Evaluation of non-thermal hurdle technology for ultraviolet-light to inactivate Escherichia coli K12 on goat meat surfaces

Effect of Ultraviolet-C (UV-C) Irradiation on Foodborne Pathogen Inactivation in Prosciutto and Changes on Its Physicochemical Properties

Ready-to-eat sliced prosciutto samples were treated with ultraviolet (UV) light (wavelength: 265 and 275 nm/intensity: 10 and 50 mW) after inoculation with hepatitis E virus (HEV), Escherichia coli O157:H7, or Listeria monocytogenes. The parameters of prosciutto quality assessed were color, texture, pH, water content, water holding capacity, oxidative rancidity, and freshness. The prosciutto sample under UV-C light was influenced on changes of color, lipid oxidation, and protein oxidation due to free radical generation. UV-C light reduced E. coli O157:H7 and L. monocytogenes counts by up to 2.23 Log and 1.85 Log colony forming units/g, respectively. The amount of HEV was also significantly reduced after treatment (p<0.05). HEV was no longer detected after 10 min of treatment at an intensity of 50 mW. Consequently, UV-C treatment above 265 nm at 50 mW for 10 min is an effective strategy for maintaining product quality and improving food safety. The results of this study advance the application of non-thermal food preservation.

Development and characterization of bilayer chitosan/alginate cling film reinforced with essential oil based nanocomposite for red meat preservation

With a goal to finding suitable alternatives to plastic packaging in the food industry, we developed a multifunctional bio-based active packaging film to enhance the shelf life of red meat. A chitosan/alginate (Chi + Alg) bilayer film was developed through layer-by-layer (LBL) assembly and an active material i.e. lemongrass nanoemulsion with silver nanoparticles-based nanocomposite (NC1) was loaded into the alginate layer to improve the quality of the bio-based film (Chi + Alg + NC1). The Chi + Alg + NC1 film was characterized in terms of its microstructure, mechanical strength, thermal stability, and antimicrobial activity. Scanning electron microscopy (SEM) revealed a film (22.5 ± 1.44 μm thickness) with a smooth and even surface and a cross-sectional structure. The incorporation of NC1 improves the quality of the film by enhancing its mechanical strength and thermal stability. FT-IR spectra showed the successful interaction between chitosan and alginate in the LBL assembly and the incorporation of NC1 in the alginate layer. The red meat preservation test demonstrated that the shelf life improved when the meat was covered with the fabricated bio-based film. The color of the meat was retained for up to 7 days compared to that of the control (Chi alone and Chi + Alg). Additionally, a reduction in the microbial count in the Chi + Alg + NC1 film was observed, corroborating the shelf-life improvement. In addition to its inherent antimicrobial properties, NC1 induced hydrophilic properties to the film, which further aids in its antimicrobial activity against E. coli. These findings suggest that Chi + Alg + NC1 film could be a potent alternative to plastic packaging and can be used as a cling film to prolong the shelf life of red meat.

A review of emerging applications of ultrasonication in Comparison with non-ionizing technologies for meat decontamination

Meat is highly susceptible to contamination with harmful microorganisms throughout the production, processing, and storage chain, posing a significant public health risk. Traditional decontamination methods like chemical sanitizers and heat treatments often compromise meat quality, generate harmful residues, and require high energy inputs. This necessitates the exploration of alternative non-ionizing technologies for ensuring meat safety and quality. This review provides a comprehensive analysis of the latest advancements, limitations, and future prospects of non-ionizing technologies for meat decontamination, with a specific focus on ultrasonication. It further investigates the comparative advantages and disadvantages of ultrasonication against other prominent non-ionizing technologies such as microwaves, ultraviolet (UV) light, and pulsed light. Additionally, it explores the potential of integrating these technologies within a multi-hurdle strategy to achieve enhanced decontamination across the meat surface and within the matrix. While non-ionizing technologies have demonstrated promising results in reducing microbial populations while preserving meat quality attributes, challenges remain. These include optimizing processing parameters, addressing regulatory considerations, and ensuring cost-effectiveness for large-scale adoption. Combining these technologies with other methods like antimicrobial agents, packaging, and hurdle technology holds promise for further enhancing pathogen elimination while safeguarding meat quality.

Principles and Applications of Non-Thermal Technologies for Meat Decontamination

Meat contains high-value protein compounds that might degrade as a result of oxidation and microbial contamination. Additionally, various pathogenic and spoilage microorganisms can grow in meat. Moreover, contamination with pathogenic microorganisms above the infectious dose has caused foodborne illness outbreaks. To decrease the microbial population, traditional meat preservation methods such as thermal treatment and chemical disinfectants are used, but it may have limitations for the maintenance of meat quality or the consumers acceptance. Thus, non-thermal technologies (e.g., high-pressure processing, pulsed electric field, non-thermal plasma, pulsed light, supercritical carbon dioxide technology, ozone, irradiation, ultraviolet light, and ultrasound) have emerged to improve the shelf life and meat safety. Non-thermal technologies are becoming increasingly important because of their advantages in maintaining low temperature, meat nutrition, and short processing time. Especially, pulsed light and pulsed electric field treatment induce few sensory and physiological changes in high fat and protein meat products, making them suitable for the application. Many research results showed that these non-thermal technologies may keep meat fresh and maintain heat-sensitive elements in meat products.

A review on plasma-activated water and its application in the meat industry

Meat is a nutritious food with a short shelf life, making it challenging to ensure safety, quality, and nutritional value. Foodborne pathogens and oxidation are the main concerns that lead to health risks and economic losses. Conventional approaches like hot water, steam pasteurization, and chemical washes for meat decontamination improve safety but cause nutritional and quality issues. Plasma-activated water (PAW) is a potential alternative to thermal treatment that can reduce oxidation and microbial growth, an essential factor in ensuring safety, quality, and nutritional value. This review explores the different types of PAW and their physiochemical properties. It also outlines the reaction pathways involved in the generation of short-lived and long-lived reactive nitrogen and oxygen species (RONS) in PAW, which contribute to its antimicrobial abilities. The review also highlights current studies on PAW inactivation against various planktonic bacteria, as well as critical processing parameters that can improve PAW inactivation efficacy. Promising applications of PAW for meat curing, thawing, and decontamination are discussed, with emphasis on the need to understand how RONS in PAW affect meat quality. Recent reports on combining PAW with ultrasound, mild heating, and non-thermal plasma to improve inactivation efficacy are also presented. Finally, the need to develop energy-efficient systems for the production and scalability of PAW is discussed for its use as a potential meat disinfectant without compromising meat quality.

Effect of UV-C followed by storage on the fungal growth and aflatoxins content and storability characteristics of sesame (Sesamum indicum) seeds

Background

UV-C has been suggested as an alternative technology in controlling food spoilage by primary and secondary pests. Its effects on the storability characteristics of sesame seeds during storage were evaluated.

Methods

The UV-C (0, 2.5, 5.0 and 10 kJ m^-2) was applied to explore its Effect on the fungal growth, aflatoxin content, water activity (a_w), colour and free fatty acid content (FFA) of sesame seeds.

Results

Applying the UV-C caused a significant reduction in the fungal growth, a_w, and the lightness (L* value) of sesame seeds in fresh and stored samples. However, significant increases (p < 0.05) in a* and b* values and the FFA of the sesame seeds were observed. Interestingly, the aflatoxins were not detected in the UVC-treated seeds even after storage for 12 months. The Partial Least Squares regression (PLS) analysis indicated that the application of 5.0 kJ m^-2 followed by six months of storage reveals the greatest valid dose for UV-C treatments of sesame seeds.

Conclusion

UV-C treatment potentially shows effective quarantine security as an alternative method to chemical disinfection procedures to prolong the shelf life and improve the storability characteristics of sesame seeds.

Antimicrobial activities of emulsion-based edible solutions incorporating lemon essential oil and sodium caseinate against some food-borne bacteria

The antimicrobial properties of two different emulsion formulations contained lemon essential oil (coarse emulsion; CE and nanoemulsion; NE) and emulsions based edible solutions incorporated with lemon essential oil and sodium caseinate (coarse emulsion based solution; CESC and nanoemulsion based solution; NESC) on food-related microorganisms (Photobacterium damselae, Pseudomonas luteola, Salmonella Paratyphi A NCTC13, and Listeria monocytogenes ATCC19112) were investigated. The chemical compositions of lemon essential oils were identified by GC-MS. Physical parameter of different formulations was also analyzed at different time intervals. The antimicrobial properties of solutions were determined by using well diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration, and time-kill assay. The major identified component in lemon essential oil was D limonene (38.38%). NE showed a stronger antimicrobial effect against S. Paratyphi A and L. monocytogenes with 36.50 and 38.75 mm diameter zone compared to all other formulations. Listeria monocytogenes had the highest sensitivity towards NE and NESC formulations with 3.12 mg/ml MIC values in comparison to other two formulations. The nanoemulsion and nanoemulsion based coating solution were more effective than other formulations in killing bacterial cell within a short period time.

Preharvest Management and Postharvest Intervention Strategies to Reduce Escherichia coli Contamination in Goat Meat: A Review

Simple Summary

Goat farms and processing facilities worldwide are primarily small-scale, limited resource operations. Cost-effectiveness and practicality are critical factors to be considered before adopting any pre- and/or post-harvest strategies for pathogen reduction in goat meat. Preharvest management methods in goats that can reduce Escherichia coli in meat include minimizing animal stress, selecting diets and feed deprivation times that can reduce fecal shedding of bacteria, and adding tannin-rich feed supplements. In addition, use of appropriate postharvest nonthermal intervention technologies that can reduce microbial loads in carcasses and meat can extend the shelf-life and marketability of goat meat products. Reducing stress prior to slaughter and using nonthermal intervention methods can result in better meat quality and economic returns for producers.

Abstract

Goat meat is the main source of animal protein in developing countries, particularly in Asia and Africa. Goat meat consumption has also increased in the US in the recent years due to the growing ethnic population. The digestive tract of goat is a natural habitat for Escherichia coli organisms. While researchers have long focused on postharvest intervention strategies to control E. coli outbreaks, recent works have also included preharvest methodologies. In goats, these include minimizing animal stress, manipulating diet a few weeks prior to processing, feeding diets high in tannins, controlling feed deprivation times while preparing for processing, and spray washing goats prior to slaughter. Postharvest intervention methods studied in small ruminant meats have included spray washing using water, organic acids, ozonated water, and electrolyzed water, and the use of ultraviolet (UV) light, pulsed UV-light, sonication, low-voltage electricity, organic oils, and hurdle technologies. These intervention methods show a strong antimicrobial activity and are considered environmentally friendly. However, cost-effectiveness, ease of application, and possible negative effects on meat quality characteristics must be carefully considered before adopting any intervention strategy for a given meat processing operation. As discussed in this review paper, novel pre- and post-harvest intervention methods show significant potential for future applications in goat farms and processing plants.

Optimization of UV-C light and lactic acid combined treatment in decontamination of sliced Brazilian dry-cured loin: Salmonella Typhimurium inactivation and physicochemical quality

This study aimed to test the effect of UV-C light (0.01-0.64 J/cm²) (UV) and lactic acid (0.1-12.9%) (LA) combined treatment on sliced Brazilian dry-cured loin (Socol, BDL) for (i) Salmonella Typhimurium reduction, (ii) physicochemical changes (color (a*, cured color, and ΔE), protein and lipid oxidation) and (iii) optimization using response surface methodology (RSM). Linear inactivation rate was achieved and UV was 2-fold more efficient than LA to inactivate S. Typhimurium. At the same time these combined technologies increased lipid (linear rate, R²_adj = 0.88), protein oxidation (quadratic rate, R²_adj = 0.86) and meat discoloration. Furthermore, the minimum point of the physicochemical changes was obtained using RSM, and the decontamination process was optimized. Hence, a reduction of 1.3 log cfu/g was achieved using 0.36 J/cm² of UV and 7.7% of LA. These combined methods represent a promising industrial intervention strategy to dry-meat safety and quality.

Synthesis and evaluation of highly dispersible and efficient photocatalytic TiO2/poly lactic acid nanocomposite films via sol-gel and casting processes

Using titanium teraisopropoxide (TTIP) as the hydrolysis material, titanium dioxide (TiO₂) (6.3-11.1 nm) nanoparticles were synthesized via the sol-gel method and reinforced into poly lactic acid (PLA)/TiO₂ nanocomposite films by casting. The effect of increasing amounts of TiO₂ on the structure and properties of PLA/TiO₂ nanocomposite films were evaluated. These results indicated that self-aggregation of TiO₂ nanoparticles in PLA films could be avoided via sol-gel and casting processes. The presence of TiO₂ significantly improved the tensile strength and thermal stability of films. The PLA/TiO₂ (0.6 wt%) film exhibited the highest photocatalytic activity efficiency under UV irradiation and displayed high antibacterial activities with optimal inhibition zones of Staphylococcus aureus, followed by Escherichia dispersibility of TiO₂ in films were responsible for those improvements. This study suggests that PLA/TiO₂ nanocomposite films could be a promising antimicrobial alternative material to conventional plastic packages.

Evaluation of Probiotic-Beverage Matrix Interaction for Efficient Control of Enterobacter aerogenes and Staphylococcus aureus

HIGHLIGHTS

L. rhamnosus GG in sea buckthorn matrix inhibited E. aerogenes and S. aureus. L. rhamnosus GG was more efficient in sea buckthorn than in apple matrix. Enhanced protection in sea buckthorn matrix may be due to higher phenolic content. WPC and the probiotic increased the pseudoplasticity of the juice matrices.

Development of small blood volume assays for the measurement of oxidative stress markers in mammals

Measuring oxidative stress has become increasingly valuable in ecological studies, especially when different markers are measured on the same individual. However, many of the current methods lack sensitivity for analysis of low blood volume samples, which represent a challenge for longitudinal field studies of small organisms. Small blood volumes can usually only be analysed by using a single assay, therefore providing limited information on individual's oxidative profile. In this study, we used blood collected from a population of wild eastern chipmunks (Tamias striatus) and modified methods presented in the literature to improve analytical selectivity and sensitivity required for small blood volumes. Specifically, we proposed a modified malondialdehyde (MDA) analysis protocol by HPLC and also optimized both the uric acid independent ferric reducing antioxidant power (FRAP) and hypochlorous acid shock capacity (HASC) assays. Development of the three modified methods was achieved with a sensitivity and repeatability that meets standards of field ecology while allowing measurement of all three assays in duplicate using less than 60 μL of plasma. Availability of these tests using small blood volumes will provide ecologists with a more comprehensive portrait of an individual's oxidative profile and a better understanding of its determinants and interactions with the environment.