Dairy matrix effect on the transference of rosemary (Rosmarinus officinalis) essential oil compounds during cheese making

Antibacterial and antibiofilm effect of essential oils on staphylococci isolated from cheese - application of the oil mixture in a cheese model

The aim of the research was to examine the antimicrobial and antibiofilm effects of angelica, immortelle, laurel, hyssop, and sage plant dust essential oils (EOs) against isolated strains of Staphylococcus spp. from cheeses, in vitro and in the model of white cheese. MALDI-TOF MS analysis confirmed two Staphylococcus aureus strains and two coagulase-negative, identified as S. saprophyticus and S. warneri. All isolates produce biofilm, where the strains of S. aureus showed slightly better adherence. The main component of angelica EO was β-phellandrene (48.19 %), while α-pinene (20.33 %) were dominant in immortelle EO, in hyssop EO cis-pinocamphone (37.25 %), in laurel EO 1,8-cineole (43.15 %) and in sage EO epirosmanol (26.25 %). The sage EO exhibited the strongest antistaphylococcal activity against all isolates. Synergism was also detected in combination of sage with hyssop or laurel EO. Better antibiofilm activity was confirmed for sage EO compared to hyssop EO. The mixture of sage/laurel EOs reduced the total number of staphylococci in the cheese after 4 days. Results indicate that in vitro applied EOs showed significant antistaphylococcal and antibiofilm activity, while the oil mixture reduced the initial total number of staphylococci.

Rosemary: Unrevealing an old aromatic crop as a new source of promising functional food additive-A review

Rosemary (Rosmarinus officinalis L.) is one of the most famous spice plants belonging to the Lamiaceae family as a remarkably beautiful horticultural plant and economically agricultural crop. The essential oil of rosemary has been enthusiastically welcome in the whole world for hundreds of years. Now, it is wildly prevailing as a promising functional food additive for human health. More importantly, due to its significant aroma, food, and nutritional value, rosemary also plays an essential role in the food/feed additive and food packaging industries. Modern industrial development and fundamental scientific research have extensively revealed its unique phytochemical constituents with biologically meaningful activities, which closely related to diverse human health functions. In this review, we provide a comprehensively systematic perspective on rosemary by summarizing the structures of various pharmacological and nutritional components, biologically functional activities and their molecular regulatory networks required in food developments, and the recent advances in their applications in the food industry. Finally, the temporary limitations and future research trends regarding the development of rosemary components are also discussed and prospected. Hence, the review covering the fundamental research advances and developing prospects of rosemary is a desirable demand to facilitate their better understanding, and it will also serve as a reference to provide many insights for the future promotion of the research and development of functional foods related to rosemary.

Mild Heat Treatment and Biopreservatives for Artisanal Raw Milk Cheeses: Reducing Microbial Spoilage and Extending Shelf-Life through Thermisation, Plant Extracts and Lactic Acid Bacteria

The microbial quality of raw milk artisanal cheeses is not always guaranteed due to the possible presence of pathogens in raw milk that can survive during manufacture and maturation. In this work, an overview of the existing information concerning lactic acid bacteria and plant extracts as antimicrobial agents is provided, as well as thermisation as a strategy to avoid pasteurisation and its negative impact on the sensory characteristics of artisanal cheeses. The mechanisms of antimicrobial action, advantages, limitations and, when applicable, relevant commercial applications are discussed. Plant extracts and lactic acid bacteria appear to be effective approaches to reduce microbial contamination in artisanal raw milk cheeses as a result of their constituents (for example, phenolic compounds in plant extracts), production of antimicrobial substances (such as organic acids and bacteriocins, in the case of lactic acid bacteria), or other mechanisms and their combinations. Thermisation was also confirmed as an effective heat inactivation strategy, causing the impairment of cellular structures and functions. This review also provides insight into the potential constraints of each of the approaches, hence pointing towards the direction of future research.

Plant extracts and essential oils in the dairy industry: A review

Plants have been used as food additives worldwide to enhance the sensory qualities of foods and extend their shelf life by reducing or eliminating foodborne pathogens. They also serve as therapeutic agents due to their beneficial effects on human health through their anti-cancerous, anti-inflammatory, antioxidant, and immune-modulatory properties. Plants can be added to food as a dry powder, grated material, paste, juice, or as an extract that can be produced by a variety of methods. Plant extracts and essential oils are concentrated sources of bioactive phytochemicals that can be added to food in small amounts in a variety of forms. These forms include liquid, semi-solid, or dry powder for easy and uniform diffusion. Encapsulation can protect bioactive compounds from temperature, moisture, oxidation, and light, as well as allow for controlling the release of the encapsulated ingredients. Nanoemulsions can enhance the bioactivity of active components. This review explains how plant extracts and essential oils are used in the dairy industry as antimicrobial materials, analyzing their impact on starter bacteria; as natural antioxidants to prevent the development of off-flavors and increase shelf life; and as technological auxiliaries, like milk-clotting enzymes, stabilizers, and flavoring agents. Therefore, plant extracts and essential oils are a better choice for the dairy industry than plants or their parts due to a wide range of applications, homogeneous dispersion, and ability to control the concentration of the bioactive ingredients and enhance their efficiency.

Rosmarinus officinalis L. Essential Oils Impact on the Microbiological and Oxidative Stability of Sarshir (Kaymak)

This study investigated the effect of Rosmarinus officinalis L. essential oil, REO (one, two and three percent) on the microbiological and oxidative stability of Sarshir during 20 days of refrigerated storage (4 °C). Initially, the chemical composition (gas chromatography/mass spectrometry, GC/MS), antimicrobial (paper disc diffusion) and antioxidant (DPPH) properties of REO were evaluated. Then, the microbial safety, oxidative stability (peroxide and anisidine values) and overall acceptability of the product after addition of REO to Sarshir and the subsequent storage period were determined. According to GC/MS analysis, the major components of REO were α-pinene (24.6%), 1,8-cineole (14.1%), camphor (13.5%), camphene (8.1%) and limonene (6.1%), respectively. Moreover, it was also found that Limosilactobacillus fermentum (inhibition zone (IZ) of 23.5 mm) and Salmonella Typhi (IZ of 16.4 mm) were the most sensitive and resistant spoilage and pathogenic bacteria against REO, respectively. In addition, the half-maximal inhibitory concentration (IC50) of the REO was measured at 24.8 mg/mL, while the IC50 value of butylated hydroxytoluene (BHT) was 16.6 mg/mL. The highest and lowest bacterial populations were detected in the control and the sample containing 3% REO, respectively. The control had the highest extent of lipid oxidation, while the lowest peroxide and anisidine values were measured in Sarshir containing 3% REO.

Antimicrobial mechanisms of spice essential oils and application in food industry

Spice essential oils (SEOs) are commonly used in food flavoring and are considered an effective food preservative. It has a broad range of applications and promising development prospects. As a natural food additive, SEOs' antimicrobial effects have been widely studied and utilized towards food preservation. Many SEOs have exhibited significant antimicrobial activities against food-borne pathogenic and food spoilage microorganisms. We reviewed the antibacterial and antifungal properties of SEOs, the active components, their corresponding mechanisms of actions, as well as their application in the food industry, providing a theoretical basis for SEOs' further development and application as natural preservatives.

Understanding the Relationship between Microstructure and Physicochemical Properties of Ultrafiltered Feta-Type Cheese Containing Saturea bachtiarica Leaf Extract

Microwave-assisted extraction was optimized to prepare Satureja bachtiarica leaf (SBL) extract based on antimicrobial (IZD) and antioxidant activities (DPPH) and extraction yield (EY). At optimum condition, i.e., 800 W power and 8 min, the best extraction results with EY = 16%, IZD = 73.56 mm, and DPPH = 24.2% were obtained. To develop a novel Feta-cheese, the influence of SBL extract, rennet, and starter concentrations were evaluated in terms of rheological, textural, and sensorial properties. At the optimized condition, the acceptance, taste, the strength of the network (A), and the distance between sequential cross-linking points (ξ) were 8.13, 8.07, 34,036.12 Pa·s1/z, and 5.41 nm, respectively. At the 60th day of storage time, the lowest z value (the network extensity parameter) of the cheese samples was observed. SEM image texture indices showed a good correlation with the studied instrumental texture parameters during 60 days of storage. The mold and yeast counts and their growth rate in the SBL extract-added cheese were lower than those for control one; whereas, the former cheese showed a greater LAB population between the 80th and 120th days. The antimicrobial and antioxidant qualities of SBL extract showed a significant influence on cheese properties.

Optimizing the Method of Rosemary Essential Oils Extraction by Using Response Surface Methodology (RSM)-Characterization and Toxicological Assessment

Rosemary (Rosmarinus officinalis L.) is a plant with needle-shaped leaves. It is mainly found in Mediterranean regions (Algeria, Morocco and Tunisia). Rosemary essential oil (EO) has several therapeutic virtues that were widely studied. However, the use of this EO is restricted due to its sensitivity to oxidation. Nanoencapsulation based on EO and polymers has been developed as one of the promising techniques to overcome this limitation. In this study, the emphasis was on optimizing the extraction and formulation of a food additive based on rosemary EO. In fact, the results showed that rosemary EO extraction depended on the parameters of the extraction process, and the optimum heating temperature and extraction time were determined using an experimental design methodology. The parameters for extraction were chosen as follows: heating temperature of 250 °C and a hydrodistillation time of 180 min. This optimization revealed that the maximum oil yield can be obtained. Rosemary EO was characterized by a dominance of 1,8-cineole, camphor, α-pinene, borneol and camphene as well as by high antioxidant and antibacterial capacities with low acute toxicity. The obtained formulation of a stable rosemary EO powder can be used as a food additive in several industrial applications.

Pomegranate Byproduct Extracts as Ingredients for Producing Experimental Cheese with Enhanced Microbiological, Functional, and Physical Characteristics

Pomegranate peel and mesocarp, considered as wastes of fruit processing, are rich sources of beneficial phytochemicals, including hydrolyzable tannins and flavonoids, with proven antimicrobial and antioxidant activity, which can be employed for improving the overall quality of food products. In the present study, extracts from pomegranate peel (PPW) and mesocarp (PMW) were obtained through a water extraction method and evaluated for in vitro antimicrobial activity and polyphenol content. The two extracts were then added during the cheese-making process in order to create a new functional cheese with improved microbiological and physico-chemical characteristics. Antimicrobial in vitro assays evidenced a substantial efficacy of both extracts against Staphylococcus aureus, which often causes staphylococcal food poisoning outbreaks linked to the consumption of raw milk cheeses and artisanal cheeses. For this reason, a simulated cheese contamination was carried out in order to assess if pomegranate extracts can exert antimicrobial activity towards this pathogen even when incorporated into the cheese matrix. Milk enriched with pomegranate extracts (PPW and PMW) was used to produce two different experimental cheeses, which were then evaluated for yield, polyphenol content, and microbiological as well as physico-chemical traits throughout the refrigerated storage. Despite the low concentration of the extracts, the treated cheeses showed an increase in firmness and a slight decrease in S. aureus counts, of more than one log unit in comparison to the control cheese, for up to 12 d of cold storage. Such results support the reuse of agro-food byproducts, in substitution to chemical food preservatives, as the key to a circular economy.

Biodiversity and dairy traits of lactic acid bacteria from foliage of aromatic plants before and after dehydration process monitored by a smart sensors system

The main hypothesis of this work was to evaluate the presence of lactic acid bacteria (LAB) intrinsically resistant to plant essential oils in sage (Salvia officinalis L.) and laurel (Laurus nobilis), for future applications in functional cheese production by addition of aromatic herbs. The effect of the drying process on the viability of LAB was evaluated with three biomass densities (3, 4 and 5 kg/m2). The drying densities did not affect weight loss, but influenced the levels of LAB of sage and laurel. A total of 10 different strains of Enterococcus faecium, Enterococcus mundtii, Enterococcus raffinosus and Leuconostoc mesenteroides were identified from laurel, while sage did not host any LAB species. In particular, L. mesenteroides was the only species sensitive to the heat treatment. Only five strains, all enterococci, were resistant to at least one antibiotic, even though no strain showed gelatinase or haemolytic activity. The investigation on the technological traits useful in cheese making demonstrated that all LAB can be considered non starter LAB, because they were characterized by a slow acidification capacity (the pH was still above 6.00 after 3 d) and a very limited autolysis (the maximum decrease of the optical density at 599 nm was barely 0.2).

Antimicrobial Activity of Myrtus communis L. and Rosmarinus officinalis L. Essential Oils against Listeria monocytogenes in Cheese

Listeria monocytogenes has been referred to as a concern microorganism in cheese making due to its ability to survive and grow in a wide range of environmental conditions, such as refrigeration temperatures, low pH and high salt concentration at the end of the production process. Since cheese may be a potential hazard for consumers, especially high-risk consumers (e.g., pregnant, young children, the elderly, people with medical conditions), efforts of the dairy industry have been aimed at investigating new conservation techniques based on natural additives to meet consumers’ demands on less processed foods without compromising the food safety. Thus, the aim of this study was to evaluate the efficacy of Myrtus communis L. (myrtle) and Rosmarinus officinalis L. (rosemary) essential oils (EO) against Listeria monocytogenes ATCC 679 spiked in sheep cheese before ripening. After the cheesemaking process, the samples were stored at 8 °C for 2 h, 1 d, 3 d, 14 d and 28 d. The composition of EO was identified by gas chromatography-mass spectrometry (GC-MS) analysis. Constituents such as 1,8-cineole, limonene, methyl-eugenol, α-pinene, α-terpineol, α-terpinolene and β-pinene were present in both EO, accounting for 44.61% and 39.76% from the total of chemical compounds identified for myrtle and rosemary EO, respectively. According to the chemical classification, both EO were mainly composed of monoterpenes. Minimum inhibitory concentration (MIC) against L. monocytogenes was obtained at 31.25 μL/mL to myrtle EO and at 0.40 μL/mL to rosemary EO. Then, cheeses were inoculated with L. monocytogenes (Ca. 6 log CFU/mL) and EO was added at MIC value. The addition of rosemary and myrtle EO displayed lower counts of L. monocytogenes (p < 0.01) (about 1–2 log CFU/g) during the ripening period compared to control samples. Ripening only influences (p < 0.001) the growth of L. monocytogenes in control samples. Since rosemary and myrtle EO do not exert any negative impact on the growth of native microflora (p > 0.05), their use as natural antimicrobial additives in cheese demonstrated a potential for dairy processors to assure safety against L. monocytogenes.

Essential Oils in Livestock: From Health to Food Quality

Using plant essential oils (EOs) contributes to the growing number of natural plants' applications in livestock. Scientific data supporting the efficacy of EOs as anti-inflammatory, antibacterial and antioxidant molecules accumulates over time; however, the cumulative evidence is not always sufficient. EOs antioxidant properties have been investigated mainly from human perspectives. Still, so far, our review is the first to combine the beneficial supporting properties of EOs in a One Health approach and as an animal product quality enhancer, opening new possibilities for their utilization in the livestock and nutrition sectors. We aim to compile the currently available data on the main anti-inflammatory effects of EOs, whether encapsulated or not, with a focus on mammary gland inflammation. We will also review the EOs' antioxidant activities when given in the diet or as a food preservative to counteract oxidative stress. We emphasize EOs' in vitro and in vivo ruminal microbiota and mechanisms of action to promote animal health and performance. Given the concept of DOHaD (Developmental Origin of Health and Diseases), supplementing animals with EOs in early life opens new perspectives in the nutrition sector. However, effective evaluation of the significant safety components is required before extending their use to livestock and veterinary medicine.

Natural Preservatives from Plant in Cheese Making

Today, consumers are increasingly demanding safety alternatives concerning the use of synthetic additives in the food industry, as well as healthy food. As a result, a major number of plant-derived preservatives have been tested in the food industry. These natural ingredients have antioxidant properties and have shown to increase the bioactive molecules levels and the microbiological stability of the food items. The effect of the plant-based preservatives on the sensorial properties of the new products has also to be considered, because natural preservatives could result in sensorial characteristics that may not be accepted by the consumers. Cheese is a dairy product widely appreciated all over the world, but it is also susceptible to contamination by pathogenic and spoilage microorganisms; therefore, the use of preservatives in cheese making represents an important step. This review deals with one of the innovation in the cheese sector, which is the addition of natural preservatives. Several aspects are discussed, such as the effect of natural ingredients on the microbial stability of cheese, and their influence on the chemical, nutritional and sensorial characteristics of the cheeses. Although the promising results, further studies are needed to confirm the use of natural preservatives from plants in cheese making.

Volatile Transference and Antimicrobial Activity of Cheeses Made with Ewes' Milk Fortified with Essential Oils

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.

Plants: A natural solution to enhance raw milk cheese preservation?

Plants have been traditionnally used for centuries in cheese manufacturing, either for their aromatic properties or as technological auxiliaries (e.g. milk-clotting enzyme preparations, cheese wrappers). Some of these plants are known to have antimicrobial and/or antioxidant properties and could also act as natural preservatives for raw milk and derived dairy products. This review examined the traditional uses of plants in dairy processing, and then focuses on known antimicrobial and antioxidant properties of their extracts (e.g. maceration, decoction, essential oil). Known effects of theses plants on technological flora (starter cultures and microorganisms implicated in cheese ripening) were also summarized, and the potential for plant extracts used in combination with hurdle technologies was explored. Then, legal restriction and bioactivity variations from a culture media to a food matrix was reviewed: non-toxic bioactive molecules found in plants, extract preparation modes suitable with foodgrade processing restrictions, the role of the food matrix as a hindrance to the efficiency of bioactive compounds, and a review of food legislation. Finally, some commercial plant extracts for milk preservation were discussed.