Commercial wash of leafy vegetables do not significantly decrease bacterial load but leads to shifts in bacterial species composition

Abstract

Production of leafy vegetables for the "Ready-to-eat"-market has vastly increased the last 20 years, and consumption of these minimally processed vegetables has led to outbreaks of food-borne diseases. Contamination of leafy vegetables can occur throughout the production chain, and therefore washing of the produce has become a standard in commercial processing. This study explores the bacterial communities of spinach (Spinacia oleracea) and rocket (Diplotaxis tenuifolia) in a commercial setting in order to identify potential contamination events, and to investigate effects on bacterial load by commercial processing. Samples were taken in field, after washing of the produce and at the end of shelf-life. This study found that the bacterial community composition and diversity changed significantly from the first harvest to the end of shelf-life, where the core microbiome from the first to the last sampling constituted <2% of all OTUs. While washing of the produce had no reducing effect on bacterial load compared to unwashed, washing led to a change in species composition. As the leaves entered the cold chain after harvest, a rise was seen in the relative abundance of spoilage bacteria. E. coli was detected after the washing indicating issues of cross-contamination in the wash water.

Keywords

microbiome; minimally processed leafy vegetables; Phyllosphere spinach (Spinacia oleracea); Rocket (Diplotaxis tenuifolia)

Published in

Food Microbiology
2021, volume: 94, article number: 103667

SLU Authors

• Rosberg, Anna Karin

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    

• Darlison, Julia

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    

• Mogren, Lars

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    

• Alsanius, Beatrix

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    

Global goals (SDG)

SDG3 Good health and well-being

UKÄ Subject classification

Horticulture
Microbiology

Publication identifier

• DOI: https://doi.org/10.1016/j.fm.2020.103667

Permanent link to this page (URI)

https://res.slu.se/id/publ/109218