Thursday, January 29, 2015

Tracing the contamination source-A new DNA based tool

Food poisoning episodes are increasingly being reported from countries like the US where even the best of growing and processing practices are not able to stop them completely. Naturally in a country where people cook very little at home and depend on market offered foods, the chances of getting infected or exposed to bacterial toxins are very high. It is not rational or logical to expect that every food handling facility can be kept under eternal surveillance because of high cost involved and limited availability of technical personnel equipped with the wherewithal to assess the safety of these facilities. Traceability is the mot urgent need for the safety monitoring agencies to stop food poisoning episodes in order to stop them in their tracks and take preemptive steps to avoid further damage through product recall. With global food trade becoming more and more easier and moving on a fast track, food materials travelling over 10,000 km is becoming very common. Though self sufficiency is a beautiful word, achieving it is beyond the realm of possibility for many countries, thus increasing the interdependence of nations for meeting their food needs. In this context a method for use of DNA solutions with specific identity for spraying on to the surface of produce materials is being developed for any future identification of the source of origin if there is a contingency arising due to infection of the produce. Here is a take on this novel technique.

"In the labs at DNATrek, the scientists create different liquids that each contain a unique DNA sequence. The sequences would be combined with safe-to-eat food additives, such as the waxes that are now sometimes added to the surfaces of apples and cucumbers. Spray-on DNA bar codes help trace food-borne illnesses | Genetic Literacy Project—stamping the produce with their signature genetic bar code. If needed in the case of an outbreak, investigators could use polymerase chain reaction technology to decipher the bar code and determine where the produce was grown and what route it had traveled. According to Anthony Zografos, founder and CEO of DNATrek: If there's a problem at home and there's a piece of the cantaloupe left, you can pick it out of the trash, you can scrub the surface, and all the available information is there and you know exactly where it came from.In only 15 to 20 minutes, scientists would be able to find out all the particulars of the produce. In an outbreak, time is of the essence; lives could be saved. And the technology is relatively inexpensive too. The spray will probably cost $1 for every 1,000 pounds of produce. Compare that to the estimated $150 billion a year that the U.S. directly or indirectly, spends on food-borne illnesses in a year." 

In this scheme of things each supplier is allotted a particular DNA solution which needs to be applied on the surface of the produce and by polymerase reaction the DNA sequence can be determined in about 15-20 min if and when the need arises subsequently at any point in the supply chain to identify the source.. The product currently developed is based on synthetic DNA though DNA derived from seaweed can also be used as it is one of the safest with no safety problem. As the DNA bits used are of small chain length, it is claimed that their presence would have no adverse reaction at the consumer end. Any biotechnology endeavor, especially involving DNA maneuvering, will be viewed with apprehension and therefore this technology also will face hostile reaction from some section of scientists which will have to be overcome with necessary safety data on its use.


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