is to develop a new real-time, isothermal amplification-based NASBA-Molecular Beacon system so only the presence of live microbes in processed food will be detected. Such a system can minimize false positive results due to the contamination of DNA template from dead cells, and the procedure is more practical than reverse-transcriptase PCR. We have chosen yeasts, a common spoilage agent in food, as the target for the system development. A pair of NASBA primers and a Molecular Beacon probe targeting the 18S rRNA gene of yeasts were designed and synthesized based on homology sequences from the DNA database and spoilage yeast isolates from the food industry. Using the primer-and-probe pair, the presence of less than 100 yeast cells per sample can be detected without cross-activity to molds, bacteria and raw food materials by the NASBA-Molecular Beacon system, and the analysis is completed within 4-6 hours. This is a major improvement compared to current mainstream practices and this new platform has a great potential for food industry applications.