Biological Activity of Extracts from Aromatic Plants as Control Agents against Spoilage Molds Isolated from Sheep Cheese.

Nuria Muñoz-Tebar,Emilio J González-Navarro,Gonzalo Ortiz De Elguea-Culebras,M Mercedes García-Martínez,María Isabel Berruga,Ana Molina,Teresa María López-Díaz,Jesús A Santos,Manuel Carmona

doi:10.3390/foods10071576

Nuria Muñoz-Tebar, Emilio J González-Navarro + Show 7 more

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https://doi.org/10.3390/foods10071576

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Abstract

The aim of this work was to assess the antifungal and antioxidant activity of essential oils and ethanolic extracts from distilled solid by-products from aromatic plants (Artemisia dracunculus, Hyssopus officinalis, Lavandula stoechas, Origanum vulgare and Satureja montana) against 14 fungi strains isolated from sheep cheese and identified at species level using DNA barcoding based on β-tubulin sequence analysis. In addition, capacity of fungi to produce ochratoxin A, patulin, cyclopiazonic acid and sterigmatocystin was analyzed. Of the isolates, 85.7% belonged to Penicillium (P. commune/biforme, P. crustosum) and 14.3% to Aspergillus (A. puulaauensis and A. jensenii), the first time that these Aspergillus species have been found in sheep’s cheese. All P. commune isolates were producers of cyclopiazonic acid, and the two Aspergillus strains produced sterigmatocystin, but the others did not produce any tested mycotoxin. Among the essential oils tested, oregano, savory and tarragon had a significant antifungal activity against all the isolated strains, but no ethanolic extract showed antifungal activity. By contrast, ethanolic extracts showed great potential as antioxidants. The identification of new molds in cheese will help the dairy industry to know more about those molds affecting the sector, and the use of aromatic plants in the control of fungal spoilage could be a suitable alternative to chemical preservatives used in the agri-food industry.

Highlights

Molds are one of the main microorganisms that cause food spoilage and their control is one of the major concerns for the food industry since they are responsible for significant economic losses [1,2]
The molecular identification of the mold strains isolated from sheep cheese reported the presence of two species of Aspergillus (A. jensenii and A. puulaauensis) never found in sheep cheeses, that showed the ability to produce sterigmatocystin, but at a level inferior to 50 μg/mL
The control of spoilage molds plays a key role in the dairy industry, so the findings of the present study will contribute to the identification and characterization of the sheep cheeses’ fungi, allowing more effective control measures, in order to secure the safety of consumers and reduce economic losses

Summary

Introduction

Molds are one of the main microorganisms that cause food spoilage and their control is one of the major concerns for the food industry since they are responsible for significant economic losses [1,2]. The mycotoxins produced by some types of molds are potentially toxic and can cause serious problems related to food safety [3,4] In this sense, cheese can be considered as a good substrate for many fungi species and its ripening and storage make this dairy product even more susceptible to growth and fungal contamination. There are other less common molds such as Alternaria, Fusarium, Geotrichum and Mucor that can cause several surface defects in cheese [12] For this reason, the identification of the mycobiota that affects cheeses plays a key role in food safety and can help the dairy industry improve control measures against these fungi

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