Lab-On-Chip to Detect Deadly Bacteria in Food

GLOBAL - Current poultry plants have some inspection for visible damage or bacterial growth, but have virtually no on-site tests for pathogens. There are many sources of such pathogens at the farm, slaughterhouse and processing plant. A new chip developed in Denmark will help detect contaminated cuts on site.
calendar icon 5 July 2008
clock icon 5 minute read

Bacterial outbreaks, most recently with contaminated tomatoes, have sent many to the hospital, even killing a few, reports Daily Tech. In more trite terms of losses, they have robbed us of many of our mealtime staples, thanks to temporary restrictions on sales.

Farmers rue these losses - no spinach, no tomatoes for months at a time - as much as or more than consumers. After all, the crops are their livelihood and when they are pulled off the market, even government relief programs cannot help the farmers recoup their massive financial losses.

Now cutting edge electronics are hoping to both protect the consumer's health and their palate, which should bring relief to farmers. European researchers have developed a prototype lab-on-a-chip test system, which tests food on-site in less than an hour for campylobacter and salmonella. Most food poisoning cases come from these two bacteria.

The new test chip uses microelectromechanical systems including sensors, fluid channels and optical components. The chip is only one of two such systems known to exist in the world.

The goals of the project responsible, the European Union-funded OptoCard project, is three-fold. Its goals are to detect pathogens in the food supply, develop chips to detect pathogens and contaminants in water supplies, and finally develop chips to test human blood for cancer, hepatitis, AIDS and flu.

Jesús M Ruano-López, coordinator of the OptoLabCard project at Ikerlan-IK4 in Spain stated, "The uses for these devices are almost endless… and the market is huge."

While all of these tests are available, currently they require samples to be sent to the lab and processed. This processing is a lengthy process and can take days between the transportation and the analysis on antiquated systems.

Different from previous lab-on-a-chip attempts, the new chip adopts several key technologies. First it ditches specialized materials, forming most of its components from a single thick negative photoresist layer. This allows for cheaper, easier to produce chips. Additionally, the chip is disposable - the expensive optics and electronics are in the supporting reader or base unit.

Perhaps the biggest breakthrough is in the chip design's sample preparation. If a piece of pork containing salmonella was swabbed, only a dozen bacteria might be picked up and past designs would declare it clean. The new chip uses the much used magnetophoresis and the polymerase chain reaction (PCR) technique to replicate bacterial DNA thousands of times. Ruano-López explained, "By using PCR for sample preparation we can create more concentrated bacteria samples, and because it works with DNA it means that the same device can be used to detect many different types of bacteria and diseases."

The chip's first real field test will come as it will soon be deployed in Denmark at poultry farms. Dang Duong Bang, a senior researcher at the Danish Institute for Food and Veterinary Research who will conduct the trial, is pleased that the chip detects campylobacter as it is one of the most prevalent bacteria in poultry. He added, "If the device works as promised and leads to commercial products, it will offer major benefits for farmers, processors and especially consumers."

He points out that infections from the bacteria cause close to US$1 billion in treatment costs in the US and $300 million in Britain a year. By reducing the number of infected animals reaching the market with field tests, great cost savings would be achieved. Ruano-López predicts commercial prototypes to be available within 3 years.

A spin-off company, named microLIQUID, has also been created to market the tech from the project. The partners of the project have also commenced a new project, LabOnFoil, which aims to replace silicon with thin foils in testing systems. The hope is that these efforts will bring the cost down by a factor of ten, down to about 50 cents a test. This would allow for skin patches to monitor disease, contamination and drug abuse.

The new research promises to become a ubiquitous component in industries worldwide. While the average consumer likely holds little interest in the technical details, they will appreciate the benefits - less food poisoning, and less food recalls.

Funding for OptoLabCard was provided by the EU's Sixth Framework Programme for research, while LabOnFoil is being funded by the Seventh Framework Programme.

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