Enterococci turned up in water samples from Trenton Avenue Ocean Beach in Lavallette, 5th Avenue Bay Beach in Seaside Park, and 16th Street Bay Beach in Surf City.
The bacteria can cause urinary tract infections, bacterial endocarditis and more.
Swimming advisories are effected when samples exceed 104 colony forming units (cfu) of enterococci. The water will be tested again and, if the second test exceeds the first limit, the beaches will be closed for swimming until levels drop.
The samples at Lavalette and Seaside Park showed more than 600 cfu, and Surf city's sample was 110.
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