Defining NGS in Food Safety
November 6, 2017
The food safety world is full of acronyms that represent complex concepts, technologies, and regulations. Regardless of how well-versed you are in the industry, providing a brief, clarifying synopsis of industry terms in just a few sentences can be a challenge.
With that in mind, we’ve put together a list of key industry terms related to next-generation sequencing that we hope will come in handy as our industry explores this technology in a collective shift towards more proactive food safety measures. The more we can do as an industry to educate our peers and standardize on language, the faster we can get new technologies adopted for a safer food system.
Feel free to lift these share these with new team members, potential prospects, and in consumer-facing communications. Clearly this is just a first step, but hopefully we’ve saved you a bit of time in communicating the essentials of what you already know in a format you can share.
NGS: Next-generation sequencing. NGS is the most modern, parallel, high-throughput DNA sequencing available. It can sequence 200 to 300 samples at a time and generates up to 25 million reads per a single experiment. This level of information can identify pathogens at the strain level and can be used to perform WGS for samples with unknown pathogens or ingredients.
WGS: Whole genome sequencing. WGS uses NGS platforms to look at the entire DNA of an organism. It is non-targeted, which means it is not necessary to know in advance what is being detected. In WGS, the entire genome is cut it into small regions, with adaptors attached to the fragments to sequence each piece in both directions. The generated sequences are then assembled into single long pieces of the whole genome. WGS produces sequences 30 times the size of the genome, providing redundancy that allows for a deeper analysis.
PCR: Polymerase chain reaction. First described in 1985, PCR is a technique to amplify a segment of DNA and generate copies of a DNA sequence. The DNA sequences generated from PCR must be compared to specific, known pathogens. While it can identify pathogens at the species level, PCR cannot provide the strain of a pathogen due to the limited amount of sequencing information generated.
DNA Barcoding: These short, standardized DNA sequences can identify individual organisms, including those previously undescribed. Traditionally, these sequences can come from PCR or Sanger sequencing. With NGS, the barcoding can be developed in parallel and for all gene variants, producing a deeper level of specificity.
ELISA: Enzyme-linked immunosorbent assay. Developed in 1971, ELISA is a rapid substance detection method that can detect a specific protein, like an allergen, in a cell by binding antibody to a specific antigen and creating a color change. It is less effective in food testing for cooked products, in which the protein molecules may be broken down and the allergens thus no longer detectable.
FSMA: The Food Safety Modernization Act, a wide-ranging and detailed piece of legislation that will impact our food system for decades. Passed in 2011 in the United States, FSMA requires comprehensive, science-based preventive controls across the food supply. Each section of the FSMA consists of specific procedures to prevent consumers from getting sick due to foodborne illness, such as a section to verify safety standards from foreign supply chains. FSMA is currently being rolled out in the food systems across the country.
HACCP: Hazard analysis and critical control points. A food safety management system, HACCP is a preventative approach to quantifying and reducing risk in the food system. It was developed in the 1950s by the Pillsbury Company, the Natick Research Laboratories, and NASA, but did not become as widespread in its use until 1996, when the U.S. FDA passed a new pathogen reduction rule using HACCP across all meat and poultry raw products.