Public health officials in New Jersey are waiting on test results in a suspected E. coli outbreak that may be linked to a restaurant chain.

Authorities are investigating six illnesses across three counties wher the restaurant chain has locations, according to a spokeswoman for the New Jersey Department of Health. She said the department will not consider naming the restaurant chain until laboratory tests from foods and victims are available.

Standard epidemiological investigative techniques are underway. Public health staff is working on traceback of possible food sources. They are also interviewing sick people who ate at the suspect restaurant chain to narrow down possible foods.

Anyone who has eaten out in recent days and developed symptoms of E. coli food poisoning should seek medical attention and tell their doctors of the possible exposure to the bacteria. Food contaminated with E. coli O157:H7 may not look or smell spoiled but can still cause illness.

Symptoms can include nausea, vomiting, mild to severe abdominal cramps and watery to bloody diarrhea, according to the Centers for Disease Control and Prevention.

Young children and some elderly victims are at risk of developing hemolytic uremic syndrome (HUS), a severe and sometimes fatal complication of an E. coli infections. HUS strikes approximately 5 percent to 10 percent of STEC-infected children under the age of 10 years, affecting the kidneys, digestive system and other organs. HUS is fatal in 3 percent to 5 percent of cases, while other HUS victims may suffer long-term consequences of their illness, including hypertension or impaired kidney function.