(Editor’s note: This article has been updated to reflect a communication from the Kentucky Department for Public Health.) The four Kentucky children hospitalized in an E. coli outbreak earlier this month all consumed milk from the same raw milk dairy, according to multiple reports and the mother of one of the sickened children. The Kentucky Department for Public Health has not identified the source of the outbreak. Microbial testing of animals, milk samples, and environmental samples from the dairy in question came back negative for E. coli. Since tests at the dairy did not reveal any contamination, the state health department did not order the dairy to suspend sales. The state health department has not returned calls from Food Safety News looking for updates on the outbreak investigation. On Thursday, a spokesman for the Lincoln Trail District Health Department in Elizabethtown, KY, said that the state health department would be publishing an update by Friday, but it had not yet surfaced as of Monday evening. Update: The Kentucky Department for Public Health has issued a statement to Food Safety News. In part, the statement reads:

The Kentucky Department for Public Health is warning consumers about the dangers of consuming unpasteurized milk as well as other products that could lead to disease-producing E. coli infection, following a recent outbreak in North Central Kentucky and the hospitalization of four children. Confirming a direct link to a given source of food or milk that causes an outbreak can be difficult, especially in situations where exposures occurred over a brief window of time. Laboratory testing has not yet definitively identified the source of the recent illnesses. However, DPH is stressing the dangers of unpasteurized milk after learning all the affected children had consumed it and because it is a known source of E. coli bacteria, as well as numerous other pathogens that can lead to illness. DPH has been working with local health departments, hospitals, and the provider community to investigate the outbreak. Four of the five children associated with the cluster developed Hemolytic Uremic Syndrome (HUS), a disease caused by the most severe E. coli infections which may result in life-threatening kidney failure.

Because no additional illnesses have been reported since the outbreak announcement, the source of contamination is not believed to pose a continuing public health threat, the Lincoln Trail spokesman said. Amy Nordyke, the mother of an 18-month-old boy hospitalized in the outbreak, told Food Safety News that each of the children hospitalized in the outbreak belong to families in the same food club that allows legal access to raw milk from one dairy. Raw milk is not legal to sell at retail in Kentucky, but residents can buy into food clubs — or herd shares — through which raw milk can be legally purchased. Nordyke’s son fell ill with hemolytic uremic syndrome, a kidney disease associated with severe E. coli infections. He spent most of September in the hospital, but was discharged last week and is recovering. Nordyke said three other children from her family’s food club were checked into the same children’s hospital at the same time as her son. Each of those children was also given raw milk by their parents, she said. After the five children fell ill in early September, the food club advised its members to dispose of any remaining raw milk as a precaution, according to journalist David Gumpert. The club did not order any more milk for two weeks, but recently began ordering it again, Gumpert said. Food Safety News will continue to watch for an update from the Kentucky Department for Public Health. As with many foodborne illness outbreaks, the investigation may not uncover enough evidence to conclusively pinpoint a source. Young children are more susceptible to foodborne illness compared to healthy adults due to having developing immune systems. Populations with greater susceptibility to foodborne pathogens also include pregnant women, the elderly, and immunocompromised individuals. According to the U.S. Centers for Disease Control and Prevention, raw milk is 150 times more likely to cause foodborne illness compared to pasteurized milk, and it hospitalizes 13 times more individuals than pasteurized dairy products. (Editor’s note: This article originally stated that five children were hospitalized in the outbreak, as some news outlets have reported. The Kentucky Department for Public Health confirmed that only four children were hospitalized. A fifth child was sickened, but not hospitalized.)