People in four states including New Jersey who have been drinking raw milk and milk products from the New York-based company Udder Milk have been urged by the Centers for Prevention and Disease Control and Prevention (CDC) to contact their doctors.

In late September, a New Jersey woman became ill with Brucella abortus RB51, a rare but potentially serious bacteria, after drinking unpasteurized milk from the company.

The CDC recommends that anyone who drank raw milk or consumed raw milk products from Udder Milk in the past six months contact their doctor for antibiotics to prevent illness. Pregnant women who have consumed raw milk or milk products should seek medical care immediately. The illness can cause miscarriages and other pregnancy complications, according to the agency.

Untreated RB51 infections can result in long-term health problems including arthritis, heart problems, enlargement of the spleen or liver, and meningitis.

People who have consumed milk and other products made from Udder Milk should check themselves daily for fever for one month and watch for other brucellosis symptoms including muscle pain, lasting fatigue, arthritis, depression, and swelling of the testicles for six months, according to the CDC.

RB51 is a weakened strain of Brucella abortus bacteria used to vaccinate young female cattle. The vaccinated cows can shed RB51 in their milk but pasteurization kills the bacteria.

According to the CDC, the agency has not been able to trace the source of the infection because Udder Milk has not provided them with the names of the farms that supply the raw milk. Udder Milk operates a members-only website "which makes it easy to avoid detection by public health officials," and makes deliveries to Connecticut, New Jersey, New York and Rhode Island, the CDC stated.

Selling and distributing raw milk and raw dairy products is illegal in New Jersey and selling it outside of the farm that produces it is illegal in New York, the agency stated.

The New Jersey woman was the second reported case of illness caused by Brucella bacteria this year. In July, a case was reported in Texas. The two incidents are not related, the CDC reported.