A new outbreak of infections from Listeria monocytogenes is under investigation by the Food and Drug Administration.

As of Dec. 26, there were 31 patients in the outbreak. The FDA has not reported where the patients live. The agency has begun traceback efforts, but has not yet reported what food it is tracing.

In other news, the FDA reports that the number of patients in an E. coli O157:H7 outbreak has increased to 88, up from 86 a week ago. The sick people are spread across 12 states. The illnesses began in mid-November. The FDA first posted information on the outbreak on Dec. 4.

The FDA has determined that the cause of the outbreak is a contaminated romaine/iceberg lettuce blend supplied to caterers, restaurants and a school. The agency has identified the supplier, but continues to refuse to name it. The Centers for Disease Control and Prevention are assisting with the outbreak investigation, but have not yet posted any information on it.

The FDA suggests that the supplier is not being named because all of the impacted lettuce should be off the market at this point. The agency has initiated an inspection of the supplier.

“FDA’s traceback investigation has identified an iceberg and romaine lettuce blend from a common supplier as the source of this outbreak; however, the impacted product identified to date appears to be past shelf life and no longer on the market. FDA is continuing to work with the supplier to determine if any additional product could be impacted,” according to a statement from the agency.

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