A California cheese maker whose raw milk Gouda was the source of an E. coli outbreak that sickened 38 people is back in business and says it will now pasteurize its cheese–at least for the time being.

Bravo Farms of Traver, CA., a pioneer of artisan-crafted cheese in the state, recalled its inventory in November after health authorities made an epidemiological link between a five-state outbreak of a rare strain of E. coli O157:H7 and cheese handed out as samples and sold during a Costco promotion.

Later, the New Mexico Department of Health found the unusual outbreak strain in an unopened package of Bravo Farms Cheese, and bacteria matching the outbreak strain were found in at least two unopened packages.

Of the 38 people who became ill with E. coli infections after eating the cheese, 15 were hospitalized and one developed hemolytic uremic syndrome, or HUS, a potentially life-threatening complication of E. coli infection, the Centers for Disease Control and Prevention said in its last investigation update. A 1-year-old and an 85-year-old were among those who got sick, the CDC said.

According to local news reports, the recall of its cheese and halting operations cost Bravo Farms about $1.5 million and caused it to reduce its staff by half. It resumed production Jan. 1 with a staff of five, the Valley Voice reported.

Bravo co-owner Jonathan Van Ryn told the Visalia Times that the cause of the contamination still hasn’t been determined, but appeared to be “an isolated instance during a single day of production.”

The Visalia Times also reported that Bravo Farms has now begun pasteurizing its cheese because of “the contamination incident” but “has not ruled out returning to a pure raw milk process in the future.”

Van Ryn told the newspaper the company will use a pasteurization method involving heating the cheese at a lower temperature over a longer period of time to maintain the raw milk flavor.

Van Ryn told the Business Journal that “fermentation is supposed to be the natural defense against pathogens” but that “for some reason, it didn’t work, or it was during packaging that it got contaminated.”

The Business Journal also reported that Van Ryn said Bravo Farms might make raw milk cheese again but likely would age it longer than the 60-day requirement and conduct finish product testing, something he said wasn’t needed before. “We had a history of 20 years of cheese-making and we never had a reported illness,” the newspaper quoted him as saying. “You don’t go testing every block when you’ve never had a problem.”