Survival of Escherichia coli on lettuce under field conditions encountered in the Northeastern United States

Daniel L. Weller, Jasna Kovac, Sherry Roof, David J. Kent, Jeffrey I. Tokman, Barbara Kowalcyk, David Oryang, Renata Ivanek, Anna Aceituno, Christopher Sroka, Martin Wiedmann

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Although wildlife intrusion and untreated manure have been associated with microbial contamination of produce, relatively few studies have examined the survival of Escherichia coli on produce under field conditions following contamination (e.g., via splash from wildlife feces). This experimental study was performed to estimate the die-off rate of E. coli on preharvest lettuce following contamination with a fecal slurry. During August 2015, field-grown lettuce was inoculated via pipette with a fecal slurry that was spiked with a three-strain cocktail of rifampin-resistant nonpathogenic E. coli. Ten lettuce heads were harvested at each of 13 time points following inoculation (0, 2.5, 5, and 24 h after inoculation and every 24 h thereafter until day 10). The most probable number (MPN) of E. coli on each lettuce head was determined, and die-off rates were estimated. The relationship between sample time and the log MPN of E. coli per head was modeled using a segmented linear model. This model had a breakpoint at 106 h (95% confidence interval=69, 142 h) after inoculation, with a daily decrease of 0.70 and 0.19 log MPN for 0 to 106 h and 106 to 240 h following inoculation, respectively. These findings are consistent with die-off rates obtained in similar studies that assessed E. coli survival on produce following irrigation. Overall, these findings provide die-off rates for E. coli on lettuce that can be used in future quantitative risk assessments.

Original languageEnglish (US)
Pages (from-to)1214-1221
Number of pages8
JournalJournal of Food Protection
Volume80
Issue number7
DOIs
StatePublished - Jul 1 2017

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Lettuce
New England
Northeastern United States
lettuce
die-off
Escherichia coli
head lettuce
wildlife
Head
quantitative risk assessment
rifampicin
Manure
microbial contamination
Rifampin
Feces
confidence interval
Linear Models
feces
linear models
irrigation

All Science Journal Classification (ASJC) codes

  • Food Science
  • Microbiology

Cite this

Weller, Daniel L. ; Kovac, Jasna ; Roof, Sherry ; Kent, David J. ; Tokman, Jeffrey I. ; Kowalcyk, Barbara ; Oryang, David ; Ivanek, Renata ; Aceituno, Anna ; Sroka, Christopher ; Wiedmann, Martin. / Survival of Escherichia coli on lettuce under field conditions encountered in the Northeastern United States. In: Journal of Food Protection. 2017 ; Vol. 80, No. 7. pp. 1214-1221.
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Weller, DL, Kovac, J, Roof, S, Kent, DJ, Tokman, JI, Kowalcyk, B, Oryang, D, Ivanek, R, Aceituno, A, Sroka, C & Wiedmann, M 2017, 'Survival of Escherichia coli on lettuce under field conditions encountered in the Northeastern United States', Journal of Food Protection, vol. 80, no. 7, pp. 1214-1221. https://doi.org/10.4315/0362-028X.JFP-16-419

Survival of Escherichia coli on lettuce under field conditions encountered in the Northeastern United States. / Weller, Daniel L.; Kovac, Jasna; Roof, Sherry; Kent, David J.; Tokman, Jeffrey I.; Kowalcyk, Barbara; Oryang, David; Ivanek, Renata; Aceituno, Anna; Sroka, Christopher; Wiedmann, Martin.

In: Journal of Food Protection, Vol. 80, No. 7, 01.07.2017, p. 1214-1221.

Research output: Contribution to journalArticle

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