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Isotopes Aid in Traceability

Did you or someone in your family buy Lucerne eggs?  Could you easily discern from that package exactly where those eggs came from?  When they were harvested? Where they were washed, shipped, transshipped, and sold?  What if you could answer all of those questions on the Internet by punching in a code number found on the egg carton? Sounds implausible?

Consumers already are demanding this type of transparency in their food supply. After a series of massive recalls covering peanut butter, lettuce, spinach, tomatoes, and now eggs, momentum is building to create a far more extensive food origin tracking system. Such a system could and should give everyone involved in the food chain–from the farmers feeding the hens to the families cooking the eggs for breakfast–a complete picture that goes far beyond mere bar codes on a box.

In fact, Mother Nature’s own barcode could be the underpinning of this new system. Scientists can use something called stable isotopes to establish what is effectively a molecular-level fingerprint for food products coming from a given location, farm, region, or factory.  

Isotopes are slight variations on molecules.  For example, eggs from hens that drank water on a farm in Iowa would contain water (hydrogen and oxygen molecules) with different stable isotope ratios than eggs from hens that drank water on a farm in Arizona.

Scientists have not yet figured out precisely how to extract water from eggs in a way to ascertain these stable isotopes in a production environment. But such a method may be possible, considering that scientists have been able to pull stable isotope ratios out of other mixed substances that contain water such as urine, beer, milk, and fruit juices.

Once you stack up enough of these isotope relationships, it quickly becomes possible to create isoscape maps that match stable isotope ratios to specific regions or locations. An isotopic signature can also easily be converted in a unique identifier or a printed bar code.

Until recently, measuring stable isotopes was extremely costly and cumbersome. The legacy instruments used for stable isotope measurement are called isotope ratio mass spectrometers (IRMS). These instruments cost hundreds of thousands of dollars and require skilled scientists to manage and prepare samples. IRMS instruments cannot be easily moved–IRMS companies charge $10,000 or more to move one–and suffer considerable down-time due to regular required maintenance and calibration. For all of the above reasons, IRMS systems could not achieve the high-throughput or cost levels required for true integration into the country’s vast food supply system.

That has recently changed with the introduction of a novel technology for stable isotope measurements. Called Cavity Ring-Down Spectrometry (CRDS), this technology costs a fraction of an IRMS system, is fully portable, does not require a climate-controlled environment, and can be operated by a lightly trained technician.

A single machine can easily achieve sample throughputs of over 100 per day, making integration into a production line, a wholesale resupply, or a large farm operation possible. For some applications, CRDS actually provides even more accurate and precise measurements than IRMS systems. For this reason, CRDS could provide a backbone for building out a molecular level food origin verification system that would provide an incredible level of transparency for most unprocessed foods (such as milk and produce–and possibly eggs) and for many processed foods, as well.

Coupled with the existing food tracking system, a national isotopic signature network for our food system would put in place an immutable, easily verifiable mechanism that could let consumers trace back a batch of bad eggs to the farm as soon as they feel sick to their stomachs.

Whereas the Food and Drug Administration often must negotiate for days or weeks to cement food recalls (which it can only request and not mandate), giving consumers the power to make more informed decisions would allow the public to quickly vote with their wallets, the media to quickly report on outbreaks, and the food industry to more quickly react to problems as they occur.

Really, this all goes back to trusting Mother Nature. Stable isotopes are Mother Nature’s own bar code system. Mother Nature can’t and won’t lie, won’t delay, won’t protest. Trust Mother Nature with the safety of our food system and no one else. 

© Food Safety News
  • Douglas

    I wonder at the conclusiveness of this method under Biologically dynamic circumstances?