On May 5, 2010, the Athens City County Health Department (ACCHD) received notification of four patients admitted to the local hospital in the preceding 24 hours with nausea, vomiting, and diarrhea. All patients had reported eating at the same local Mexican food restaurant, Casa Lopez.
Later that day, health officials descended upon Casa Lopez to inspect the entire facility and observed several critical violations: (1) hot holding and cold holding conditions were conducive for the growth of bacteria; (2) improper use of single-use gloves; (3) soap was not available at hand wash only sink; (4) there was no date-markings on any food products in storage; and (5) raw food product was stored above uncovered chiles rellenos and other ready-to-eat foods in the walk-in freezer.
The ACCHD conducted follow-up inspections on May 6, 7, 12, and 17. On May 6, there were two improper cold holding temperatures. On May 7, there was an improper hot holding temperature, three improper cold holding temperatures, and no towels in the employee restroom. On May 12, one of the same cold holding violations from the previous visit had not been fixed, and ACCHD found a thawed, open container of egg whites. Finally, on May 17, no more violations were observed.
Public health investigators identified a total of 41 culture-confirmed cases of Salmonella serotype Enteritidis. An additional 14 case-patients who were not laboratory confirmed but were epidemiologically linked to the Casa Lopez restaurant were classified as either “probable” or “suspected” cases. Further testing by the Centers for Disease Control and Prevention revealed that 38 records matched exactly by multiple-locus variable number tandem repeat analysis (MLVA), allele typing, and PFGE.
Food history interviews revealed a strong association (p-value = 0.0002) between eating chiles rellenos with becoming ill with Salmonella Enteritidis. Additionally, one leftover meal tested positive for Salmonella, and was an identical match to the 38 specimens that were part of the outbreak and the case patient who submitted the leftover meal.