Scientists engineer ‘glow in the dark’ bacteria – to help spot the bugs that cause food poisoning
The new technique means scientists can detect infected foods faster than current testing allows
GLOW-IN-THE-DARK bacteria could help make food poisoning a thing of the past, experts have revealed.
They hope by engineering fluorescent E.coli bugs they will be better able to detect the germs.
A team of scientists at Purdue University in Indiana have created a bacteriaphage called NanoLuc - a virus, which only infects bacteria.
Once inside the bugs the virus produces an enzyme that causes E.coli to emit light if they are infected.
The process can shave hours off traditional testing methods, which can be critical when stopping the distribution of tainted foods.
Related Stories
Dr Bruce Applegate, an associate professor of science at Purdue, said: "It's really practical.
"They (testing labs) don't have to modify anything they're doing.
"They just have to add the phage during the enrichment step of the testing protocol.
"We could detect as few as four bacteria in eight hours, and the process is cheaper than tests being used today."
While many strains of E.coli are harmless, some can cause severe and potentially fatal illnesses, the researchers warned.
Ingesting as few as 10 units of a specific E.coli, known as O157:H7, can result in serious illness.
The testing methods that are currently used cannot find a few E.coli O157:H7 cells in a sample.
So scientists do what is known as an enrichment process - this involves culturing the bacteria to encourage it to multiply, so they can be detected.
With the new bacteriaphage added, the Purdue researchers are able to detect the bacteria before that enrichment process is completed.
We could detect as few as four bacteria in eight hours, and the process is cheaper than tests being used today
Dr Bruce Applegate, Purdue University
Dandan Zhang, a graduate research assistant and the paper's first author, said: "The current detection methods cannot bypass the enrichment process, but our technology can explore the enrichment phase.
"That can give us a time advantage over other methods."
The scientists say another positive of the new method is that it should cut down on the number of false positives produced.
This is because the bacteriaphage cannot produce the light-emitting protein without encountering E.coli )157:H7, which is the only bacteria NanoLuc is able to infect.
"The phage is just a virus," Dr Applegate said.
"It cannot carry out metabolism until it infects a bacteria, which in this case is E.coli O157:H7.
"They won't create these proteins unless they've found their specific host."
He said based on the number of bacteriophage added, the amount of time that has passed and the amount of light emitted, they can use an equation to determine roughly how much of the E.coli strain is present.
Their tests were done in a broth made with minced beef.
Mr Zhang said future studies would need to focus on detection of E.coli O157:H7 in lettuce, spinach and other produce.
And they added that other bacteriaphages could be developed to detect other pathogenic bacteria including salmonella.
The new findings are published in Scientific Reports, an arm of the Nature Publishing Group.