At least 19 people who attended a Boy Scout Camp in Goshen, Va., known for hosting Washington area Scouts, tested positive for E. coli bacteria. Health officials said that beef tainted with E. coli was found at the camp in Rockbridge County.

One of the most common causes of E. coli infection is undercooked ground beef. E. coli infection is more often linked to food containing the bacteria. Among the foods that can cause E. coli poisoning are: undercooked ground beef (used for hamburgers), vegetables grown in cow manure or washed in contaminated water, fruit juice that isn’t pasteurized (pasteurization is a process that uses heat to kill germs). Scout officials pulled ground beef, a common source of E. coli, from the camp menu on July 28, imposed sanitary precautions and kept the camp running in consultation with the Department of Health, officials said, according to the Washington Post.

Campers had cooked hamburgers in tinfoil over camp fires, which lead to the hypothesis that the meat was not cooked to a high enough temperature. Heat can kill the bacteria, so health officials recommend that people cook beef (especially ground beef) until is cooked through and no longer pink. It should be cooked to 160 degrees Fahrenheit.

“It just adds more credibility that it [ground beef] may be the cause of the situation, but it is still an ongoing investigation,” said Dr. Douglas Larsen, director for the Central Shenandoah Health District, according to a local source.

The symptoms for E. coli infection include: bad stomach cramps, vomiting, diarrhea, sometimes with blood in it. In some cases, E. coli poisoning can cause life threatening kidney problems. Boys and adults who attended the camp are advised to seek medical treatment if they show any signs of the infection.

The CDC estimates that there may be about 70,000 infections with E. coli annually in the United States, with many of these cases not seeking medical care.