Liquid crystal technology speeds up foodborne pathogen detection

Crystal Diagnostics has pioneered liquid-crystal technology that enables smart fast detection of bacteria and other dangerous pathogens such as E. coli in foodstuffs.
Crystal Diagnostics has pioneered liquid-crystal technology that enables smart phones and flat-screen TVs to transform food testing, quickly illuminating the presence of bacteria and other dangerous pathogens in meat and produce.
The firm recently unveiled a new approach to detect food contaminants such as E. coli. The biosensor relies on the unusual properties of liquid crystals – tiny molecules that can flow like water or freeze like ice. Existing tests involve either coaxing a sample of a suspected pathogen to grow in a lab dish (which can take several days to identify a single contaminant), or making copies of a possible contaminant's DNA, then identifying its unique signature. The latter process is quicker, but still takes hours. Using liquid crystal technology developed at Kent State University and the Northeast Ohio Medical University, the new MultiPath tester can detect multiple pathogens in half an hour or less.

The announcement comes at a time when food contamination outbreaks are once again in the news. In Germany less than a year ago, an E. coli outbreak killed 31 people and infected thousands more. The Centers for Disease Control and Prevention estimates that each year 48 million Americans get sick, 128 000 need hospital care, and 3000 die from foodborne diseases.
Given that US meat and poultry producers cannot distribute their goods until government pathogen test results are known, fast testing has obvious advantages: shorter storage times and the avoiding of delays that could affect food freshness and sell-by dates.

Crystal Diagnostics' technology relies on the ability of liquid crystals to block light. Each antibody can recognize and latch on to a specific kind of pathogen. This is where the liquid crystals come into play. A pinch of crystals is added to a food-antibody mix, then the sample is read by the electronic reader. At the right temperature, liquid crystals can be made to line up in ordered rows, forming a tight matrix that prevents light from passing through. However, if there are clumps made of antibody-coated beads and their target bacteria in the matrix, the liquid crystals cannot align tightly enough to prevent focused light from shining through. An optical detector registers the presence of food contaminants as points of light on a dark background. The results are beamed to a smart phone or iPad. Several contaminants can be identified in the same test run.