FAQs

Why does rapid matter?

FSMA (the Food Safety Modernization Act) mentions that finished product testing will be part of the food safety system. Rapid testing enables compliance with FSMA without reduction in usable shelf life or the expense of food storage.

How fast is fast enough

For environmental samples, a two hour test enables results in half the time of a four hour sanitation shift. For food samples, a 30-90 minute test provides results when finished product is ready to ship.

What is the total time to result for SnapDNA testing?

We estimate a total-time-to-result of around 75 minutes for a 25mL sample and around 80 minutes for a 100mL sample.

What are the SnapDNA processing steps?

Samples are blended in a paddle blender for 2-3 minutes. The sample is then removed from the blender bag and loaded in the SnapDNA disposable cartridge.  The total time to process the sample is ~70 minutes for a 25mL sample and an additional 5 minutes each 75mL in additional sample volume.

Why does analysis of only live cells matter? How is that accomplished?

“Kill” steps such as cooking, pasteurization, or sanitation are designed to kill pathogens, however they don’t destroy the pathogen DNA.  Confirming the effectiveness of a kill step or sanitation program requires a food safety test that specifically analyzes live bacteria only. As such, analysis of only live cells is a requirement for food safety testing.

SnapDNA has developed a highly accurate, proprietary process to ensure only live cells are detected.  We’re unaware of any other rapid test that detects only live cells.  For example, RNA detection by itself cannot be used to determine whether a cell is live.  RNA degrades after a cell dies but the process can take days.

How large of a sample can be processed with the SnapDNA system?

There is no fixed sample volume limit for SnapDNA processing.  SnapDNA cartridges process samples at 15mL per minute.  Larger samples simply take longer to process.  For example, a one liter sample will take 65 minutes longer to process than a 25mL sample.

Why is it important to support industry methods for sample collection?

Food safety sample size and collection methods are the result of 40 years of industry experience and data analysis. The sponges used in environmental testing have been analyzed in hundreds of papers to access their effectiveness.

Many food safety experts are looking to increase sample size to increase the statistical significance of their testing programs. SnapDNA can process larger samples than current labs tests without a cost penalty

What accuracy is required for routine food industry pathogen testing?
Is 99.9% good enough?

One of the most important accuracy metrics for the food industry is the rate of false positives.  A false positive is when a test incorrectly reports that a sample contains pathogens.  False positive test results are extremely costly.  The industry reacts to a false positive as it would to a true positive result; lines are shut down and the production run is destroyed.  A 99.9% false positive rate equates to one false positive every one thousand tests.  A mid-tier food processor performing one hundred thousand tests per year would be shutting down production twice a week for false positives.  Routine food pathogen tests need false positive rates of one in one million.  That equates to 99.9999%.  As such, tests with only 99.9% accuracy cannot be used for routine pathogen testing.  SnapDNA uses targeted cell capture, which is significantly more specific than bacteria enrichment, followed by RNA/DNA analysis to provide the lowest possible rate of false positive results in the industry with expected rates approaching one in ten million.

Can the SnapDNA system be used for sequencing food samples?

Yes, SnapDNA processing should always be used when sequencing food industry samples. Whole genome sequencing cannot be reliably performed on complex samples.  The pathogen cells in the sample must be isolated and the pathogen DNA must be PCR amplified prior to sequencing. Culturing grows a wide range of bacteria and is insufficient to isolate pathogenic bacteria from complex food industry samples. SnapDNA pathogen isolation is far more specific than culturing. SnapDNA processing enables the most accurate and statistically reliable sequencing results.  It is also significantly faster than culture-based sequencing.