Microbiological and Physicochemical Properties of Meat Coated with Microencapsulated Mexican Oregano (Lippia graveolens Kunth) and Basil (Ocimum basilicum L.) Essential Oils Mixture

Elvia Hernández-Hernández,Areli J Silva-Dávila,Jorge N Gracida-Rodríguez,Blanca E García-Almendárez,Carlos Regalado-González,Prospero Di Pierro,Claudia J González-Gutiérrez,Gustavo Castillo-Hernández,Pedro Vázquez-Landaverde

doi:10.3390/coatings9070414

Abstract

Microencapsulated essential oils (EOs) are increasingly used to protect the safety of foods due to their natural origin. The aim of this work was to determine the chemical composition of Mexican oregano (Lippia graveolens Kunth) (MOEO) and basil (Ocimum basilicum L.) (BEO) EOs, their combined effect against E. coli O157:H7, Lactobacillus plantarum, Brochothrix thermosphacta and Pseudomonas fragi, and their effect on microbiological and physicochemical properties of coated pork meat. EOs chemical composition was determined by GC/MS, their microencapsulated mixture (4 mg MOEO/mL/11 mg BEO/mL) was added to a filmogenic dispersion. Fluorescent probes were used to study the antimicrobial filmogenic active dispersion (FD) effect. Pork meat pieces were coated without microencapsulated EOs (CC), using FD (AC), or uncoated (C), vacuum packed and stored 28 days at 4 °C. Thymol (28.9%) and linalool (23.7%) were the major components of MOEO and BEO, respectively. The cell membrane of all bacteria was damaged by contact with FD. FD-coated samples (AC) exhibited the lowest concentration of 2-thiobarbituric acid reacting substances (TBARS) (0.027 ± 0.001 mg malonaldehyde/kg meat) and natural microbiota growth, while odor and color were the most accepted by untrained judges (range > 6). Coatings added with microencapsulated EOs mixture are a natural food preservation alternative to increase the shelf life of refrigerated meat products.

Highlights

Fresh meat is a good source of nutrients and is a complex matrix where food-borne pathogens and spoilage microorganisms can grow [1,2,3]
essential oils (EOs) are low molecular weight volatile mixtures that are biosynthesized in various organs of plants, the biological activity is determined by their chemical composition that depends on several factors like extraction method [9], climatic and geographical conditions, [7] and genetic diversity [10]
The antimicrobial effect of Mexican oregano essential oil (MOEO) and basil essential oil (BEO), and their components applied individually or in combination has been evaluated against food-borne pathogens

Summary

Introduction

Fresh meat is a good source of nutrients and is a complex matrix where food-borne pathogens and spoilage microorganisms can grow [1,2,3]. To extend the shelf life and ensure the safety of these products refrigerated storage under vacuum or modified atmosphere packaging are used These conditions allow survival and growth of pathogens and spoilage strains, as well as the Coatings 2019, 9, 414; doi:10.3390/coatings9070414 www.mdpi.com/journal/coatings. Coatings 2019, 9, 414 development of oxidation reactions [1,2,4] To decrease this problem, bioactive edible film-forming suspensions (FD) can be applied on fresh meat as a coating [5] containing EOs obtained from plants such as basil and oregano [2,4,6,7,8]. EO combinations increase the number of active compounds and diversity, and extend the mechanisms of action leading to the application of low EOs concentrations to achieve control of microbial growth and lipids oxidation. No reports were found about the combination of MOEO and BEO

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