Vacuolar localisation of anthocyanin pigmentation in microgreen cotyledons of basil, cabbage and mustard greens does not impact on colonisation by Shiga-toxigenic Escherichia coli O157:H7

Microgreens, the immature plants harvested after a few weeks of growth, are perceived as a heathy, nutritious food ingredient but may be susceptible to col

Kathryn M. Wright, J. Marshall, Peter J. Wright, Nicola Holden

Food Microbiology · 2023 · https://doi.org/10.1016/j.fm.2023.104367

Abstract

Microgreens, the immature plants harvested after a few weeks of growth, are perceived as a heathy, nutritious food ingredient but may be susceptible to colonisation by human pathogens including Shiga-toxigenic Escherichia coli (STEC). Some microgreen cultivars accumulate anthocyanins or secrete essential oils which, when extracted or purified, have been reported to inhibit bacterial growth. Therefore, the impact of anthocyanins on bacterial colonisation by STEC (Sakai) was compared for three species that have pigmented cultivars: basil (Ocimum basilicum L.), cabbage (Brassica oleracea L.) and mustard greens (Brassica juncea L.). Inoculation with low concentrations of STEC (Sakai) (3 log10 colony forming units/ml (CFU/ml)) during seed germination resulted in extensive colonisation at the point of harvest, accumulating to ∼ 8 log10 CFU/g FW in all cultivars. Bacterial colonies frequently aligned with anticlinal walls on the surface of epidermal cells of the cotyledons and, in basil, associated with peltate and capitate gland cells. Crude lysates of pigmented and non-pigmented basil cultivars had no impact on STEC (Sakai) growth rates, viability status or biofilm formation. Anthocyanins are located within plant vacuoles of these microgreen cultivars and did not affect colonisation by STEC (Sakai) and pigmentation therefore cannot be considered as a controlling factor in bacterial interactions.

Licence and reuse

LicenceCC-BY-4.0
May we host this PDF?Yes
May we publish a plain-language summary?Yes — this licence permits adaptations.
Commercial use permitted?Yes
Share-alike required?No

How to credit this work

Kathryn M. Wright; J. Marshall; Peter J. Wright; Nicola Holden (2023). Vacuolar localisation of anthocyanin pigmentation in microgreen cotyledons of basil, cabbage and mustard greens does not impact on colonisation by Shiga-toxigenic Escherichia coli O157:H7. Food Microbiology. https://doi.org/10.1016/j.fm.2023.104367 Licensed under Creative Commons Attribution 4.0 (https://creativecommons.org/licenses/by/4.0/). Hosted by EVEC Athens (microgreens.org.gr). No changes were made to this article. Provided as-is, without warranties. EVEC Athens is not affiliated with, and this copy is not endorsed by, the authors or the publisher.

Explore this on our site

About this copy

This is a copy of the published article, hosted by EVEC Athens for free educational use under its open licence. The permanent scientific reference is the DOI above. We have not altered the file in any way. If you are an author or rights holder and want this copy removed, please use our notice and takedown procedure. We acknowledge every request within five working days, and act within ten.

Co-funded by the European Union.
This portal presents the microgreens methodology; the organisation behind it is EVEC Athens — the European Voluntary and Educational Center (evec.org.gr). Views and opinions expressed are those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the granting authority can be held responsible for them.

Open licence. Except where stated otherwise, the educational materials on this portal are licensed under CC BY 4.0 — free to use, adapt and share, including commercially, with credit. See the licence terms.

Accessibility. We aim for WCAG 2.1 AA and publish what does and does not yet meet it — see the accessibility statement. If anything here blocks you, tell us and we will send the material in a format that works for you.