According to the CDC, during January–June 2010, a total of 14 cases of laboratory-confirmed invasive listeriosis were reported to the Louisiana Office of Public Health (OPH). Isolates of Listeria monocytogenes from the blood samples of eight patients were identified as serotype 1/2a and had pulsed-field gel electrophoresis (PFGE) pattern combinations that were indistinguishable from one another. The detection of this cluster prompted an investigation in coordination with CDC, the Louisiana Department of Agriculture and Forestry (LDAF), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS). In-depth epidemiologic and environmental investigations of the cluster were initiated on July 26, including food history interviews of four patients. Three patients reported eating hog head cheese (a meat jelly made from swine heads and feet); the product was purchased at two grocery stores in Louisiana. A traceback investigation determined that a single brand of hog head cheese was common between the two grocery stores. L. monocytogenes serotype 1/2a was cultured from one of three product samples and from two of 16 environmental samples collected by LDAF at the processing establishment; the product and one of the two environmental samples yielded isolates with PFGE pattern combinations that were indistinguishable from the patient isolates. On August 14, LDAF coordinated a voluntary recall of approximately 500,000 pounds of hog head cheese and sausage because of possible contamination with L. monocytogenes. This is the first published report of an invasive listeriosis outbreak associated with hog head cheese, which is a ready-to-eat (RTE) meat. USDA-FSIS has a “zero tolerance” policy for L. monocytogenes contamination of RTE food products (1), requesting recall of such products at any detectable level of L. monocytogenes contamination. LDAF imposes and enforces equivalent requirements in state-inspected establishments.
Eight patients had illnesses that met the case definition. Their median age was 64 years (range: 38–93 years). Six patients were men; no patients were pregnant. Six patients had one or more underlying medical conditions (i.e., human immunodeficiency virus [HIV] infection, alcohol abuse, cancer, and diabetes mellitus). Illness onsets occurred from February 18 to June 16. Signs and symptoms included fever (n = 6 patients), altered mental status (n = 3), diarrhea (n = 3), vomiting (n = 3), and weakness (n = 2). Seven patients were hospitalized; two patients died.
In August of 2010, I reported about Veron Foods, LLC of Prairieville, Louisiana recalling approximately 500,000 pounds of “ready to eat” sausage and hog head cheese products that may be contaminated with Listeria monocytogenes. The following products were subject to recall:
All packages of Veron Hot Smoked Sausage, Veron Mild Smoked Sausage, Martin Hot Smoked Sausage, Martin Mild Smoked Sausage, Veron Andouille Sausage, Martin Andouille Sausage and Veron Hog Head Cheese. The products subject to recall bear the establishment number “LA 22” inside the LDAF mark of inspection as well as date codes of 010110 through 111310 and were distributed to retail establishments and institutions within the state of Louisiana. The State Report from 2010 is here.