The Food and Drug Administration has posted an increase in the number of patients in an outbreak of Listeria monocytogenes infections as it continues investigations into three other outbreaks.

The new patient count in the Listeria outbreak is 16, up from 14 reported a week ago. As of March 16 the FDA had not determined the cause of the outbreak. The agency has initiated traceback efforts, but has not revealed what food or foods are involved in those activities.

The FDA has not revealed any demographic information on the Listeria patients and has not reported where they live.

In other outbreak news the FDA is investigating a new outbreak of Salmonella SaintPaul infections that has sickened 59 people. The agency announced the outbreak on March 16. As with the Listeria outbreak investigation, the FDA has not released any patient information for the Salmonella outbreak and has not reported where the patients live. Traceback efforts have begun, according to the FDA, but the agency did not report what food or foods are involved.