Antimicrobial Edible Films Research Articles

Prediction of the coating requirements for smoked salmon protection against Listeria monocytogenes using a defatted mustard meal-based antimicrobial edible film containing thiocyanates

The antimicrobial film-coating requirements for obtaining protection against Listeria monocytogenes in smoked salmon using a defatted mustard meal-based antimicrobial edible film (DMM film) were predicted by fitting a mathematical model to the experimental data. The concentration of thiocyanate ion (SCN−) (0.28 ± 0.02 mg/g) inhibiting L. monocytogenes (4.0 ± 0.2 log CFU/g) as well as diffusion and partition coefficients of SCN− in smoked salmon coated with the film were experimentally determined for prediction. The diffusion coefficients for the SCN− diffusion in the film and in the salmon at 4 °C and the partition coefficient were 2.7 × 10−14 m2/s, 1.9 × 10−10 m2/s, and 0.8, respectively. The film containing an SCN− at 0.41 mg/g was predicted to provide 19.7 h of protection in smoked salmon against continuous-post-contamination by L. monocytogenes at 4.0 log CFU/g during which SCN− remains above the inhibitory concentration of 0.28 mg/g. For 24 h inhibition, the necessary initial concentration of SCN− was estimated as 0.43 mg/g in a 0.14 mm thick film. The methods developed in this study allow for the prediction of antimicrobial DMM film requirements in the protection of smoked salmon against L. monocytogenes.

Chemistry and multibeneficial bioactivities of carvacrol (4-isopropyl-2-methylphenol), a component of essential oils produced by aromatic plants and spices.

Aromatic plants produce organic compounds that may be involved in the defense of plants against phytopathogenic insects, bacteria, fungi, and viruses. One of these compounds, called carvacrol, which is found in high concentrations in essential oils such as oregano, has been reported to exhibit numerous bioactivities in cells and animals. This integrated overview surveys and interprets our present knowledge of the chemistry and analysis of carvacrol and its beneficial bioactivities. These activities include its antioxidative properties in food (e.g., lard, sunflower oil) and in vivo and the inhibition of foodborne and human antibiotic-susceptible and antibiotic-resistant pathogenic bacteria, viruses, pathogenic fungi and parasites, and insects in vitro and in human foods (e.g., apple juice, eggs, leafy greens, meat and poultry products, milk, oysters) and food animal feeds and wastes. Also covered are inhibitions of microbial and fungal toxin production and the anti-inflammatory, analgesic, antiarthritic, antiallergic, anticarcinogenic, antidiabetic, cardioprotective, gastroprotective, hepatoprotective, and neuroprotective properties of carvacrol as well as metabolic, synergistic, and mechanistic aspects. Areas for future research are also suggested. The collated information and suggested research might contribute to a better understanding of agronomical, biosynthetic, chemical, physiological, and cellular mechanisms of the described health-promoting effects of carvacrol, and facilitate and guide further studies needed to optimize the use of carvacrol as a multifunctional food in pure and encapsulated forms, in edible antimicrobial films, and in combination with plant-derived and medical antibiotics to help prevent or treat animal and human diseases.

Antimicrobial and physical-mechanical properties of pectin/papaya puree/cinnamaldehyde nanoemulsion edible composite films

The rising demand for bio-based materials to be used in food packaging has encouraged the development of novel, environmentally-friendly films. Fruit puree has the potential to be incorporated in the film-forming solution so that to produce edible films. The major components of plant essential oils (e.g., cinnamaldehyde) deliver antimicrobial properties against food pathogens and may be released by active films in an effort to replace synthetic preservatives. This work aimed at producing cinnamaldehyde nanoemulsions of different droplet sizes, as well as assessing the effect of papaya puree and cinnamaldehyde droplet diameter in the antimicrobial and physical-mechanical properties of high or low methylester pectin films. Increased stirring energies reduced droplet diameter. Papaya puree reduced films’ resistance and rigidity while increased extensibility and water vapor permeability. Cinnamaldehyde nanoemulsions balanced the plasticizing effect of papaya puree by increasing rigidity and decreasing extensibility and permeability to water vapor of pectin films. Also, cinnamaldehyde provided antimicrobial properties against Escherichia coli, Salmonella enterica, Listeria monocytogenes, and Staphylococcus aureus. The reduction on droplet diameter did not influence the physical-mechanical properties of the films, but remarkably improved bacterial inhibition due to the higher delivery of active compounds having increased surface areas. Antimicrobial edible films from renewable sources were successfully produced here, and the improved bacterial inhibition provided by the same cinnamaldehyde content with smaller nanodroplets may play an important role in reducing preservative content as required by consumers.

Properties of lysozyme/low methoxyl (LM) pectin complexes for antimicrobial edible food packaging

The objective of this study was to determine the properties of lysozyme/low methoxyl (LM) pectin complexes in order to develop an edible antimicrobial film. At a constant lysozyme concentration (0.714g/L), the gradual LM pectin addition (0–2g/L) induced an increase of turbidity up to a threshold LM pectin concentration above which turbidity decreased. These results were interpreted in terms of lysozyme/LM pectin complexes formation followed by a change in the apparent particle size distribution and the electrophoretic mobility (ζ-potential). This complex formation was shown to considerably decrease the lysozyme antimicrobial activity probably due to lysozyme substrate diffusional limitation and/or a decrease of the enzyme mobility. The formed complexes were then used to manufacture an edible antimicrobial film able to control the lysozyme release. The presence of pectinases in the release medium enhanced the lysozyme release confirming that the developed edible antimicrobial film can be used to protect foods against lysozyme sensitive microorganisms and particularly those producing pectinolytic enzymes.

Antimicrobial edible films and coatings for meat and meat products preservation.

Animal origin foods are widely distributed and consumed around the world due to their high nutrients availability but may also provide a suitable environment for growth of pathogenic and spoilage microorganisms. Nowadays consumers demand high quality food with an extended shelf life without chemical additives. Edible films and coatings (EFC) added with natural antimicrobials are a promising preservation technology for raw and processed meats because they provide good barrier against spoilage and pathogenic microorganisms. This review gathers updated research reported over the last ten years related to antimicrobial EFC applied to meat and meat products. In addition, the films gas barrier properties contribute to extended shelf life because physicochemical changes, such as color, texture, and moisture, may be significantly minimized. The effectiveness showed by different types of antimicrobial EFC depends on meat source, polymer used, film barrier properties, target microorganism, antimicrobial substance properties, and storage conditions. The perspective of this technology includes tailoring of coating procedures to meet industry requirements and shelf life increase of meat and meat products to ensure quality and safety without changes in sensory characteristics.

STABILITY OF ANTIMICROBIAL ACTIVITY OF PULLULAN EDIBLE FILMS INCORPORATED WITH NANOPARTICLES AND ESSENTIAL OILS AND THEIR IMPACT ON TURKEY DELI MEAT QUALITY

Edible films containing antimicrobials are gaining importance as potential treatment to extend product shelf life and reduce risk of pathogens. Antimicrobial activities of pullulan films incorporated silver nanoparticles (Ag NPs) 100 nm, zinc oxide nanoparticles (ZnO NPs) 110 nm, oregano oil (OR) 2% and rosemary oil (RO) 2%, against Listeria monocytogenes andStaphylococcus aureus, were evaluated during the preparation and storage at 4, 25, 37, and 55°C up to 49 days in plate overlay assays (in vitro). Moreover, the prior pullulan films were applied directly on turkey deli meat were inoculated by L.monocytogenes andS. aureus and stored at 4 °C for two weeks. The results from this study demonstrate that Ag NPs and OR edible films more active than ZnO NPs and RO, respectively. The optimum conditions for storage pullulan edible films incorporated nanoparticles (NPs) and/or essential oils (EOs) were 4 and 25°C. Ag NPs, ZnO NPs, OR, and RO based films were exhibited significant effects as antibacterial activity against pathogens. These results revealed that (NPs) and/or (EOs) have a good potential to be incorporated into pullulan to make an antimicrobial edible film or coating for various food applications.

Development of antimicrobial defatted soybean meal-based edible films incorporating the lactoperoxidase system by heat pressing

Antimicrobial edible films were developed using defatted soybean meal (DSM), a lactoperoxidase system (LPOS), and heat pressing. DSM-based films were formed at 70–90°C and 40–50MPa for 3min, varying with the concentrations of DSM, xanthan, glycerol, and water in the formulation. The tensile strength, elongation, elastic modulus, and moisture vapor permeability of the DSM films were 1.2–5.4MPa, 0.7–19.5%, 19.6–505.4MPa, and 2.6–6.8gmmkPa−1h−1m−2, respectively. The LPOS-DSM film inhibited Salmonella Typhimurium by 1.5log CFU/disk. The diffusion coefficients for the diffusion of antimicrobial hypothiocyanite (OSCN−) in the LPOS-DSM film coated on ham and a gel foodwere 1.8–10.7×10−15m2s−1. As the water activity of the food or storage temperature increased, the coefficient also increased. These results demonstrated the feasibility of producing edible films from DSM on a large scale, which can potentially be used as a food coating to decontaminate S. Typhimurium on food surfaces by controlled release of antimicrobials.

Whey protein isolate edible films with essential oils incorporated to improve the microbial quality of poultry

Whey protein isolate edible films with oregano or clove essential oils (EOs) incorporated as natural antimicrobials have been developed, with the aim of enhancing the microbial quality of poultry. The effectiveness of the films was determined against both the whole and selected microbiota developed during different periods of cold storage on the surface of skinless chicken breast. Tests were conducted by using both turbidimetric and agar disc diffusion methods. The antimicrobial edible films developed showed high effectiveness against the main spoilers developed on the surface of skinless chicken breasts cold-stored for 8 days. The films based on oregano EO showed greater effectiveness than those based on clove EO. Still, clove EO could be part of an effective antimicrobial edible film. Enterobacteriaceae was the most susceptible to the effect of the films when lower concentrations of EO were incorporated. The largest inhibition surfaces obtained were provoked by films with the highest concentration of oregano EO incorporated against lactic acid bacteria. The antimicrobial edible films developed in this study inhibited the growth of the microbial populations that developed through storage of the chicken breast and caused its spoilage. The results of this research have direct application in the food industry to enhance the control of the development of spoilers such as Pseudomonas spp. or lactic acid bacteria.

Antimicrobial Activity and Hydrophobicity of Edible Whey Protein Isolate Films Formulated with Nisin and/or Glucose Oxidase

The use of edible antimicrobial films has been reported as a means to improve food shelf life through gradual releasing of antimicrobial compounds on the food surface. This work reports the study on the incorporation of 2 antimicrobial agents, nisin (N), and/or glucose oxidase (GO), into the matrix of Whey protein isolate (WPI) films at pH 5.5 and 8.5. The antimicrobial activity of the edible films was evaluated against Listeria innocua (ATCC 33090), Brochothrix thermosphacta (NCIB10018), Escherichia coli (JMP101), and Enterococcus faecalis (MXVK22). In addition, the antimicrobial activity was related to the hydrophobicity and water solubility of the WPI films. The greatest antibacterial activity was observed in WPI films containing only GO. The combined addition of N and GO resulted in films with lower antimicrobial activity than films with N or GO alone. In most cases, a pH effect was observed as greater antimicrobial response at pH 5.5 as well as higher film matrix hydrophobicity. WPI films supplemented with GO can be used in coating systems suitable for food preservation.

Antimicrobial Activity of Whey Protein Isolate Edible Films with Essential Oils against Food Spoilers and Foodborne Pathogens

The use of antimicrobial edible film is proposed as a means of improving food safety and extending the shelf-life of food systems by controlling the release of antimicrobials on food surfaces. In this work we first selected and studied 8 different essential oils (EOs) from plants, namely, oregano, clove, tea tree, coriander, mastic thyme, laurel, rosemary, and sage as natural antimicrobials against 2 gram-positive bacteria (Listeria innocua and Staphylococcus aureus) and 2 gram-negative bacteria (Salmonella enteritidis and Pseudomona fragi) by using the agar disk diffusion method. EOs from oregano, clove, and tea tree produced the largest surfaces of inhibition against the growth of the 4 bacterial strains tested. Second and following the assessment of compatibility, stable antimicrobial edible films based on whey protein isolate (WPI) with increasing concentrations (0.5% to 9%) of the 8 EOs were developed and tested for antimicrobial activity against the same gram-positive and gram-negative bacteria. WPI-edible films incorporating oregano or clove EO were found to have the most intense inhibitory effect of microbial growth. The bacterial strain gram-negative P. fragi presented the less susceptibility to the effect of those films. Moreover, only the edible films based on these 2 EOs were active against all 4 studied microorganisms. On the other hand, the edible films incorporating tea tree, coriander, mastic thyme, laurel, rosemary, or sage EOs even at high concentrations (7% to 9%) did not cause any antimicrobial effect against the pathogens S. aureus or S. enteritidis. Potential applications of this technology can introduce direct benefits to the food industry by improving safety and microbial product quality. The results of this research have direct application in the food industry with potential applications in various foodstuffs, including meat and poultry products where the control of spoilage bacteria such as P. fragi throughout their chilled storage or the improvement of food safety by controlling pathogens such as S. enteritidis are topics of particular interest for the industry.

Listeria monocytogenes inhibition by defatted mustard meal-based edible films

An antimicrobial edible film was developed from defatted mustard meal (Sinapis alba) (DMM), a byproduct from the bio-fuel industry, without incorporating external antimicrobials and its antimicrobial activity against Listeria monocytogenes and physical properties were investigated. The DMM colloidal solution consisting of 184 g water, 14 g DMM, and 2g glycerol was homogenized and incubated at 37°C for 0.2, 0.5, 24 or 48 h to prepare a film-forming solution. The pH of a portion of the film-forming solution (pH 5.5) was adjusted to 2.0 or 4.0. Films were formed by drying the film-forming solutions at 23°C for 48 h. The film-forming solution incubated for 48 h inhibited L. monocytogenes in broth and on agar media. Antimicrobial effects of the film prepared from the 48 h-incubated solution increased with decrease in pH of the solution from 5.5 to 2.0. The film from the film forming solution incubated for 48 h (pH 2.0) initially inhibited more than 4.0 log CFU/g of L. monocytogenes inoculated on film-coated salmon. The film-coating retarded the growth of L. monocytogenes in smoked salmon at 5, 10, and 15°C and the antimicrobial effect during storage was more noticeable when the coating was applied before inoculation than when it was applied after inoculation. The tensile strength, percentage elongation, solubility in watercxu, and water vapor permeability of the anti microbial film were 2.44 ± 0.19 MPa, 6.40 ± 1.13%, 3.19 ± 0.90%, and 3.18 ± 0.63 gmm/kPa hm(2), respectively. The antimicrobial DMM films have demonstrated a potential to be applied to foods as wraps or coatings to control the growth of L. monocytogenes.

Antimicrobial Edible Films and Coatings for Fresh and Minimally Processed Fruits and Vegetables: A Review

The use of edible films and coatings is an environmentally friendly technology that offers substantial advantages for shelf-life increase of many food products including fruits and vegetables. The development of new natural edible films and coatings with the addition of antimicrobial compounds to preserve fresh and minimally processed fruits and vegetables is a technological challenge for the industry and a very active research field worldwide. Antimicrobial agents have been successfully added to edible composite films and coatings based on polysaccharides or proteins such as starch, cellulose derivatives, chitosan, alginate, fruit puree, whey protein isolated, soy protein, egg albumen, wheat gluten, or sodium caseinate. This paper reviews the development of edible films and coatings with antimicrobial activity, typically through the incorporation of antimicrobial food additives as ingredients, the effect of these edible films on the control of target microorganisms, the influence of antimicrobial agents on mechanical and barrier properties of stand-alone edible films, and the effect of the application of antimicrobial edible coatings on the quality of fresh and fresh-cut fruits and vegetables.

Investigation on Development of Zein Antimicrobial Edible Film and Essential oil of Zataria multiflora Boiss. on Salmonella enteritidis, Listeria monocytogenes, Escherichia coli and Staphylococcus aureus

Active packaging is a type of packaging that can control or react to things arranged inside the packaging. In this case some types of active packaging will control the temperature inside the packaging while others control the moisture levels. It can also have systems that are antimicrobial, which extend the shelf life of their contents without the need of additives. An antimicrobial active packaging is made by incorporating antimicrobial agents in food packages. The film containing antimicrobial/antioxidant agents are a type of active packaging, which is designed mainly to control microbial and chemical spoilage of food. In this study, antimicrobial/antioxidant zein films are developed by incorporation of Zataria multiflora Boiss. essential oil (ZEO). Zataria multiflora Boiss. is a plant that belongs to the Lamiaceae family and grows only in Iran, Pakistan and Afghanistan. The antimicrobial activities of the plant are also well established against a wide variety of bacteria. Ayana et al. studied the antimicrobial effect of the methylcellulose (MC) films containing (% 0.5-3 w/v) olive leaf extract and glycerol (% 1.6 v/v). The results show the films were effective to decrease the amount of the St. aureus (ATCC 25923). The olive leaf extract in the films caused a reduce in the water vapour permeability and elongation (E), Investigation on Development of Zein Antimicrobial Edible Film and Essential Oil of Zataria multiflora Boiss. on Sallmonella enteritidis, Listeria monocytogenes, Escherichia coli and Staphylococcus aureus†

Physical and Antibacterial Properties of Edible Films Formulated with Apple Skin Polyphenols

Fruit and vegetable skins have polyphenolic compounds, terpenes, and phenols with antimicrobial and antioxidant activity. These flavoring plant essential oil components are generally regarded as safe. Edible films made from fruits or vegetables containing apple skin polyphenols have the potential to be used commercially to protect food against contamination by pathogenic bacteria. The main objective of this study was to evaluate physical properties as well as antimicrobial activities against Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella enterica of apple skin polyphenols at 0% to 10% (w/w) concentrations in apple puree film-forming solutions formulated into edible films. Commercial apple skin polyphenol powder had a water activity of 0.44 and high total soluble phenolic compounds and antioxidant capacity (995.3 mg chlorogenic acid/100 g and 14.4 mg Trolox/g, respectively). Antimicrobial activities of edible film containing apple skin polyphenols were determined by the overlay method. Apple edible film with apple skin polyphenols was highly effective against L. monocytogenes. The minimum concentration need to inactive L. monocytogenes was 1.5%. However, apple skin polyphenols did not show any antimicrobial effect against E. coli O157:H7 and S. enterica even at 10% level. The presence of apple skin polyphenols reduced water vapor permeability of films. Apple skin polyphenols increased elongation of films and darkened the color of films. The results of the present study show that apple skin polyphenols can be used to prepare apple-based antimicrobial edible films with good physical properties for food applications by direct contact.

Evaluation of antimicrobial and physical properties of edible film based on carboxymethyl cellulose containing potassium sorbate on some mycotoxigenic Aspergillus species in fresh pistachios

Active packaging is a relatively novel concept of packaging that changes the conditions of the packaged food to extend its shelf-life and improve its safety. In this study, antimicrobial effects of carboxymethyl cellulose based-edible film containing potassium sorbate as an antimicrobial agent were studied against Aspergillus flavus (PTCC-5004), Aspergillus parasiticus (PTCC-5286) and A. parasiticus (PTCC-5018) by using agar diffusion assay. Results showed suitable inhibition effects against A. parasiticus (PTCC-5286) and A. flavus (PTCC-5004) in comparison with A. parasiticus (PTCC-5018). Pistachios were coated with this edible antimicrobial film containing three concentrations of sorbate (1, 0.5 and 0.25 g/100 mL film solution); all concentrations showed no growth of molds. Tensile strength values of films with potassium sorbate, decreased when compared to control, and film’s flexibility, was 28.82 percent for 3 g/100 mL sorbate, while higher concentration of sorbate, decreased the flexibility. The water vapor permeability values (WVP) of films were determined to be 1.18 (g mm/m 2 day kPa) for films plasticized with glycerol, without sorbate while WVP values for the films containing 1 and 2 g/100 mL sorbate increased to 3.77 and 15.5 (g mm/m 2 day kPa), respectively. The observed glass transition temperature ( T G ) depression for these polymer blends was related to the plasticizer content (water, polyethylene, and glycerol), especially water.

PREPARATION AND PROPERTIES OF ANTIBACTERIAL ALGINATE FILMS INCORPORATING EXTRUDED WHITE GINSENG EXTRACT

ABSTRACT Preparation of antibacterial alginate films incorporating extruded white ginseng (EWG) extracts was attempted. The antibacterial effect of EWG extract on six selected food pathogenic bacteria was compared with the effect of red ginseng (RG) and white ginseng (WG) extracts. The EWG was processed in a twin-screw extruder with feed moisture of 20% and barrel temperature of 115 and 130C. The data obtained by agar diffusion assay demonstrated that the film containing 1 g/mL of EWG at barrel temperatures of 115 (EWG-115) and 130C (EWG-130) exhibited stronger antibacterial activity against the four strains of bacteria than the other extracts RG and WG. All films sampled showed reduction in bacteria cell counts (log cycle) compared with the control. After 24 h of incubation, Pseudomonas aeruginosa, Bacillus subtilis and Listeria monocytogenes showed the lowest count in films incorporating EWG-115; the cell reductions were 9.1, 7.46 and 8.31 log cfu/mL, respectively. PRACTICAL APPLICATIONS Extrusion technology has the practical benefit of achieving a uniform product quality and higher productivity. Developing a ginseng antibacterial film will benefit the Korean food system by ensuring healthy foods. Films containing extruded ginseng extracts were more effective against bacteria than those containing red or white ginseng. Overall, this study provides the knowledge needed to interpret ginseng-based antimicrobial edible or food packaging films.

Antibacterial Effects of Allspice, Garlic, and Oregano Essential Oils in Tomato Films Determined by Overlay and Vapor‐Phase Methods

Physical properties as well as antimicrobial activities against Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes of allspice, garlic, and oregano essential oils (EOs) in tomato puree film-forming solutions (TPFFS) formulated into edible films at 0.5% to 3% (w/w) concentrations were investigated in this study. Antimicrobial activities were determined by 2 independent methods: overlay of the film on top of the bacteria and vapor-phase diffusion of the antimicrobial from the film to the bacteria. The results indicate that the antimicrobial activities against the 3 pathogens were in the following order: oregano oil > allspice oil > garlic oil. Listeria monocytogenes was less resistant to EO vapors, while E. coli O157:H7 was more resistant to EOs as determined by both overlay and vapor-phase diffusion tests. The presence of plant EO antimicrobials reduced the viscosity of TPFFS at the higher shear rates, but did not affect water vapor permeability of films. EOs increased elongation and darkened the color of films. The results of the present study show that the 3 plant-derived EOs can be used to prepare tomato-based antimicrobial edible films with good physical properties for food applications by both direct contact and indirectly by vapors emanating from the films.

A Preliminary Study on Antimicrobial Edible Films from Pectin and Other Food Hydrocolloids by Extrusion Method

ABSTRACT Antimicrobial edible films were prepared from natural fiber of pectin and other food hydrocolloids for food packaging or wrapping by extrusion followed by compression or blown film method. Microscopic analysis revealed a well-mixed integrated structure of extruded pellets and an even distribution of the synthetic hydrocolloid in the biopolymers. The resultant composite films possess mechanical properties that are comparable to films cast from most natural hydrocolloids that are consumed as foods or components in processed foods. The inclusion of poly(ethylene oxide) alters the textures of the resultant composite films and therefore demonstrates a new technique for the modification of film properties. The composite films were produced in mild processing conditions, thus the films are able to protect the bioactivity of the incorporated nisin, as shown by the inhibition of Listeria monocytogenes bacterial growth by a liquid incubation method.

Antibacterial Activity against E. coli O157:H7, Physical Properties, and Storage Stability of Novel Carvacrol‐Containing Edible Tomato Films

Edible films containing plant antimicrobials are gaining importance as potential treatment to extend product shelf life and reduce risk of pathogen growth on contaminated food surfaces. The main objective of the present study was to evaluate the antimicrobial activities, storage stabilities, and physical-chemical-mechanica1 properties of novel edible films made from tomatoes containing carvacrol, the main constituent of oregano oil. The antimicrobial activities against E. coli O157:H7 and the stability of carvacrol were evaluated during the preparation and storage of tomato-based films made by 2 different casting methods, continuous casting and batch casting. Antimicrobial assays of tomato films indicated that optimum antimicrobial effects occurred with carvacrol levels of approximately 0.75% added to tomato purees before film preparation. HPLC analysis of the films indicated that the carvacrol concentrations and bactericidal effect of the films remained unchanged over the storage period of up to 98 d at 5 and 25 degrees C. Carvacrol addition to the tomato puree used to prepare the films increased water vapor permeability of tomato films. The continuous method for casting of the films appears more suitable for large-scale use than the batch method. This 1st report on tomato-based edible antimicrobial tomato films suggests that these films have the potential to prevent adverse effects of contaminated food and promote human health associated with the consumption of tomatoes.

Effects of plant essential oils and oil compounds on mechanical, barrier and antimicrobial properties of alginate–apple puree edible films

Mechanical, barrier and antimicrobial properties of 0.1–0.5% suspensions of the following essential oils (EOs)/oil compounds (OCs) were evaluated against the foodborne pathogen Escherichia coli O157:H7 in alginate–apple puree edible film (AAPEF): oregano oil/carvacrol; cinnamon oil/cinnamaldehyde; and lemongrass oil/citral. The presence of plant essential oils did not significantly affect water vapor and oxygen permeabilities of the films, but did significantly modify tensile properties. Antimicrobial activities of solutions used to prepare edible films (AAPFFS) were also determined. The results obtained demonstrate that carvacrol exhibited the strongest antimicrobial activity against E. coli O157:H7. The data show that the antimicrobial activities were in the following order: carvacrol > oregano oil > citral > lemongrass oil > cinnamaldehyde > cinnamon oil. This study showed that plant-derived essential oils and their constituents could be used to prepare apple-based antimicrobial edible films for food applications.