What does ice cream have to do with bacteria?

Robert Roberts, associate professor of food science in Penn State's College of Agricultural Sciences, is studying the effect of probiotics — namely bacteria — in ice cream.

His studies suggest that some bacteria, when added to ice cream, can actually be healthy.

"If it's beneficial to your health, I mean, sure, why not?" said John Tocke (sophomore-biology).

Tocke said his favorite ice cream, bittersweet mint, could only be improved with probiotics.

"Probiotics are living microorganisms, mostly bacteria, that promote well being by enhancing the number of 'good bacteria' in your gut," Roberts said.

Roberts has worked with lactic acid bacteria for about 20 years, but he only recently developed an interest in the probiotic qualities of these microorganisms. His main interest has been the application of these microorganisms in yogurt and cheese.

"When a probiotic microorganism is consumed, it takes up residence in the gut for some time period. When they are resident in the gut, the probiotic bacteria can compete with other bacteria for nutrients and binding sites," Roberts said, adding that this can improve intestinal health.

"For example, the probiotic might not let a pathogenic E. coli bind in the intestine. This is called competitive exclusion. The probiotic may produce compounds that kill pathogenic bacteria that enter the gut," Roberts said.

Probiotics also are thought to stimulate immune system function and to decrease cholesterol, Roberts said. "In some cases it has been shown that cholesterol is assimilated by the probiotic bacteria and the excreted in the feces," he added.

In Europe, Asia and Australia, probiotics are already added to yogurt and ice cream.

"When I was in Australia during the summer of 2000, I noticed a wide variety of probiotic containing products on the shelf," Roberts said.

Currently, the University Creamery has no plans to make a probiotic ice cream, but Roberts suggested that the Creamery might consider making one in the future.

Hillary Cohen (freshman-business) supported the application of probiotics in ice cream.

"If it doesn't change the flavor or have any bad side effects then it's fine because it makes other people able to eat it," Cohen said.

Roberts is currently investigating the effect of the bacteria on the flavor of ice cream to which it would be applied.

"There are a number of methods for introducing probiotics into products. Some of these methods will result in very little, if any change, in flavor," he said.

Roberts hopes to find methods that would allow the probiotic to survive the cold temperatures of freezers.

As for side effects, probiotics are commonly used in food and are not pathogenic.

"I am not aware of any potentially negative side effects with respect to the consumption of probiotics," Roberts said.