Emergence of Leuconostoc mesenteroides as a causative agent of oozing in carrots stored under non-ventilated conditions

Yael Lampert, Barak Dror, Noa Sela, Paula Teper-Bamnolker, Avinoam Daus, Shlomo Sela (Saldinger), Dani Eshel

Research output: Contribution to journalArticlepeer-review

Abstract

Long-term storage and transport of post-harvest carrots (Daucus carota L.) require a low-temperature, high-relative-humidity environment, usually with low ventilation. Following long-term storage, a slimy exudate (oozing) often appears on the carrots, leading to severe spoilage. We characterized the environmental conditions leading to these symptoms and identified the causative agent. Simulation of non-ventilated storage conditions revealed accumulation of CO2 (to 80%) and ethanol (to 1000 ppm); then, a transparent exudate appeared on the carrot surface which, upon ventilation, developed into tissue browning and soft rot. Peels from oozing carrots contained over 10-fold the total bacterial counts of healthy carrots. The total peel microbiome was determined by 16S rDNA sequencing. During oozing stage, the surface of carrots incubated in a CO2-rich (98%) environment harboured a bacterial population dominated by Lactobacillales and Enterobacteriales, differing markedly from those incubated in air. Three prevalent bacterial isolates from the oozing carrots were identified as Pantoea agglomerans, Rahnella aquatilis and Leuconostoc mesenteroides. Inoculation of carrot discs with L. mesenteroides, but not the others, induced oozing under high CO2, suggesting that this bacterium is responsible for oozing of stored carrots. These findings should enable development of approaches to preventing carrot spoilage during long-term storage.

Original languageEnglish
Pages (from-to)1677-1689
Number of pages13
JournalMicrobial Biotechnology
Volume10
Issue number6
DOIs
StatePublished - Nov 2017
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Bioengineering
  • Biochemistry
  • Biotechnology

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