A mysterious salmonella outbreak continues to aggressively expand in the U.S. and has now sickened at least four people in New Jersey.

There have bee close to 250 confirmed cases, but federal health officials say that number is likely much higher.

The U.S. Centers for Disease Control and Prevention is asking for anyone who has symptoms or been infected to save any takeout containers they may have used and to contact them so they can hopefully pinpoint the source.

The Salmonella Oranienburg strain has now been detected in 29 states from California to New York, New Jersey and Pennsylvania. Federal health investigators have not yet been able to pinpoint the source of the infection.

In at least one case, a takeout container that had cilantro and lime inside did test positive. The customer said there had also been onions in the container, but they had been eaten or discarded and were not available for testing.

In an update on their website, the CDC stated: “Because multiple food items were present in the container and in the sample that was tested, it is not possible to know which food item was contaminated. We are using this information in conjunction with other available information to help narrow the list of possible foods linked to illness.”

Past outbreaks of salmonella or other food-borne infections have often been traced to a single ingredient or food item that was shipped from one location to multiple destinations such as supermarkets and restaurants. While the pattern suggests this could be the case with this salmonella outbreak, no one source has been identified.

Nationally, 26 people have been hospitalized but none in New Jersey, according to CDC data. Salmonella is not typically life-threatening. Most people recover without severe symptoms, which include nausea, vomiting and diarrhea.

Salmonella infection usually isn't life-threatening. However, in certain people — especially infants and young children, older adults, transplant recipients, pregnant women, and people with weakened immune systems — the development of complications can be dangerous. - Mayo Clinic

Salmonella Oranienburg infections have been linked in the past to everything from eggshells to cheese and black pepper.

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