Alfalfa sprouts and Salmonella Kottbus infection: A multistate outbreak following inadequate seed disinfection with heat and chlorine

Kevin Winthrop, M. S. Palumbo, J. A. Farrar, J. C. Mohle-Boetani, S. Abbott, M. E. Beatty, G. Inami, S. B. Werner

Research output: Contribution to journalArticle

68 Citations (Scopus)

Abstract

Raw sprouts have been implicated in a number of foodborne disease outbreaks. Because contaminated seeds are usually responsible, many sprout producers attempt to disinfect seeds before germination and detect sprout contamination during production. In March 2001, we detected an increased number of Salmonella serotype Kottbus isolates in California. Overall, we identified 31 cases from three western states. To identify the cause, we conducted a case-control study with the first 10 identified case-patients matched to 20 controls by age, sex, and residential area. Our case-control study found illness to be statistically associated with alfalfa sprout consumption. The traceback investigation implicated a single sprouter, where environmental studies yielded Salmonella Kottbus from ungerminated seeds and floor drains within the production facility. Pulsed-field gel electrophoresis patterns of all patient, seed, and floor drain Salmonella Kottbus isolates were indistinguishable. Most implicated sprouts were from seeds that underwent heat treatment and soaking with a 2,000-ppm sodium hypochlorite solution rather than the Food and Drug Administration (FDA)-recommended 20,000-ppm calcium hypochlorite soak. Other implicated seeds had been soaked in a calcium hypochlorite solution that, when tested, measured only 11,000 ppm. The outbreak might have been averted when screening tests of sprout irrigation water detected Salmonella in January; however, confirmatory testing of these samples was negative (but testing improperly utilized refrigerated irrigation water). Producers should use the enrichment broth of positive screening samples, not refrigerated irrigation water, for confirmatory testing. Until other effective disinfection technologies are developed, producers should adhere to FDA recommendations for sprout seed disinfection.

Original languageEnglish (US)
Pages (from-to)13-17
Number of pages5
JournalJournal of Food Protection
Volume66
Issue number1
StatePublished - Jan 1 2003
Externally publishedYes

Fingerprint

Salmonella Kottbus
Medicago sativa
Salmonella Infections
Chlorine
Disinfection
disinfection
chlorine
Disease Outbreaks
alfalfa
Seeds
Hot Temperature
heat
Salmonella
seeds
calcium hypochlorite
infection
irrigation water
case-control studies
United States Food and Drug Administration
Water

ASJC Scopus subject areas

  • Food Science
  • Applied Microbiology and Biotechnology
  • Biotechnology

Cite this

Winthrop, K., Palumbo, M. S., Farrar, J. A., Mohle-Boetani, J. C., Abbott, S., Beatty, M. E., ... Werner, S. B. (2003). Alfalfa sprouts and Salmonella Kottbus infection: A multistate outbreak following inadequate seed disinfection with heat and chlorine. Journal of Food Protection, 66(1), 13-17.

Alfalfa sprouts and Salmonella Kottbus infection : A multistate outbreak following inadequate seed disinfection with heat and chlorine. / Winthrop, Kevin; Palumbo, M. S.; Farrar, J. A.; Mohle-Boetani, J. C.; Abbott, S.; Beatty, M. E.; Inami, G.; Werner, S. B.

In: Journal of Food Protection, Vol. 66, No. 1, 01.01.2003, p. 13-17.

Research output: Contribution to journalArticle

Winthrop, K, Palumbo, MS, Farrar, JA, Mohle-Boetani, JC, Abbott, S, Beatty, ME, Inami, G & Werner, SB 2003, 'Alfalfa sprouts and Salmonella Kottbus infection: A multistate outbreak following inadequate seed disinfection with heat and chlorine', Journal of Food Protection, vol. 66, no. 1, pp. 13-17.
Winthrop, Kevin ; Palumbo, M. S. ; Farrar, J. A. ; Mohle-Boetani, J. C. ; Abbott, S. ; Beatty, M. E. ; Inami, G. ; Werner, S. B. / Alfalfa sprouts and Salmonella Kottbus infection : A multistate outbreak following inadequate seed disinfection with heat and chlorine. In: Journal of Food Protection. 2003 ; Vol. 66, No. 1. pp. 13-17.
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