Zn, Cu, and Fe Concentrations in Dehydrated Herbs (Thyme, Rosemary, Cloves, Oregano, and Basil) and the Correlation with the Microbial Counts of Listeria monocytogenes and Other Foodborne Pathogens.

José María García-Galdeano,Jessandra Gabriela Zamora-Bustillos,Miguel Navarro-Alarcón,Ahmad Agil,José Medina-Martínez,Lydia María Vázquez-Foronda,Marina Villalón-Mir,Sofía María Fonseca Moor-Davie

doi:10.3390/foods9111658

José María García-Galdeano, Jessandra Gabriela Zamora-Bustillos + Show 6 more

Open Access

https://doi.org/10.3390/foods9111658

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Journal: Foods (Basel, Switzerland)	Publication Date: Nov 12, 2020
Citations: 6	License type: CC BY 4.0

Affiliation: University of Granada

Abstract

Zn, Cu, and Fe concentrations were measured in dehydrated herbs (thyme, rosemary, cloves, oregano, and basil) marketed in bulk or packaged in glass or polyethylene terephthalate (PET). Microbial counts of Listeria monocytogenes and other five foodborne pathogens were also checked when herbs were previously added to the growing media. The highest mean concentrations were found in basil for Zn and Cu, and in thyme and basil for Fe; the lowest ones for these minerals were in cloves (p < 0.05). Basil had significantly higher microbial counts in five of the six foodborne pathogens studied (p < 0.05). Cloves have the best hygienic quality as there is no microbial growth of L. monocytogenes, Clostridium perfringens, and Bacillus cereus; they therefore could be used as a natural preservative in food. Aromatic herbs marketed in bulk showed a significantly higher microbial count (p < 0.05). Zn, Cu, and Fe concentrations were positively correlated with microbial growth for L. monocytogenes, C. perfringens, B. cereus, and psychrophilic microorganisms (p < 0.05), so they could act as a growing factor for the foodborne pathogens.

Highlights

Aromatic herbs are minority components, as far as consumption is concerned, in the daily diet [1](1.5 g/day in European countries [2])
In relation to the hygienic quality of the samples analyzed, our study showed that the samples sold in bulk presented a high degree of contamination with respect to L. monocytogenes, B. cereus, psychrophilic and mesophilic microorganisms, and molds and yeasts, with thyme, rosemary, and basil presenting the highest levels of microbial contamination
The content of Zn, Cu, and Fe varies depending on the aromatic herb

Summary

Introduction

(1.5 g/day in European countries [2]) Their traditional use is associated with the seasoning of culinary preparations to facilitate desirable flavors, aromas, and/or colors, being the main determinants of the sensory quality of food [1,2]. Another extended use of these herbs, increasing the amount added to food, is the masking of undesirable flavors when they have been submitted to an inadequate state of preservation. Foods 2020, 9, 1658 extracts of rosemary at 1% in active packaging have been proposed as components of a protective film of biodegradable serum protein, as they present antimicrobial activity against L. monocytogenes [12].

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Discussion

Conclusion