Food processors are converting to new inspection systems to determine the
safety of their products. That means they need quick answers to questions
about the presence of pathogenic bacteria on those products before they
reach the end of the line. A discipline known popularly among scientists
as "rapid methods" is dedicated to exploring ways to shorten the
time it takes to determine the microbiological content of food during processing.
Dr. Daniel Fung of Kansas State University is one of the world's top authorities on the subject. He speaks to audiences around the globe, both scientists and non-scientists, about the quest for safer food through microbiological research. Fung, a professor in the KSU animal sciences and industry department and a principal investigator in the Food Safety Consortium, has elevated his field to a high profile.
Each summer he hosts an international workshop in "Rapid Methods and Automation in Microbiology" at the KSU campus. This year the 16th annual session will be held July 12-19. The conference attracts participants from throughout the U.S. and numerous foreign countries. Many of Fung's guests are people who have attended his lectures during his frequent international travels. He sends out a Christmas card each year containing a world map of the previous year's transoceanic trips.
Fung, an enthusiastic scientist who often arrives at his office well before sunrise, is a prolific contributor to journals, books, and academic conferences. He's often on the go, whether darting across the continent or rushing down the stairs in his campus office building. If you find him with a few minutes of time to spare, he will gladly deliver a compressed version of the latest developments in rapid methods and explain their significance for both the average consumer and the laboratory researcher.
Fung emphasizes that rapid methods for detecting pathogens in food processing is a vital part of the Hazard Analysis and Critical Control Points system (HACCP). It's a science-based system for discovering and eliminating pathogenic bacteria in meats as it goes through the production process, rather than relying solely on visual inspection for visible pathogens at the end of the process. Food processors are responsible for implementing the procedures and maintaining quality control. To do so, they rely on the sort of research performed by Fung and other rapid methods experts.
"If you have a good HACCP program, then you are pretty sure you processed the food properly," Fung said. "If you had good processing, then hopefully at the tail end your food is safe. But these rapid methods will tell you whether you are doing it right or not."
The need for developing rapid methods of identifying the presence of pathogens was driven home when it became apparent that food microbiologists had fallen behind clinical microbiologists in their respective areas of research. "Because of the need to save lives in hospital environments, clinical microbiologists initiated rapid methods in the mid-1960s and accelerated work in the 1970s," Fung said.
Clinical microbiologists' research resulted in the development of several diagnostic kits for use in clinical settings. Through the 1970s, the food microbiologists remained about 10 years behind the clinical microbiologists in development of applicable methods, but then they began to catch up.
"The food microbiologists discovered that they can use some of the clinical diagnostic kits to do things," Fung explained. "They're piggy-backing on the technology of the clinical microbiologists. And a lot of them found they can do a lot also, so the food microbiologists started to get into the rapid methods scenario and the whole field started to move along with the clinical microbiologists."
As the technology advances, food scientists at processing plants can find out in reduced time frames whether food has pathogenic bacteria. Even with the progress made to date, "rapid" still means within a day.
"Everybody would love to have an answer (on pathogenicity status) in four hours, but it's not attainable at this time," Fung said. "Eight hours, maybe, right now. It's realistically one working day. Compare that with conventional methods --- it took seven days to get results on Salmonella or for E. coli 0157:H7."
Seven-day waiting periods were not practical for purposes of assuring food safety. "If you take a piece of food and find seven days later that it has Salmonella, so what? It's already gone all over the place," Fung said. "Now, overnight, you can tell positive or negative for Salmonella or E. coli 0157:H7."
Fung acknowledged that four-hour waiting periods would be the ideal. If a scientist at a processing plant begins conducting a test by 9 a.m., it would be possible to have results by 1 p.m. Then, Fung said, if a problem is discovered a supervisor has time during the day to determine what step to take next.
The length of time required to obtain answers to tests on food samples varies among some tests. Some are almost instantaneous and are simple enough that analysts need only drop samples into a testing unit and obtain the results within minutes. The speed of other tests depends on the complexity of equipment. Many diagnostic kits perform many tests for one organism at a time and some can handle hundreds of samples at a time.
But more work remains to be done before instant answers are readily available for more types of tests. "To make a quantum jump to instantaneous detection of foodborne pathogens in a complex food matrix, microbiologists need to understand more fully the unique characteristics of target foodborne pathogens and potential emerging pathogens," Fung wrote last year in an article for Food Technology. "They must work with biochemists, immunologists, chemists, physicists, biophysicists, electronic engineers, instrumental engineers, etc., to develop new and more accurate rapid methods. The future is bright for this field of endeavor for promoting food safety and protecting the health of consumers nationally and internationally."