Officials said the four people - a 7-year-old from Monmouth County, a 2-year-old from Bergen County, and two women, 34 and 41, from Camden County - got sick from May 23 to June 3.
Salmonella causes diarrhea and abdominal pain. Most people recover within a week without treatment.
The Bergen County boy has recovered and the women are not hospitalized. State health officials didn't immediately release information about the status of the Monmouth County boy.
The U.S. Food and Drug Administration has linked the outbreak to consumption of some raw red plum, red Roma, round red tomatoes, and products containing these raw tomatoes.
State officials have begun random inspections of wholesale produce processors and distributors to check the source of tomatoes shipped into New Jersey. They're also looking at companies' record-keeping practices and handling procedures.
New Jersey tomatoes have been cleared. This year's crop will begin to be harvested next week, according to Agriculture Secretary Charles M. Kuperus.
