ATLANTA – ASalmonellaEnteritidis outbreak linked to food truck vendors highlights the importance of robust food-safety oversight of mobile kitchens and their food suppliers, according to a report in the Morbidity and Mortality Weekly Report released by the Atlanta-based Centers for Disease Control and Prevention.

The report follows an investigation into 91 SE infections in Calgary, Edmonton and southern Alberta, Canada. Six patients were hospitalized in connection with the outbreak, which occurred during October 2010 and February 2011. Food items most commonly identified among the affected customers were breakfast egg sandwiches and pork dumplings.

Public health officials with Alberta Health Services found 54 lunch trucks and targeted them for inspection. Several violations were uncovered, including selling foods from unlicensed food facilities and inadequate reheating of previously cooked food.

Seven Calgary-based caterers were identified as suppliers to the food trucks. During their investigations of the caterers, public health officials found that eggs at several facilities were cracked, visibly dirty and/or improperly packaged. These findings prompted a concurrent investigation of the egg suppliers; but continued traceback of food items revealed one caterer as the source of the SE illnesses.

"A bucket used for mixing pooled eggs by the implicated caterer during preparation of breakfast sandwiches had not been cleaned for several weeks and was stored in a cooler between uses," according to the report. "Pork dumplings sold by lunch trucks were produced by a Calgary-based manufacturer, and approximately 1,000 were distributed uncooked and frozen to several caterers each day."

The dumplings were cooked, packaged and refrigerated before distribution to the food trucks. Eggs were not an ingredient in the dumplings, and public health officials deemed adequate the cooking procedures used by the implicated caterer. However, pork dumplings and a sample of raw egg mixture from the egg bucket tested positive for SE at the implicated catering facility, the report states. Public health officials found sanitation, food handling and employee hygiene violations.

Employees of the caterer were screened forSalmonella, and six of 14 employees tested positive for SE, the report states. The infected employees were excluded from food-handling duties until they were non-infectious. Additional interventions included on-site safe food handling training, a thorough cleaning and disinfection of the catering facility and equipment; and implementation of an approved food safety plant developed by a third-party consultant. Despite the interventions, the caterer was ultimately prosecuted for using illegally sourced eggs.

Also, an illegal egg supplier was revealed as a result of the outbreak investigation.

"Several thousand eggs were seized from the supplier, and subsequent enforcement actions resulted in seizure of an egg delivery vehicle, issuance of a $2,500 fine and incarceration of the supplier for 14 days," the report stated.