Infrared Detects E. Coli In Beef Within An Hour Instead Of A Week Protecting Public Health More Efficiently

Editor's Choice
Main Category: Infectious Diseases / Bacteria / Viruses
Also Included In: Medical Devices / Diagnostics;  Biology / Biochemistry;  Nutrition / Diet
Article Date: 02 Sep 2010 - 8:00 PDT

email to a friend   printer friendly   opinions  

Where's the beef? Rather, where are the Escherichia coli (commonly referred to and spelled as E. coli) in my beef? It has been found that infrared spectroscopy detects E. coli (named for discovery by German pediatrician and bacteriologist Theodor Escherich) far more rapidly than current testing options. Utilizing infrared would speed up the detection process dramatically, and potentially curb outbreaks. In addition, spectroscopy can identify strains of E. coli (such as 0157:H7) in much less time than the current seven days necessary to complete the multi-step identification process. About 70,000 American public health cases are documented by E. coli each year, according to the Centers for Disease Control and Prevention.

What about all the other bacteria contained in beef distorting this rapid turnaround of results? Lisa Mauer in a research article published in the August edition of the Journal of Food Science and funded by the U.S. Department of Agriculture, Agricultural Research Service and the Purdue Center for Food Safety Engineering replies, "Even with all the other bacteria present in ground beef, we could still detect E. coli and recognize different strains."

Mauer, an associate professor of food science, identified E. coli in ground beef within one hour using Fourier transform infrared spectroscopy (FTIR). FTIR is a technique which is used to obtain an infrared spectrum of absorption, emission, photoconductivity or Raman scattering of a solid, liquid or gas. This supersedes the 48 hours previously necessary to culture cells in a science lab. Mauer strongly suggests that these same labs that culture use spectroscopy in addition to conventional techniques that detect this Gram negative rod-shaped bacterium.

A filtration method achieved results in about an hour. An antibody-capture method, which binds bacteria to antibodies attached to magnetic beads, produced results in four hours.

In a 12.5% increase in efficiency, spectroscopy can detect as little as one E. coli cell if the bacteria are cultured for six hours. Conventional plating techniques used for E. coli detection require culturing cells for 48 hours.

Mauer continues, "Energy is only absorbed by certain components of a sample. If that component or bacteria isn't there, the energy is reflected back."

E. coli has a unique and specific infrared spectrum that can be read using the FTIR tool. In a simple process, first infrared light is run over a sample. Then, a spectrometer quickly reads the combination of the energy's spectrum hence created. The reflection back from the sample consists of absorbed energy from the infrared lighting.

E. coli infections come most often from post-ingestion of contaminated foodstuffs with the bacteria, which originate from feces. The most common, yet severe symptoms include stomach cramping, diarrhea and vomiting. Fatalities caused by the infection are rare, but can occur.

Unlike current testing procedures, Mauer's innovative spectroscopy methods also can differentiate between living and dead E. coli cells.

"If the cells are dead, they're not harmful. But the presence of that dead population could tell you something about the quality of the product."

Mauer's discovery in testing ground beef can most likely lead to the detection of pathogens in other food types. In line with this prediction, the researcher has already shown that spectroscopy can detect melamine. In 2008, melamine in powdered milk infected approximately 300,000 infants in China and killed at least six.

Source: Purdue University

Written by: Sy Kraft, B.A. - Journalism - California State University, Northridge (CSUN)
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

• Additional
• References
• Citations