Prevention strategies include rigorous Salmonella control and education should be at the wholesaler and restaurant level.
They added best practices in all parts of the pork production industry, from farm to processing plant, can also help reduce the risk for future outbreaks.
Kapowsin Meats was linked to the outbreak and it recalled products before voluntarily suspending operations in August last year.
Illnesses from 5 states, mostly Washington
A total of 192 confirmed cases were reported from five states; 184 in Washington. Patients ranged in age from <1 to 90 years and 97 were female.
Among 180 patients for whom information about hospitalization was available, 30 were hospitalized; no deaths were reported.
Among 80 patients (42% of all confirmed cases) who were interviewed, 59 reported eating pork during the seven days before illness.
This was significantly higher than the 2007 Foodborne Diseases Active Surveillance Network (FoodNet) population survey of healthy people, in which 43% ate pork in the week before they were interviewed.
Public Health–Seattle & King County (PHSKC) and Washington State Department of Health (WADOH) investigated 22 clusters of Salmonella serotype I 4,, 12:i:- infections.
WADOH and PHSKC traced the pork eaten by 35 (59%) of 59 interviewed patients back to a US Department of Agriculture’s Food Safety and Inspection Service–inspected pork slaughter plant in Graham, Washington.
During the outbreak period, Kapowsin Meats distributed whole hogs and pork parts from five farms in Montana and one in Washington, to Washington, Oregon, and Alaska.
Among the 21 interviewed patients who did not eat pork before becoming ill, 13 had eaten at one of two restaurants or had shopped at one market where pork from the firm was served.
Outbreak strains found in facility
During June and July 2015, PHSKC inspections of these three facilities identified potential opportunities for cross-contamination of raw pork with other meat and produce, including inadequate employee handwashing and insufficient cleaning and sanitization of food contact surfaces and utensils used for raw meat.
Food and environmental sampling by PHSKC at the facilities yielded the outbreak strains.
Eight of 11 environmental samples collected from the slaughter establishment by WADOH yielded one of the outbreak strains.
A Food Safety and Inspection Service investigation cited unsanitary conditions, supported by isolation of outbreak strains from samples taken before the start of daily operations, consistent with WADOH results.
The agency deemed sanitary improvement efforts made by Kapowsin Meats insufficient.
FSIS isolated Salmonella Infantis which was added to the case definition and four patients were identified.
In August 2015, the establishment recalled an estimated 116,262 pounds of whole hogs produced during April 18–July 27, and later that month expanded it to include 523,380 pounds of pork produced during April 18–August 26 before ceasing operations.
Ten clinical isolates of the outbreak strains from Washington were submitted to CDC’s National Antimicrobial Resistance Monitoring System for resistance testing. All 10 exhibited resistance to ampicillin, streptomycin, sulfisoxazole, and tetracycline (ASSuT resistance).
Source: MMWR Morb Mortal Wkly Rep 2016; 65:379–381
“Outbreak of Multidrug-Resistant Salmonella Infections Linked to Pork — Washington, 2015”
Authors: Kawakami VM, Bottichio L, Angelo K, et al.