Automated Food DNA Purification for Authentication and Genetically Modified Organism (GMO) Testing

The ability to trace and authenticate a food product is of major concern to the food industry. It has implications in consumer protection and regulatory compliance as well as cultural and religious aspects. Advances in molecular technologies and genomic analyses of food sources enable screening at the nucleic acid level. Here, we examine the utility of a small benchtop automated instrument, the Maxwell 16, and novel cellulose-based magnetic particles for purification of amplifiable DNA from a variety of foods. We choose 4 key areas of interest for food ingredient testing: genetically modified organisms (GMO) detection, seafood identification, seed screening (rice and coffee) and meat product testing. For each area, nucleic acid was extracted, quantitated, and tested for amplifiability in either end point or quantitative PCR. For GMO testing, extracted DNA from both dried kernels and processed foods (chips and pretzels) were tested for the presence of cauliflower mosaic virus (CMV) sequence. Results showed amplification of CMV sequences in GMO branded samples only. For seafood authentication, DNA was extracted from processed and frozen tuna and salmon and successfully amplified using endpoint PCR of cytochrome b, typically used for fish species identification. For seeds, DNA was purified and demonstrated to be amplifiable from rice (medium grain and basmati) and coffee beans (Arabica and Robusta). Meat testing focused on isolation of amplifiable nucleic acid from processed foods including ravioli, sausage and gelatins. These studies together demonstrate the use of the Maxwell® 16 System for automated purification of food DNA upstream of amplification-based GMO and authentication testing.