Notes from the Field: Salmonella Newport Infections Associated with Consumption of Unpasteurized Milk --- Utah, April--June 2010

Notes from the Field: Salmonella Newport Infections Associated with Consumption of Unpasteurized Milk --- Utah, April--June 2010
Weekly
July 9, 2010 / 59(26);817-818


On April 29, 2010, the Utah Department of Health (UDOH) was notified of three cases of Salmonella enterica serotype Newport infection. The three patients recently had consumed unpasteurized milk purchased from a store in northern Utah (store A). In Utah, unpasteurized milk can be sold legally at licensed dairies or by licensed dairies at dairy-owned retail stores meeting specific requirements (1). A central Utah dairy licensed to sell unpasteurized milk (dairy A) owns and sells unpasteurized milk at store A and a second northern Utah store (store B). By May 3, 2010, three additional patients with S. Newport infections had been reported; all recently had consumed unpasteurized milk purchased from store A. UDOH notified the Utah Department of Agriculture and Food (UDAF) of the suspected association between illness and unpasteurized milk consumption, and UDAF suspended sales of unpasteurized milk at the two stores on May 3, 2010.

During April 29--June 3, 2010, a total of 10 S. Newport cases were reported to UDOH; all 10 patients had consumed unpasteurized milk from store A (seven patients) or store B (three patients). The patients ranged in age from 2 to 56 years (median: 21 years); six were female. One patient was hospitalized. Isolates from all 10 patients were identified as indistinguishable by two-enzyme pulsed-field gel electrophoresis (PFGE), with pattern combination UTJJPX01.098/UTJJPA26.009, and were sensitive to routinely used antibiotics. Cultures of frozen, unpasteurized milk samples stored at dairy A from batches of milk sold during the outbreak period yielded S. Newport isolates indistinguishable by PFGE from the outbreak strain. An inspection of dairy A on May 7, 2010, did not reveal any obvious sources of contamination.

On May 12, 2010, on the basis of coliform test results within legal limits, the dairy was permitted to resume sales of unpasteurized milk. Ongoing testing includes monthly screening for Salmonella spp. in retail samples of unpasteurized milk. As of June 21, 2010, no additional cases had been reported to UDOH. Consumption of unpasteurized dairy products poses a risk for foodborne illness (2), and consumers of unpasteurized milk should be aware of this risk.

Reported by
JM Hall, MPH, RT Rolfs, MD, RK Herlihy, MD, MPS Dimond, MPH, Bur of Epidemiology, Utah Dept of Health; J Holbrook, MPH, Utah County Health Dept; LH Smith, JM Wagner, Unified State Laboratories: Public Health, Utah Dept of Health; RW Clark, MPH, Utah Dept of Agriculture and Food. WA Lanier, DVM, EIS Officer, CDC.

References
1.Utah Dairy Act. Utah Code sec 4-3-14. Available at http://le.utah.gov/~code/TITLE04/htm/04_03_001400.htm. Accessed July 1, 2010.
2.Oliver SP, Boor KJ, Murphy SC, Murinda SE. Food safety hazards associated with consumption of raw milk. Foodborne Path Dis 2009;6:793--806.

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Notes from the Field: Salmonella Newport Infections Associated with Consumption of Unpasteurized Milk --- Utah, April--June 2010