Active Whey Protein Edible Films and Coatings Incorporating Lactobacillus buchneri for Penicillium nordicum Control in Cheese

Sheep's Second Cheese Whey Edible Coatings with Oregano and Clary Sage Essential Oils Used as Sustainable Packaging Material in Cheese

Sheep's second cheese whey (SCW), the by-product resulting from whey cheese production, was used as a component of cheese coatings containing oregano (Origanum compactum) and clary sage (Salvia sclarea) essential oils (EOs). SCW powder was obtained by the ultrafiltration/diafiltration of SCW followed by reverse osmosis and freeze drying. The coatings were produced with a mixture of SCW and whey protein isolate (WPI) using glycerol as plasticizer. Model cheeses were produced with cow´s milk and those containing SCW:WPI coatings; those with and without EOs were compared to controls without coating and with a commercial coating containing natamycin. At the end of ripening (28 days), the cheeses containing EOs presented higher water activity (ca. 0.930) and moisture content, as well as lower titratable acidity. Concerning color parameters, significant differences were also observed between products and as a result of ripening time. However, the use of SCW:WPI coatings did not significantly influence the color parameters at the end of ripening. Regarding texture parameters, the cheeses containing SCW:WPI coatings presented significantly lower values for hardness, chewiness, and gumminess. Significant differences were also observed for all microbial groups evaluated either between products and as a result of ripening time. In all cases, lactobacilli and lactococci counts surpassed log 7-8 CFU/g, while the counts of yeasts and molds increased steadily from ca. log 3 to log 6 CFU/g. The lowest counts of yeasts and molds were observed in the samples containing natamycin, but nonsignificant differences between products were observed. In conclusion, SCW:WPI cheese coatings can successfully substitute commercial coatings with the advantage of being edible packaging materials manufactured with by-products.

Biocontrol of Pathogen Microorganisms in Ripened Foods of Animal Origin

Ripened foods of animal origin comprise meat products and dairy products, being transformed by the wild microbiota which populates the raw materials, generating highly appreciated products over the world. Together with this beneficial microbiota, both pathogenic and toxigenic microorganisms such as Listeria monocytogenes, Salmonella enterica, Staphylococcus aureus, Clostridium botulinum, Escherichia coli, Candida spp., Penicillium spp. and Aspergillus spp., can contaminate these products and pose a risk for the consumers. Thus, effective strategies to hamper these hazards are required. Additionally, consumer demand for clean label products is increasing. Therefore, the manufacturing sector is seeking new efficient, natural, low-environmental impact and easy to apply strategies to counteract these microorganisms. This review gathers different approaches to maximize food safety and discusses the possibility of their being applied or the necessity of new evidence, mainly for validation in the manufacturing product and its sensory impact, before being implemented as preventative measures in the Hazard Analysis and Critical Control Point programs.

Prevention of Fungal Contamination in Semi-Hard Cheeses by Whey–Gelatin Film Incorporated with Levilactobacillus brevis SJC120

Cheese whey fermented by lactic acid bacteria (LAB) was used to develop an edible film with antifungal properties. Five LAB strains isolated from artisanal cheeses were screened for antifungal activity and incorporated into a whey–gelatin film. Of the strains tested, Levilactobacillus brevis SJC120 showed the strongest activity against five filamentous fungi isolated from cheese and cheese-making environment, at both 10 °C and 20 °C. The cell-free supernatant from L. brevis inhibited fungal growth by more than 80%. Incorporation of bacterial cells into the film did not alter the moisture content, water vapor permeability, or mechanical and optical properties. The whey–gelatin film was also able to maintain the viability of L. brevis cells at 107 log CFU/g after 30 days at 10 °C. In cheeses wrapped with L. brevis film, the size of fungal colonies decreased by 55% to 76%. Furthermore, no significant differences (p > 0.05) were observed in cheese proteolysis or in the moisture, fat, and protein content of the cheese wrapped with films. The results showed that whey–gelatin film with L. brevis SJC120 can reduce the contamination of cheese with filamentous fungi and could be used as an alternative to conventional cheese preservation and packaging.

Edible alginate-based films with anti-SARS-CoV-2 activity

The viability of SARS-CoV-2 on food surfaces and its propagation through the food chain has been discussed by several stakeholders, as it may represent a serious public health problem, bringing new challenges to the food system. This work shows for the first time that edible films can be used against SARS-CoV-2. Sodium alginate-based films containing gallic acid, geraniol, and green tea extract were evaluated in terms of their antiviral activity against SARS-CoV-2. The results showed that all these films have strong in vitro antiviral activity against this virus. However, a higher concentration of the active compound (1.25%) is needed for the film containing gallic acid to achieve similar results to those obtained for lower concentrations of geraniol and green tea extract (0.313%). Furthermore, critical concentrations of the active compounds in the films were used to evaluate their stability during storage. Results showed that gallic acid-loaded films lose their activity from the second week of storage, while films with geraniol and green tea extract only show a drop in activity after four weeks. These results highlight the possibility of using edible films and coatings as antiviral materials on food surfaces or food contact materials, which may help to reduce the spreading of viruses through the food chain.

Application of Edible Coating Based on Liquid Acid Whey Protein Concentrate with Indigenous Lactobacillus helveticus for Acid-Curd Cheese Quality Improvement

Edible coatings as carriers for protective lactic acid bacteria (LAB) can enhance hygienic quality to dairy products. Thus, the aim of this study was to improve the quality of artisanal acid-curd cheese by applying liquid acid whey protein concentrate based edible coating with entrapped indigenous antimicrobial Lactobacillus helveticus MI-LH13. The edible fresh acid-curd cheese coating was composed of 100% (w/w) liquid acid whey protein concentrate (LAWPC), apple pectin, sunflower oil, and glycerol containing 6 log10 CFU/mL of strain biomass applied on cheese by dipping. The cheese samples were examined over 21 days of storage for changes of microbiological criteria (LAB, yeast and mould, coliform, enterobacteria, and lipolytic microorganism), physicochemical (pH, lactic acid, protein, fat, moisture content, and colour), rheological, and sensory properties. The coating significantly improved appearance and slowed down discolouration of cheese by preserving moisture during prolonged storage. The immobilisation of L. helveticus cells into the coating had no negative effect on their viability throughout 14 days of storage at 4 °C and 23 °C. The application of coating with immobilised cells on cheeses significantly decreased the counts of yeast up to 1 log10 CFU/g during 14 days (p < 0.05) of storage and suppressed growth of mould for 21 days resulting in improved flavour of curd cheese at the end of storage. These findings indicate that LAWPC-pectin formulation provided an excellent matrix to support L. helveticus cell viability. Acting as protective antimicrobial barrier in fresh cheeses, this bioactive coating can reduce microbial contamination after processing enabling the producers to extend the shelf life of this perishable product.

A Comprehensive Study on Gelatin- and Whey Protein Isolate-Based Edible Films as Carriers of Fireweed (Epilobium angustifolium L.) Extract

Gelatin (GEL) and whey protein isolate (WPI) are often taken into account as carriers of phytoantioxidants for developing active packaging. The materials obtained, however, have not yet been systematically compared to demonstrate their potential benefits and drawbacks. Fireweed extract (FE) is a rich source of polyphenols with high antioxidant activity. Therefore, in this study, the structural, physicochemical, and antiradical properties of GEL and WPI films incorporated with freeze-dried fireweed extract (FE; 0, 0.0125, 0.025, 0.05%) were simultaneously evaluated. As verified by X-ray diffraction, the GEL-based films were more crystalline and, consequently, mechanically stronger (~ 9–11 vs. ~ 6 MPa) and less permeable to water vapor than the WPI films (44.95–52.02 vs. 61.47–70.49 g mm m−2 day−1 kPa−1). Furthermore, GEL offered a bit more transparent, less yellow, and more stretchable films (~ 50–59% vs. ~ 26%). In turn, the WPI films had superior UV-protective potential. The higher FE concentration yielded more yellow films with improved UV-blocking ability. The FE (0.05%) made the GEL cryogel denser. Based on the half-time reduction of 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (tABTS50%), the 0.025, and 0.05% FE-supplemented WPI films exhibited ~ 1.6 and ~ 1.9 times better antiradical potential than the GEL counterparts. This result implies that the WPI-based films, being more soluble (35.12–36.74 vs. 31.51–33.21%) and less swellable (192.61–205.88 vs. 1056.93–2282.47%), ensured faster release of FE into aqueous medium. The slower building up of the antiradical activity of the FE-supplemented GEL films suggests that GEL could be more useful in the development of slow/less migratory active packaging systems for high moisture food.

Eco-friendly 'ochratoxin A' control in stored licorice roots - quality assurance perspective

According to toxicity data, ochratoxin A (OTA) is the second most important mycotoxin and is produced by Aspergillus and Penicillium. As a natural antifungal agent, clove essential oil (CEO) is a substance generally recognised as safe (GRAS) and shows strong activity against fungal pathogens. Here, we aimed to investigate the control efficacy of CEO in nano-emulsions (CEN) against OTA production in licorice roots and rhizomes during storage. The experiments were performed under simulated conditions of all four seasons (i.e. Spring, Summer, Autumn and Winter). Relative humidity (RH) and temperature were simulated in desiccators along with various salt solutions in incubators. Fresh licorice roots were immersed in CEN at various concentrations (150, 300, 600, 1200 and 2400 µl/l). Before utilising the nano-emulsions, we measured their polydispersity index and mean droplet size by the dynamic light scattering (DLS) technique. Also, the chemical composition of the CEO was determined using GC and GC-MS analyses. Sampling was carried out to monitor OTA once every five days. The samples were dried immediately and analysed by high-performance liquid chromatography (HPLC). Results showed that various concentrations of CEN inhibited the growth of fungi and OTA production. The most effective CEN concentrations were 1200 and 2400 µl/l, which reduced OTA production to 19 and 20 ppb under Winter and Autumn conditions, respectively. These results suggest an effective eco-friendly method for the storage of licorice to reduce postharvest fungal decay.

Application of innovative packaging technologies to manage fungi and mycotoxin contamination in agricultural products: Current status, challenges, and perspectives

The consumer demand for safe, "healthy," and premium foods, preferably with an extended shelf-life; demand for easy packaging; and choice for more sustainable food packaging have contributed to the development of novel packaging technologies. The application of adequate packaging materials has recently become a major post-harvest challenge concerning the control of fungi and mycotoxin. This review will describe the current antifungal packaging technology involved to prevent the contamination of fungi and mycotoxin, along with the characteristics and mechanism of action in food products. Antifungal packaging has incredible potential in the food packaging sector. The most suitable approach for the safe storage of agricultural produce for farmers is the hermetic packaging technology, which maintains quality while providing a good barrier against fungi and mycotoxin. Furthermore, active antifungal packaging is a viable method for incorporating antifungal agents against pathogenic fungi. Essential oils and organic acid have received more scientific attention due to their increased efficacy against mold growth. Polypeptides, chitosan, and natamycin incorporated in active packaging significantly reduced fungi. Even though nanotechnological advancements in antifungal packaging are promising, safety and regulation issues remain significant concerns.

The control of fungi and mycotoxins by food active packaging: a review

Conventionally used petrochemical-based plastics are poorly degradable and cause severe environmental pollution. Alternatively, biopolymers (e.g., polysaccharides, proteins, lipids, and their blends) are biodegradable and environment-friendly, and thus their use in packaging technologies has been on the rise. Spoilage of food by mycotoxigenic fungi poses a severe threat to human and animal health. Hence, because of the adverse effects of synthetic preservatives, active packaging as an effective technique for controlling and decontaminating fungi and related mycotoxins has attracted considerable interest. The current review aims to provide an overview of the prevention of fungi and mycotoxins through active packaging. The impact of different additives on the antifungal and anti-mycotoxigenic functionality of packaging incorporating active films/coatings is also investigated. In addition, active packaging applications to control and decontaminate common fungi and mycotoxins in bakery products, cereal grains, fruits, nuts, and dairy products are also introduced. The results of recent studies have confirmed that biopolymer films and coatings incorporating antimicrobial agents provide great potential for controlling common fungi and mycotoxins and enhancing food quality and safety.

Edible films and coatings: properties for the selection of the components, evolution through composites and nanomaterials, and safety issues

Edible films and coatings, despite their practical applications, have only entered the food industry in the last decade. Their main functions are to protect the food products from mechanical damage and from physical, chemical and microbiological deteriorative changes. The ingredients used for their formation are polysaccharides, proteins and lipids, in individual or combined formulations. The edible films and coatings have already been applied on various food products, such as fruits, vegetables, meat products, seafood products, cheese, baked products and deep fat fried products. The techniques for their application on foods are of particular interest. Nowadays, composite edible films and coatings are also being studied, based on combinations of the properties of individual components. In addition to conventional materials, new ones, such as nanomaterials, are being investigated, aiming to enhance the resulting properties. However, before the incorporation of new materials to films and coatings, they must be thoroughly checked according to the legislation, to assure their lawful use. This review covers the recent developments on the edible films and coatings area in terms of the contribution of novel constituting materials to the improvement of their properties.