The making of "on-chip PCR in real-time" for food quality control

Economical, religious, and health reasons demand an accurate control of food in order to protect consumers from falsely labeled products. Meat in particular is easily susceptible to fraudulent labeling, mainly through contamination with species of lower value. New methods and protocols for rapid, sensitive and reliable identification of extraneous species in food are therefore required. The miniaturization and optimization of analytical methodologies are powerful tools in this direction, especially when connected to Lab-on-a-chip (LOC) microdevices. LOCs possess many advantages, such as the reduction of the analysis cost, the possibility to save time and labor, the easiness of use and not last, the possibility to bring a complex technique out of the laboratory. Here we present a new concept for the food quality control, i.e. the use of LOC for the detection of exogenous DNA in meat via on-chip PCR in real-time. LOC surfaces were treated with different coatings in order to optimize the DNA extraction directly from meat homogenates (bovine, pork, horse). On the same LOC used for DNA purification, we set up the on-chip PCR with real-time detection. Over 1,000 beef genomes, up to 0.01 horse or pork genomes were successfully detected in binary mixtures of pre-purified DNA and similarly, up to 0.01 % parts of exogenous meat were detected in binary mixtures of meat homogenates. The successful on-chip detection of exogenous DNA is a promising step toward the production of an effective microdevice for rapid, sensitive, and reliable identification of meat adulteration.