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The aim of the present work was the selection of aromatic plant essential oils (EOs) and/or ethanolic extracts (EEs) to prevent the late blowing defect (LBD) of cheese caused by Clostridium spp. EEs resulted more effective than EOs to inhibit dairy-borne Clostridium spp. in vitro. Savory, hyssop, lavender and tarragon EEs, which showed the lowest minimal inhibitory concentration against Clostridium tyrobutyricum, were selected to study the prevention of LBD caused by this bacterium in cheese. Addition of savory and lavender EEs to cheese milk delayed LBD by 2 weeks, but at the end of ripening these cheeses showed similar clostridial vegetative cells counts, spoilage symptoms and propionic, and butyric acids levels than blown control cheese. Tarragon EE, with the highest content in caffeic acid, also delayed LBD by 2 weeks, but it was more effective to inhibit Clostridium, since cheese with tarragon EE showed minor LBD symptoms, lower vegetative cells count and lower concentrations of propionic and butyric acids than the rest of cheeses made with EEs. This fact could be also attributable to the greater number of antimicrobial terpenes (1,8-cineole, 4-terpineol, α-terpineol, isoelemicin, methyl eugenol, and methyl trans-isoeugenol) detected in this cheese. This is the first report on the application of EEs to control C. tyrobutyricum in cheese., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The use of aromatic plant extracts as ingredients may be compromised owing to low transference and activity lack in food matrixes compared with in vitro trials. Rosemary essential oil (REO) was added to sheep milk to study the transference of its compounds during the cheese-making process and to determine how cheese antimicrobial activity is modified., Results: The volatile characterization of dairy samples was performed using headspace stir bar sorptive extraction coupled to gas chromatography/mass spectrometry (HS-SBSE/GC/MS) so that fat matrix interferences were reduced. This method detected a decrease in volatile recovery concentration of 19.33% when REO was added to milk. A total recovery volatile yield of 62.51% was measured from the initial quantification of milk to cheese, with hydrocarbon volatiles being transferred in a higher ratio (64.88%) than oxygenated ones (58.74%). No effects were observed for REO in fortified cheese on the counts of native flora necessary for ripening processes, but the total inhibition of Clostridium spp. was provoked, Conclusion: The study of active compound transference during cheese elaboration was achieved. The antimicrobial results in fortified cheeses with REO showed a preventive effect in the case of clostridial species, which are responsible for late cheese blowing., (© 2014 Society of Chemical Industry.)

Background: The use of aromatic plants and their extracts with antimicrobial properties may be compromised in the case of cheese, as some type of fungal starter is needed during its production. Penicillium verrucosum is considered a common cheese spoiler. The aim of this study was to evaluate the innovative use of certain aromatic plants as natural cheese covers in order to prevent mycotoxicogenic fungal growth (P. verrucosum). A collection of 12 essential oils (EOs) was obtained from various aromatic plants by solvent-free microwave extraction technology, and volatile characterisation of the EOs was carried out by gas chromatography/mass spectrometry., Results: The most effective EOs against P. verrucosum were obtained from Anethum graveolens, Hyssopus officinalis and Chamaemelum nobile, yielding 50% inhibition of fungal growth at concentration values lower than 0.02 µL mL⁻¹. All EOs showed high volatile heterogeneity, with α-phellandrene, pinocamphone, isopinocamphone, α-pinene, camphene, 1,8-cineole, carvacrol and trans-anethole being found to be statistically significant in the antifungal model., Conclusion: The use of these aromatic plants as natural covers on cheese can satisfactorily inhibit the growth of some mycotoxicogenic fungal spoilers. Among the volatile compounds present, α- and β-phellandrene were confirmed as the most relevant in the inhibition., (© 2012 Society of Chemical Industry.)

Saffron spice has been successfully used as an ingredient in dairy products as a means of diversification. The objective of this work was to determine the influence of saffron on the volatiles' profile of a pressed ewes' milk cheese. This was performed by means of a modern extraction technique based on headspace sorptive extraction. Results showed that safranal was the only volatile that could be identified and quantified from saffron spice. Most volatile compounds were present in all cheeses but at different concentrations. Differences between control and saffron cheeses were observed, but as ripening time increased, these differences were less evident. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

During the last decades, essential oils (EOs) have been proven to be a natural alternative to additives or pasteurization for the prevention of microbial spoilage in several food matrices. In this work, we tested the antimicrobial activity of EOs from Melissa officinalis, Ocimum basilicum, and Thymus vulgaris against three different microorganisms: Escherichia coli, Clostridium tyrobutyricum, and Penicillium verrucosum. Pressed ewes' cheese made from milk fortified with EOs (250 mg/kg) was used as a model. The carryover effect of each oil was studied by analyzing the volatile fraction of dairy samples along the cheese-making process using headspace stir bar sorptive extraction coupled to gas chromatography/mass spectrometry. Results showed that the EOs contained in T. vulgaris effectively reduced the counts of C. tyrobutyricum and inhibited completely the growth of P. verrucosum without affecting the natural flora present in the cheese. By contrast, the inhibitory effect of M. officinalis against lactic acid bacteria starter cultures rendered this oil unsuitable for this matrix. [ABSTRACT FROM AUTHOR]

Abstract: An analytical method was developed for simultaneous determination of 50 volatiles in pressed ewe cheese using headspace sorptive extraction coupled to a thermal desorption and gas chromatography mass spectrometry. Method optimization was carried out in terms of chromatographic columns and conditions, stir bar size and holder, vial volume, salt content, sample weight, extraction temperature and time. The proposed method was validated showing good results in linearity (>0.98), precision (9–34%), recovery (58–120%), limit of detection (6–38 ng kg−1) and limit of quantitation (75–150 ng kg−1). The present method was also applied for the analysis of volatiles in ewes’ milk cheese samples. [Copyright &y& Elsevier]