Back to bacteria

Scientists use beneficial 'bugs' to promote health

by Amina Ali

lthough almost everyone is trying to stomp out bacteria in the dairy industry, one group has targeted the benefits of "good" bacteria for consumers.

Prof. Mansel Griffiths and graduate student Stéphane Cadieux, Food Science, along with Guelph food scientist Yukio Kakuda and Owen Ward of the University of Waterloo, are trying to improve the nutritional value of dairy products by adding beneficial fatty acids made from bacteria.

They're looking at omega-3 fatty acids, important nutrients for nervous system and eyesight development in babies that may also prevent cardiovascular disease and cancer in adults.

The researchers are using bacteria to produce omega-3 fatty acids from whey, a waste product of dairy manufacturing that eventually ends up in the environment. They hope strains of the bacteria that produce high levels of omega-3 fatty acids could be used in their procedure to ultimately create a commercially viable process.

If successful, the plan would represent an inexpensive way to create omega-3 fatty acids to add to cows' milk.

"This research has two benefits -- a value-added product with increased nutrients and a reduced impact on the environment," says Griffiths.

Three forms of beneficial omega-3 fatty acids are alpha linolenic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and are produced by marine bacteria. Griffiths wants to add the genes responsible for synthesizing omega-3 fatty acids into lactic acid bacteria, which are used to produce fermented milk products.

As part of another project, Griffiths and graduate students Jane Ellenton and Wenrong Sun are collaborating with food scientist Linda Harris at the University of California, Davis. They're investigating more efficient ways to deliver beneficial bacteria to the gut of humans and animals.

It's been suggested that when certain bacteria such as Bifidobacterium colonize the gut, they protect against infection by foodborne pathogens and produce other positive health effects. The trick is to get them to sites where they can grow without being harmed by adverse conditions in the food or the stomach.

The approach used by Griffiths's team is modelled on a non-dairy beverage being targeted in the United States for teenagers. The drink consists of a fluid component containing gel beads (about the size of a pinhead) suspended within, to impart different flavors to the drink.

The bead suspension technique could be applied to dairy products for probiotics -- bacterial cultures with beneficial health properties. This involves using beads that protect the bacteria from the harsh acidic environment of human stomachs, so the nutrients can be delivered intact.

"We intend to use the beads to immobilize bacteria and tailor the system to a variety of dairy products, such as fermented beverages and cheeses," says Griffiths.

His team is determining the best conditions to promote survival of the bacteria in acidic environments. The bead delivery system itself uses a calcium salt to form the beads. An added bonus of the beads is that this may be an effective way of delivering calcium.

"The dairy industry will derive greater sales from its fermented dairy products," says Griffiths, "and consumers will gain more nutritionally complete food and drinks."

This research is supported by the Dairy Farmers of Ontario and the Natural Sciences and Engineering Research Council.