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Research article - Peer-reviewed, 2023

Volatilomes reveal specific signatures for contamination of leafy vegetables with Escherichia coli O157:H7

Sousa, Maria; Mulaosmanovic, Emina; Erdei, Anna Laura; Bengtsson, Marie; Witzgall, Peter; Alsanius, Beatrix W.

Abstract

Transmission of foodborne pathogens by plants, especially shiga toxin-producing Escherichia coli, has become a public health concern for ready-to-eat products. Due to the patchy distribution of foodborne pathogens on commodities, random sampling before processing and following packaging cannot reliably exclude presence of pathogenic microbes. Robust, cost-effective, and reliable methods for monitoring pathogenic E. coli on fresh produce are therefore urgently needed. We investigated whether volatile organic compounds are suitable for detection of E. coli O157:H7 contamination of leafy vegetables. Using solid-phase microextraction coupled with gas chromatography-mass spectrometry, we analyzed volatilomes of spinach (Spinacia oleracea L.) and rocket (Eruca sativa L.) leaf lysates, and of a common culture medium (lysogeny broth), in the presence and absence of E. coli O157:H7. Volatile profiles varied with the nutrient medium. We found higher proportions of indole, phenylmethanol, 2-methoxyphenol, ethanol, propan-1-ol, decan-1-ol, tridecan-1-ol, nonan-2-one and tridecan-2-one in headspace from inoculated compared with non-inoculated samples. This demonstrates that volatile organic compounds are suitable for detecting contamination of leafy vegetables with E. coli O157:H7. In future work we will focus on adapting the volatile assay for screening for E. coli O157:H7 contamination under different conditions, including intact and damaged baby leaves, leaf packages, or leaf batches, and on increasing its sensitivity.

Keywords

foodborne pathogens; headspace; leafy vegetables; rocket(Eruca sativa L; ); spinach(Spinacia oleracea L; volatilome; (E)-hex-2-enal; indole

Published in

Food Control
2023, volume: 146, article number: 109513
Publisher: ELSEVIER SCI LTD

Authors' information

Swedish University of Agricultural Sciences, Department of Biosystems and Technology
Swedish University of Agricultural Sciences, Department of Plant Protection Biology
Mulaosmanovic, Emina
Swedish University of Agricultural Sciences, Department of Biosystems and Technology
Swedish University of Agricultural Sciences, Department of Plant Protection Biology
Hungarian Centre for Agricultural Research
Swedish University of Agricultural Sciences, Department of Plant Protection Biology
Swedish University of Agricultural Sciences, Department of Plant Protection Biology
Swedish University of Agricultural Sciences, Department of Biosystems and Technology

UKÄ Subject classification

Food Science

Publication Identifiers

DOI: https://doi.org/10.1016/j.foodcont.2022.109513

URI (permanent link to this page)

https://res.slu.se/id/publ/120684