Small-scale farmers weren't the only ones displaced by the industrial food revolution.

Small-scale farmers weren't the only ones displaced by the industrial food revolution.

Vast armies of beneficial bacteria — or probiotics — were driven out of the modern diet, along with fermented foods that traditionally played a role in health.

"Probiotics are like a front-line defense system," says Courtlandt Jennings, of Ashland. "It's sort of a lost part of the nutrition cycle."

Often obtained from cultured dairy products like yogurt, buttermilk, sour cream or kefir, probiotics also reside in sauerkraut, brine pickles, fermented soy foods like miso and tempeh and the lesser-known tea-based beverage kombucha.

"Not everybody wants to have dairy," says Josh Hersk, of Ashland Food Co-op.

Researching the beneficial properties of tea, Hersk realized he could reap greater health rewards if he fermented the beverage. A friend who worked with him at the Co-op provided the kombucha culture, Hersk set it loose in his home kitchen and Living Tea was born.

"Something about it just seemed like a key ingredient that was missing from the modern, American diet," the Ashland resident says.

The microorganism that multiplies at room temperature to create sweet-tart kombucha feeds on tea leaves and sugar. The longer it ferments, the more sour the resulting beverage will be, Hersk says. He adds fruit juices and botanicals to create blueberry and lemongrass flavors. At a commercial kitchen in Talent, Hersk also makes "water kefir," a nondairy drink using cultures similar to those in kefir that consume sugar, dried fruit and lemon juice.

For $2.99, consumers get more than just 16 ounces of tasty, healthful liquid. Provided it's an unflavored variety, Living Tea contains all the cultures needed to start another batch of kombucha. Just add it to any true tea — black, green, white or pu-erh, Hersk says.

"You still have to continuously take care of them," he says of the kombucha cultures. "It's kind of an old, hippy thing."

The hippie haven of Berkeley, Calif., acquainted Jennings with "gourmet" sauerkraut, the unpasteurized version that everyone's grandmother used to make several generations ago, he says. Jennings brought his experiments in probiotic pickles to Ashland and launched the brand Pickled Planet in 2002.

Because vegetables preserved and pasteurized in vinegar already held a prominent position on store shelves, Jennings focused on sauerkraut. He employs vegetables that complement cabbage — carrots, radishes and beets — and adds aromatic spices like caraway and curry or chilies for the staple Korean condiment kimchi. A jar sells for $5.50.

"Sauerkraut is the best dairy-free source of probiotics," Jennings says.

The method of manufacture couldn't get much simpler. Jennings mixes shredded cabbage with salt and packs the mixture into a barrel. In the absence of oxygen, lacto-bacilli colonize the cabbage, eating the vegetable's store of sugar and producing lactic acid, which translates into a tangy, sour flavor.

"It's a fascinating symbiotic relationship," Jennings says. "The majority of people eat it because they know how good it is for them."

Probiotics promote health by prohibiting the growth of harmful bacteria in the human body and the proliferation of other problematic microorganisms like candida, also known as yeast. Although mainstream medical practitioners have not acknowledged the persistence of this fungus as a systemic condition, alternative practitioners often prescribe probiotics to combat "chronic yeast."

More than half of her patients suffer systemic candida, says Mary Lou Follett, a nurse practitioner at Ventana Wellness in Medford. Instead of cropping up as a vaginal, oral or skin infection, yeast more often is the culprit behind sinusitis, chronic bronchitis, inflammation, neurological disorders and digestive disturbances, Follett says. Diets containing too much refined sugar and flour, she says, are largely to blame.

"Our diet's changed," Follett says, referring to Americans' penchant for processed foods.

Follett says she used to prescribe probiotics in cases of chronic yeast but then realized the supplements did little good if patients failed to change their eating habits. She now recommends a diet of whole foods devoid of anything processed to help beneficial bacteria "recolonize" the body. Similarly, Follett decries misleading sources of probiotics, like some yogurts that also contain a lot of sugar, which works against the very bacteria enlisted to help.

"It's really important to research what you're getting."

Foods alone likely aren't enough to restore the body's balance of probiotics, making supplementation necessary for most patients, Follett says. While supplement companies abound, probiotics don't have to be expensive, she says, adding that Ventana sells a month's supply of Probiotic Pearls for $14.95. The brand is widely available at health-food stores, she says.

Some probiotics capsules must be refrigerated because they contain freeze-dried cultures in a dairy base, making it important to gauge whether the package was handled properly from factory to retailer. A preference for probiotics in pill form has increased interest in the Co-op's supply, says Hersk, who mans the store's supplements department.

"A lot of people will just take probiotic capsules," he says.

Yet he encourages customers to try kombucha and kefir for other benefits derived from the whole food. Probiotics, he says, don't just keep the bad bugs at bay.

"They're key for breaking down the nutrients in the food that you're eating."