April 29, 1999

Cornell food scientists make database of bacterial, genetic 'fingerprints' available on the web

Cornell University food scientists have for the first time made publicly available on the World Wide Web a database of bacterial, genetic "fingerprints." The database includes food pathogens and so-called "probiotic" beneficial bacteria that are ingredients in many health foods and beverages.

"Up to now, identifying certain types of beneficial bacteria for use in formulating products has been primitive at best," says Carl A. Batt, Cornell professor of food science and the director of Cornell's Laboratory for Molecular Typing, which devised the database. "The organisms are so ill-defined, they are hard to identify." Now, food processors and dairy food companies who wish to survey the database to make a genetic identification of specific strains of common bacteria such as Lactobacillus, Bifidobacterium, Lactococcus, Streptococcus and Pediococcus can do so on the web. "Our lab can now do a finite positive ID on the strains of these and other bacteria," Batt says.

Assembled from clinical, environmental and food samples, the public database consists of more than 989 individual genetic patterns representing a total of well over 200 unique genetic families, known as RiboGroups. The database is the result of approximately five years of sample collection and also has been used to track the origins of a number of food- and animal-borne bacterial outbreaks.

Says Batt, "There has been a wave of attempts to standardize natural ingredients in all kinds of products in the food and pharmaceutical industries. Now we have another microbiological standardization issue, and efficacy is strain specific. Through this database, we will be able to fingerprint the beneficial bacteria."

Acidophilus cow milk, widely consumed in the United States, is such a product. Makers of other cultured dairy products, such as yogurt and buttermilk can now see exactly which strains of bacteria they are using in their products.

The molecular typing laboratory established three years ago by Batt, is a fee-for-service facility available to all users who wish to use it to identify and characterize microorganisms down to the subspecies level. The lab uses a microbial identification system, made by DuPont's Qualicon subsidiary, which generates precise and diagnostic genetic bacterial fingerprints. The lab also offers ribosomal RNA sequencing for genus and species identification.

Earlier this year, food scientists at Cornell used the molecular typing laboratory's database to identify a specific strain of Listeria monocytogenes, a potentially deadly bacteria, in hot dogs manufactured in Michigan. Because of the database, the Cornell researchers were able to match the specific Listeria strains and pass the information along to federal and state health officials.