Months after an E. coli outbreak sickened nine people at Huntley High School before being linked to a larger spread of the illness across 10 different U.S. states, health officials have determined the cause of the outbreak.
An investigation from the McHenry County Health Department concluded that the outbreak was likely caused by an infected food handler in the high school's cafeteria.
Health officials determined that a food worker who worked at the cookie station and handled garnishes, such as lettuce and cheese, for cold sandwiches was confirmed to have been intermittently shedding STEC, or Shigatoxigenic E. coli, by PCR test.
Though the food handler denied having any illness at the time of the outbreak, most infections resolve on their own without medical treatment, and since STEC can be shed for as long as 62 days, it is likely that the worker previously had a mild illness and did not associate it with the outbreak.
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All twelve food samples from the school that were tested returned negative results for E. coli bacteria, officials said. Additionally, no alert or recall related to food contaminated with STEC in Illinois was in effect during the time of the outbreak.
Investigators believe that the most likely cause of the outbreak was the food handler failing to properly wash their hands thoroughly or frequently enough, leading to STEC contaminating either surfaces such as trays and packaging or the food itself.
Without proper sanitization, STEC can remain present on surfaces for up to 16 months.
Additionally, the following violations were noted by investigators upon inspection of the cafeteria:
- The high heat sanitizing dish machine did not register the minimum required temperature (160 degrees F) to ensure the dishware and equipment were being sanitized.
- There were no established written procedures, as required, in order to utilize time as a public health control for time/temperature control for safety (TCS) foods (hot subs) that are held for service.
- TCS foods (hot subs) being held utilizing time as a public health control were not marked with the time that is 4 hours past the point in time when food is removed from temperature control. TCS foods past the 4-hour limit must be discarded.
- Two (2) HHS food handlers were observed failing to utilize a barrier to turn off the hand sink.
- One HHS food handler was observed preparing foods while wearing arm jewelry and a wristwatch.
A full view of the investigation's findings can be found here.
