Amer AbuGhazaleh, a researcher from Southern Illinois University Carbondale’s College of Agricultural Sciences, and Salam Ibrahim, a food microbiologist from North Carolina Agricultural and Technical State University, have shown that the combination of certain bacteria and a common purple dye can reveal the presence of toxins in milk in just a few hours.
“To date, detecting the presence of toxins or pesticides has only been possible by sending samples to a laboratory and waiting a few days for the results,” AbuGhazaleh said.
“An important step toward improving the safety of our dairy supply would be the development of an effective, simple and rapid test that would allow farmers or processors to detect the presence of foreign substances.”
AbuGhazaleh and Ibrahim first began thinking about developing a way to detect tainted milk quickly in 2007, after a series of food recalls shook the country.
“We were surprised at how much damage that caused, and people were so frightened,” AbuGhazaleh remembered.
The pair also harked back to fears, generated after 9/11, of mass poisonings caused by bioterrorists.
“It seemed like it wouldn’t be hard to contaminate the food supply -- intentionally or unintentionally -- especially with the poor level of security on the majority of farms today,” AbuGhazleh said.
They started with milk in part because AbuGhazaleh specializes in dairy cattle. But they also knew the milk supply was particularly vulnerable.
“A single load of contaminated milk from one dairy could spread that contamination quickly across a wide area as it mixed with milk from other dairies at the processing plant,” AbuGhazaleh noted.
After tossing around some ideas for a simple detection system, the scientists decided to focus on the bacteria that ferment lactose (milk’s sugars), producing lactic acid as they go.
“For one thing, these bacteria already exist in milk, so if you add some, you’re not doing anything strange,” AbuGhazaleh said.
"Second, they produce a change over time (the lactic acid) that we could monitor. If we didn’t see the change, we would know something was wrong.”
They began in 2008 with a few bacterial strains they already had and cyanide, also readily available. Experiments showed not only that the toxin could slow or stop lactic acid production but that this effect increased with the toxic load. Further, the effect appeared in less than four hours.
They then added purple dye to milk samples containing both toxins and bacteria and to samples containing only bacteria. After eight hours, dye in the non-toxic milk turned yellow, indicating the presence of increased lactic acid, while dye in the toxin-laden milk retained its original purple.
“This kind of color test could be performed by farmers themselves,” AbuGhazleh said.
“They could add the bacteria and the dye to a sample, leave it alone for a little while and then come back to see if there is any change in the color. If there isn’t, there are problems with the milk.
“The test won’t tell us what sort of toxin is in the milk; it only tells us there is something wrong. It’s like an alarm.”
Such an alarm could save society billions of dollars. In 2005, Stanford University researcher Lawrence M. Wein and then-graduate student Yifan Liu developed a mathematical model predicting what would happen if terrorists slipped four grams of botulinum toxin -- roughly the weight of a sugar cube -- into a single dairy holding tank, tanker truck or processing silo in California.
Their model showed that 400,000 people would sicken; some of those would die. The cost of treating the victims, the researchers said, would run to “tens of billions of dollars” -- and that does not include the further costs of tracing, recalling and discarding milk nor the effect of reduced milk purchases by frightened consumers.
With funding from the Illinois Council on Food and Agricultural Research, AbuGhazaleh and Ibrahim now are expanding their study to include a wider range of bacteria and toxins.
“We want to see if there are bacteria that are more sensitive to toxins, which would allow us to see the effect in less time,” AbuGhazaleh said.
“We also want to find that ‘universal’ bacteria that would be sensitive to a wide range of toxins.”
AbuGhazleh presented the preliminary results in 2008 at the annual meeting of the American Dairy Sciences Association in Indianapolis.
“There was a lot of interest, particularly in potential commercial applications,” he said.
“That’s the main thrust of this project, but long term, we think the concept -- using naturally occurring microbes to detect contamination -- might extend to other food industries.”
K.C. Jaehnig | Newswise Science News
New malaria analysis method reveals disease severity in minutes
14.08.2017 | University of British Columbia
New type of blood cells work as indicators of autoimmunity
14.08.2017 | Instituto de Medicina Molecular
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
21.08.2017 | Life Sciences
21.08.2017 | Information Technology
18.08.2017 | Life Sciences