A new, faster method of detecting Eschericha coli in food -- in hours rather than days -- has been developed by Cornell University researchers.

"As far as I can tell, this is the fastest method of analysis in the arena," said Carl Batt, Cornell professor of food science. "The most rapid method of detecting E. coli O157:H7 is now about 48 hours. With this method, a lab can determine if E. coli is present in certain foods in about seven hours."

The research of Batt and John Czajka, Cornell graduate student in food science originally from Orland Park, Ill., appears in the December 1996 issue of the Journal of Applied Bacteriology and is titled "A solid phase fluorescent capillary immunoassay for the detection of Escherichia coli O157:H7 in ground beef and apple cider."

E. coli is a food-borne bacteria that causes hemorrhagic colitis and hemolytic uremic syndrome, two problems that can be deadly to children and elderly adults. A recent outbreak of

E. coli in the Pacific Northwest is suspected to be caused by the consumption of unpasteurized apple cider and unpasteurized apple juice. Three years ago, an outbreak of E. coli was blamed on contaminated hamburger meat not cooked at a high enough temperature at a chain of fast-food restaurants. Heat, whether through cooking or pasteurization, kills E. coli.

Many scientists believe the current E. coli outbreak might be blamed on the common practice of using apples from the "orchard floor" for cider. Wild or domestic animals leave their fecal matter in orchards where they roam. The fecal remains, carried through in the apple cider production process, may bring E. coli along with it.

The Cornell breakthrough means that health officials or laboratories may be able to detect E. coli in potentially contaminated food with unprecedented speed and accuracy. Currently, it takes days to determine if E. coli is present in food. With this new immunoassay -- a type of analysis -- the detection now may be done in hours.

"This method seems to detect E. coli better than any method out there right now," said Batt, whose Cornell research was sponsored by Idetek of Sunnyvale, Calif., the owner of the patent. The technology is not yet available for the marketplace. "We have documented the utility of this method, but its accuracy in market samples needs to be determined."

The assay is carried out in simple, thin glass tubes, which increases the sensitivity of the method. Bacterial cells are "captured" from the food using microscopic magnetic beads and then placed into a growth medium that allows the bacteria to replicate, making their detection easier. After a few hours incubation, the researchers then added an antibody specific to E. coli O157:H7 that is marked with a fluorescent dye. The antibody binds to the E. coli and fluoresces when illuminated with a laser -- providing the lab positive results that E. coli was indeed present. It is extremely sensitive, able to detect as few as 100 bacteria per 8 ounce sample.

Batt said he hopes that as an extension of this technology, other inexpensive, rapid assays can be developed over the next few years. Despite the relative speed at which the test can detect E. coli, Batt cautions that this test is not ready for routine field testing of apple cider. "There are a number of steps that still require additional refinement," he said.