Detecting microbes using the glow worm effect
products are contaminated with microbes uses the "glow-worm"
effect.
Food makers are constantly searching for faster ways of testing their products for contaminants, before they leave the plant.
Many testing methods currently available require samples to be place ina nutrient medium, where they propagate in enough numbers to be detected.
These methods can take up to two days if the bacteria are present in small numbers.
However a number of faster testing methods have been developed or are being developed to speed up the process,especially with the increased regulatory emphasis on food safety.
The latest test method, developed by chemical scientists at Moscow State University, is based on the same principles that allow a glow worm to luminesce.
The scientists estimate the method can test meat and milk within 20 to 30 minutes and up to three hours in complicated cases.
Glow-worms luminesce through a reaction involving adenosine triphosphate, a compound that exists in all cells, including microbes.
If a cell is destroyed and brought into contact with a specialreagent it begins to glow.
The Moscow scientists used the principle to develop their bio-luminescence testing method.
To carry out the analysis a food sample is mixed with a special reagent to make it homogeneous.
The sample is placed in a vessel with a bacteria-filter membrane in the bottom.
As the liquid part of the sample passes through the membrane only bacteria cells remain on it.
Another reagent is added to the membrane, destroying the cells and isolating adenosine triphosphate.
Genetically modified luciferase enzyme is added to the test sample, causing luminescence.
A monitor then registers the quantity of luminescence and estimates the number of microbes.
The scientists say they have synthesised the enzyme required to cause the luminescence.
They have alsoproduced analysis sets based on the technique.
They have established a company called Lumtech to market their method, according to Informnauka, Russia's science news agency.
External links to companies or organisations mentioned in this story: Informnauka