Identification of fungal metabolites from inside Gallus gallus domesticus eggshells by non-invasively detecting volatile organic compounds (VOCs) - PubMed (original) (raw)

Identification of fungal metabolites from inside Gallus gallus domesticus eggshells by non-invasively detecting volatile organic compounds (VOCs)

Raquel Cumeras et al. Anal Bioanal Chem. 2016 Sep.

Abstract

The natural porosity of eggshells allows hen eggs to become contaminated with microbes from the nesting material and environment. Those microorganisms can later proliferate due to the humid ambient conditions while stored in refrigerators, causing a potential health hazard to the consumer. The microbes' volatile organic compounds (mVOCs) are released by both fungi and bacteria. We studied mVOCs produced by aging eggs likely contaminated by fungi and fresh eggs using the non-invasive detection method of gas-phase sampling of volatiles followed by gas chromatography/mass spectrometry (GC/MS) analysis. Two different fungal species (Cladosporium macrocarpum and Botrytis cinerea) and two different bacteria species (Stenotrophomas rhizophila and Pseudomonas argentinensis) were identified inside the studied eggs. Two compounds believed to originate from the fungi themselves were identified. One fungus-specific compound was found in both egg and the fungi: trichloromethane. Graphical abstract Trichloromethane is a potential biomarker of fungal contamination of eggs.

Keywords: Bacteria; Fungi; Gas chromatography/mass spectrometry (GC/MS); Hen egg; Solid-phase microextraction (SPME); Volatile organic compounds (VOCs).

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Figure 1

Figure 1

Fungi found inside a hen eggshell.

Figure 2

Figure 2

Schematic representation of the headspace (HS) sampling methodologies with SPME used with A) eggs inside a vial and B) fungi isolates grown on 9 cm-diameter Petri dishes.

Figure 3

Figure 3

Representative chromatograms of two analyzed eggs, egg 2 (fungi) and egg 5 (fresh). A zoomed portion of the chromatogram (insert) shows the identified trichloromethane peak for the fungi egg.

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