Biosensors as 21st Century Technology for Detecting Genetically Modified Organisms in Food and Feed

Abstract

T history of genetically modified organisms (GMOs) can be traced to the year 1971, when Ananda M. Chakrabarthy discovered a multiplasmid hydrocarbon degrading bacteria Pseudomonas putida that was capable of digesting an oil spill 2 orders of magnitude faster than four similar strains. Since then, little more than 2 decades, this landmark research paved the way for a “biotech revolution” that allowed genetic transformation of virtually all terrains of life on earth. Mainly in the agricultural sector, in the years between 1997 and 1999 as much as 70−80 million acres were quickly converted to raise genetically modified (GM) food and crops. Predominantly, >40% of the corn, >50% of the cotton, and >45% of soybean acres of land and at least 2/3rds of all the U.S. processed foods contained GMOs. What caused this dramatic revolution lies in the fact that GMOs are unique, and they were mankind-created by forceful modification of their genome through gene technology. Genetic transformation/modification occurs by alteration of an organism gene cassette (Figure 1) consisting of an expression promoter (P), a structural gene (“encoding region”), and an expression terminator (T), by inserting foreign DNA, which enables the expression of an additional protein conferring new characteristics, for example, herbicide tolerance, resistance to virus, antibiotic, and insect resistance. There are two particular sequences inserted into most transgenic plants, promoter of the 35S subunit of rRNA of the cauliflower mosaic virus (CaMV35S) and the terminator of nopaline synthase gene (TNOS) from Agrobacterium tumefaciens. These are used widely in commercial production of transgenic vegetables under the brand names such as soy Roundup Ready, the maize MaisGard, and the tomato Flavr Savr. Currently, the global status of commercialized GM crops reached 170 million hectares in a total of 29 countries, as revealed by ISAAA 2011(Figure 2). Among them the U.S. remains the top with 69 million hectares raising maize, soybean, cotton, canola, sugar beet, alpha-alpha, papaya, and squash, followed by Brazil and Argentina. Despite the great progress of technology, these modified foods have not gained worldwide acceptance in the general public because of raised consumer concerns, environmental issues, transparent regulatory oversight, and skepticism in government bureaucracies. During the early development of this field, when pesticides and other tolerant crops were introduced, it was thought to be safe and harmless for consumers. However, only over a decade, this technology has shown its true harmful implications which now have led to an ongoing debate on increasing research efforts evaluating the risks associated with the introduction of GMO into agriculture (e.g., potential gene flow to other organisms, agricultural diversity destruction, allerginicity, resistance to antibiotics, and gastrointestinal problems). Additionally, economical and moral issues with realization of contamination of non-GMOs with GMOs came into play. Therefore, several countries, including EU countries, Japan, Australia, New Zealand, Thailand, and China have implemented mandatory labeling for bioengineered foods. In the EU, strict restrictions were imposed on the import and introduction of legislation requiring mandatory food labeling in cases where more than 0.9% of the food ingredients (considered individually) are of GMO origin. However, the U.S. legislation instead opted for voluntary labeling and requested companies for U.S. Food and FDA approval before their launch into market. Consequently, 90% of the consumers have no idea what has been quietly introduced into their daily based food consumption and what impact they might cause in the near future.