APR 02, 2015 4:30 PM PDT

Food poisoning: New detection method for bacterial toxin

WRITTEN BY: Robert Woodard
Typical growth pattern of Bacillus cereus colonies in petri dishes.The Bacillus cereus bacteria is one of the potential causes of food poisoning. Indeed, a recent study in Analytical and Bioanalytical Chemistry shows that this versatile pathogen produces 19 different variants of a poison that causes nausea and vomiting in human beings. This variety could explain why some cases are relatively benign and others can result in death.

Across Europe, the number of food poisoning cases caused by the Bacillus species is on the rise. While unpleasant, infections resulting from B. cereus are usually not life-threatening. Depending on the toxin that is released by the bacteria, patients suffer either from diarrhea or from nausea and vomiting. The results can be more serious, however, with death occurring in some very rare cases.

The form of the illness that causes nausea and vomiting is known as emetic. The toxin responsible for this is cereulide. Researchers from Technische Universität München (TUM) and the University of Veterinary Medicine in Vienna have now developed a method for detecting this toxin. In the process, they identified 18 further variants to add to the cereulide already known to scientists.

Ready meals increase the risk of food-borne infections

Recently, around 100 children and staff contracted a B. cereus infection at a number of daycare centers near Paderborn in Germany. It turned out that they had all eaten rice pudding supplied by the same caterer. It is known that consuming pre-prepared meals increases the risk of food poisoning. The types of foods most likely to harbor B. cereus are starchy staples like rice, pasta and potatoes.

"A poor temperature management often plays a role," explains Prof. Thomas Hofmann from the Chair of Food Chemistry and Molecular Sensory Science.

"The bacteria multiply, for example, in food that has been pre-cooked and then not heated up enough, or else not adequately cooled down beforehand."
In addition, B. cereus can produce spores that can survive high heat - and which are still capable of producing viable bacteria at lower temperatures. These then often form bacterial toxins, which are in turn heat-stable - like cereulides.

Toxin attacks cell membrane

The toxin attacks the membrane of living cells. As for their structure, cereulides are like pincers grasping a potassium ion. The potassium ions alter the electric potential at the cell membrane, resulting in damage to the membrane and cell death.

"The toxicity of the individual types of cereulides depends on their chemical structure. The more lipophilic they are, the easier it is for them to attach to the membrane composed of fatty acids," says Prof. Siegfried Scherer, head of the Chair for Microbial Ecology.

New detection method is being evaluated

"Prior to this project, there was no satisfactory method of detecting the cereulide toxin in food," relates Hofmann. "With our mass spectrometry-based process, we have created an important starting point for the reliable detection of the toxic bacteria."

This will make it easier to assess the risk inherent in contaminated products - and the role played by the individual cereulide variants. The new detection method is currently being jointly evaluated at European level together with the US Food & Drug Administration (FDA), and preparations are being made for its deployment.

Source: phys.org
About the Author
You May Also Like
SEP 10, 2020
Space & Astronomy
Could There Be Life on Venus?
SEP 10, 2020
Could There Be Life on Venus?
Venus is the hottest planet in our solar system, reaching 465 degrees Celcius- a temperature hot enough to melt lead. Wh ...
OCT 29, 2020
Microbiology
Metabolomics and the Microbiome
OCT 29, 2020
Metabolomics and the Microbiome
The average person contains large variations in bacteria from the mouth, the skin, sweat, and in the stomach and intesti ...
NOV 02, 2020
Microbiology
A Bacterial Virus Can Help Salmonella Spread
NOV 02, 2020
A Bacterial Virus Can Help Salmonella Spread
The Salmonella bacterium is to blame fora lot of foodborne infections, many of which cause only mild illness, though oth ...
NOV 08, 2020
Microbiology
Seasonal Illness - Is the Sun Involved?
NOV 08, 2020
Seasonal Illness - Is the Sun Involved?
There is a cold and flu season, and many researchers have tried to explain why the viruses that cause these illnesses te ...
NOV 09, 2020
Microbiology
Fighting COVID-19 with Help From Llamas
NOV 09, 2020
Fighting COVID-19 with Help From Llamas
Camelids, which include llamas, alpacas and camels have immune systems that generate two kinds of antibodies when confro ...
NOV 14, 2020
Microbiology
The Structure of a Bacteriophage DNA Tube is Revealed
NOV 14, 2020
The Structure of a Bacteriophage DNA Tube is Revealed
Some viruses only infect bacteria; they care called bacteriophages or phages for short. As antibiotic-resistant bacteria ...
Loading Comments...