Wednesday, December 21, 2016

C. perfrigens Identified as Cause of Thanksgiving Foodborne Illness Outbreak

Shortly after Thanksgiving, an outbreak of foodborne illness was reported in California that was linked to a Thanksgiving charity event.  There were 3 deaths and another 22 others who were ill.  The causative agent was found to be Clostridium perfringens, a sporeforming pathogen that can grow rapidly when food is temperature abused.

The actual food source of the bacteria was not found, however investigators "found most of the ill people ate turkey and mashed potatoes and they all ate around the same time. Some dishes served at the event, including cooked turkey, were brought to the site after they were prepared in private homes."

A similar scenario occurred in a 2015 outbreak linked to a Thanksgiving luncheon.  In this case, 40 became ill from food contaminated with Clostridium perfrigens.  In this case however, food was prepared by a caterer.

Clostridium perfrigens
  • Is a gram positive sporeforming anaerobe.
  • Is widely distributed in the environment, but can be found in the intestines of animals and humans (but in small numbers).
  • Spores are heat resistant and can survive boiling temperatures.  (Dvalues at 100C can range from 0.31min to 17.5min),
  • In heat-treated foods that are temperature abused, this organism can divide in as fast as every 10 minutes.  (The heat treatment eliminates any competitive flora.)  Common food sources include cooked meat foods such as stews and casseroles that are temperature abused.
  • Symptoms are caused by ingestion of large numbers ( > 106) vegetative cells or >106 spores/g of food. Toxin production in the digestive tract (or in vitro) is associated with sporulation.  This usually occurs about 16 hours after ingestion.  As the organism numbers increase, it produces an enterotoxin, and this entertoxin is responsible for the illness
  • The primary symptoms are cramping and diarrhea and usually dissipate within 24 hours.
The cooling procedures in the Food Code and Appendix B for USDA are established taking C. perfringens into account.

This event points out the risk of having volunteers prepare food in their own home.  In many cases, these people have not been trained in preparing large quantities of food and/or preparing food for events outside of their own home.  In the latter, food transportation can be an issue, especially in warmer areas like California.

CBS SF Bay Area News
Common Bacteria Caused Antioch Thanksgiving Dinner Deaths
December 20, 2016 11:43 AM

ANTIOCH (CBS SF) — A common food-borne bacteria was responsible for three deaths and the illnesses suffered by 22 others following a Thanksgiving meal sponsored by a community church at Antioch’s American Legion auditorium, health officials announced Tuesday.

Contra Costa County health officials said a laboratory at the U.S. Centers for Disease Control & Prevention confirmed the presence of the bacteria — Clostridium perfringens — in stool samples taken from people sickened by food.

“Clostridium perfringens is one of the most common foodborne illnesses in the U.S.,” said Dr. Louise McNitt, deputy health officer for Contra Costa Health Services in a news release. “It can be found in the human intestine without hurting us, but eating food containing large amounts of this bacteria can cause illness and in some cases death."

Dr. Marilyn Underwood said while the bacteria was identified, it was not determined which dish contained it.

“Our investigation was not able to determine exactly what people ate that made them sick,” she said. “But after extensive interviews we found most of the ill people ate turkey and mashed potatoes and they all ate around the same time. Some dishes served at the event, including cooked turkey, were brought to the site after they were prepared in private homes.”

Underwood said proper food handling was essential to prevent foodborne illness, including cooking foods to proper temperatures, cooling and storing them appropriately if they’re not going to be eaten right away, separating raw meats from foods that won’t be cooked, storing food properly and washing hands and cooking surfaces often.

“We’re saddened for the families that suffered losses this holiday season,” she said. “We encourage anyone planning charity events where food will be served to the public to contact us to understand the permitting process and to learn about food safety.”

The coroner’s office identified the victims as 43-year old Christopher Cappetti, 59-year-old Chooi Keng Cheah and 69-year-old Jane Evans. All three were residents at assisted living facilities in Antioch who were served food at the Thanksgiving Day event.

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