Processing interventions for enhanced microbiological safety of beef carcasses and beef products: A review

Chilled beef is inevitably contaminated with microorganisms, starting from the very beginning of the slaughter line. A lot of studies have aimed to improve meat safety and extend the shelf life of chilled beef, of which some have focused on improving the decontamination effects using traditional decontamination interventions, and others have investigated newer technologies and methods, that offer greater energy efficiency, lower environmental impacts, and better assurances for the decontamination of beef carcasses and cuts. To inform industry, there is an urgent need to review these interventions, analyze the merits and demerits of each technology, and provide insight into 'best practice' to preserve microbial safety and beef quality. In this review, the strategies and procedures used to inhibit the growth of microorganisms on beef, from slaughter to storage, have been critiqued. Critical aspects, where there is a lack of data, have been highlighted to help guide future research. It is also acknowledge that different intervention programs for microbiological safety have different applications, dependent on the initial microbial load, the type of infrastructures, and different stages of beef processing.

Electrolyzed water produced using carbon electrodes promotes the proliferation of normal cells while inhibiting cancer cells

We previously developed electrolyzed water (EW) using carbon electrodes and estimated its ability to inhibit the proliferation of human cervical carcinoma HeLa cells. In this study, we found that EW-containing media could not only inhibit HeLa cell proliferation, but were also capable of promoting the proliferation of normal human dermal fibroblasts (NHDF). In addition, the developed EW could reduce cytochrome c, as demonstrated by the cytochrome c reduction assay. Interestingly, EW with a greater pH, which was unable to inhibit HeLa cell proliferation, completely lost the ability to reduce cytochrome c. Our results indicate that EW has opposite effects on cancer and normal cell proliferation and has the ability to reduce cytochrome c. Based on our findings, we suggest the possibility that the reducing capacity of our developed EW may be involved in the significant inhibition of HeLa cell proliferation.

Antiseptic Effects and Biosafety of a Controlled-Flow Electrolyzed Acid Solution Involve Electrochemical Properties, Rather than Free Radical Presence

Electrolyzed acid solutions produced by different methods have antiseptic properties due to the presence of chlorine and reactive oxygen species. Our aim was to determine whether a controlled-flow electrolyzed acid solution (CFEAS) has the ability to improve wound healing due to its antiseptic and antibiofilm properties. First, we demonstrated in vitro that Gram-negative and Gram-positive bacteria were susceptible to CFEAS, and the effect was partially sustained for 24 h, evidencing antibiofilm activity (p < 0.05, CFEAS-treated vs. controls). The partial cytotoxicity of CFEAS was mainly observed in macrophages after 6 h of treatment; meanwhile, fibroblasts resisted short-lived free radicals (p < 0.05, CFEAS treated vs. controls), perhaps through redox-regulating mechanisms. In addition, we observed that a single 24 h CFEAS treatment of subacute and chronic human wounds diminished the CFU/g of tissue by ten times (p < 0.05, before vs. after) and removed the biofilm that was adhered to the wound, as we observed via histology from transversal sections of biopsies obtained before and after CFEAS treatment. In conclusion, the electrolyzed acid solution, produced by a novel method that involves a controlled flow, preserves the antiseptic and antibiofilm properties observed in other, similar formulas, with the advantage of being safe for eukaryotic cells; meanwhile, the antibiofilm activity is sustained for 24 h, both in vitro and in vivo.

Postharvest processing of tree nuts: Current status and future prospects-A comprehensive review

Tree nuts are important economic crops and are consumed as healthy snacks worldwide. In recent years, the increasing needs for more efficient and effective postharvest processing technologies have been driven by the growing production, higher quality standards, stricter food safety requirements, development of new harvesting methods, and demand to achieve energy saving and carbon neutralization. Among all, the technologies related to drying, disinfection, and disinfestation and downstream processes, such as blanching, kernel peeling, and roasting, are the most important processes influencing the quality and safety of the products. These processes make up the largest contribution to the energy consumptions and environmental impacts stemming from tree nut production. Although many studies have been conducted to improve the processing efficiency and sustainability, and preserve the product quality and safety, information from these studies is fragmented and a centralized review highlighting the important technology advancements of postharvest processing of tree nuts would benefit the industry. In this comprehensive review, almonds, walnuts, and pistachios are selected as the representative crops of tree nuts. Current statuses, recent advances, and ongoing challenges in the scientific research as well as in the industrial processing practices of these tree nuts are summarized. Some new perspectives and applications of tree nut processing waste and by-products (such as the hulls and shells) are also discussed. In addition, future trends and research needs are highlighted. The material presented here will help both stakeholders and scientists to better understand postharvest tree nut processing and provide technological recommendations to improve the efficiency and sustainability, product quality and safety, and competitiveness of the industry.

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.

Kinetic Modeling of Slightly Acidic Electrolyzed Water Decay Characteristics in Fresh Cabbage Disinfection Against Human Norovirus

To consistently disinfect fresh vegetables efficiently, the decay of disinfectants such as chlorine, electrolyzed oxidizing water (EOW), ozonated water, and plasma-activated water during the disinfection maintenance stage needs to be understood. The aim of our study was to evaluate the changes in the inactivation kinetics of slightly acidic electrolyzed water (SAEW) against human norovirus (HuNoV), based on the cabbage-to-SAEW ratio. After disinfection of fresh cabbage with disinfected SAEW solution, SAEW samples were collected and analyzed for physicochemical properties such as pH, available chlorine concentrations (ACCs), and oxidation-reduction potential (ORP). SAEW virucidal effects were evaluated. We confirmed the decay of post-disinfection SAEW solution and demonstrated the different patterns of the decay kinetic model for HuNoV GI.6 and GII.4. In addition, the goodness of fit of the tested models based on a lower Akaike information criterion, root-mean-square error (RMSE), and residual sum of squares (RSS) was close to zero. In particular, the change in both the HuNoV GI.6 and GII.4 inactivation exhibited a strong correlation with the changes in the ACC of post-disinfection SAEW. These findings demonstrate that physicochemical parameters of SAEW play a key role in influencing the kinetic behavior of changes in the disinfection efficiency of SAEW during the disinfection process. Therefore, to optimize the efficiency of SAEW, it is necessary to optimize the produce-to-SAEW ratio in future studies.

Emerging Technologies for Aerial Decontamination of Food Storage Environments to Eliminate Microbial Cross-Contamination

Air is recognized as an important source of microbial contamination in food production facilities and has the potential to contaminate the food product causing food safety and spoilage issues for the food industry. Potential for aerial microbial contamination of food can be a particular issue during storage in cold rooms when the food is not packaged and is exposed to contaminated air over a prolonged period. Thus, there are potential benefits for the food industry for an aerial decontamination in cold storage facilities. In this paper, aerial decontamination approaches are reviewed and challenges encountered for their applications are discussed. It is considered that current systems may not be completely effective and environmentally friendly, therefore, it is of great significance to consider the development of nonresidual and verified decontamination technologies for the food industry and, in particular, for the cold storage rooms.

Optimization of Electrolysis Parameters for Green Sanitation Chemicals Production Using Response Surface Methodology

Electrolyzed water (EW) shows great potential as a green and economical sanitation solution for the food industry. However, only limited studies have investigated the optimum electrolysis parameters and the bactericidal effect of acidic electrolyzed water (AcEW) and alkaline electrolyzed water (AlEW). Here, the Box–Behnken experimental design was used to identify the optimum parameters. The tests were conducted with different types of electrodes, electrical voltages, electrolysis times, and NaCl concentrations. There were no obvious differences observed in the physico-chemical properties of EW when different electrodes were used. However, stainless steel was chosen as it meets most of the selection criteria. The best-optimized conditions for AcEW were at 11.39 V, 0.65 wt.% NaCl, and 7.23 min, while the best-optimized conditions for AlEW were at 10.32 V, 0.6 wt.% NaCl, and 7.49 min. The performance of the optimum EW (AcEW and AlEW) compared with commercial cleaning detergents for the food industry was then evaluated. The bactericidal activity of AcEW and AlEW was examined against Escherichia coli ATCC 10536 at different temperatures (30 °C and 50 °C) for 30 s. The results show that both AcEW and AlEW have the ability to reduce the Escherichia coli to non-detectable levels (less than 2 log CFU/mL).

Applications of Electrolyzed Water as a Sanitizer in the Food and Animal-By Products Industry

Food demand is increasing every year and, usually animal-derived products are generated far from consumer-places. New technologies are being developed to preserve quality characteristics during processing and transportation. One of them is electrolyzed water (EW) that helps to avoid or decrease the development of foodborne pathogens, or losses by related bacteria. Initially, EW was used in ready-to-eat foods such as spinach, lettuce, strawberries, among others; however, its application in other products is under study. Every product has unique characteristics that require an optimized application of EW. Different sanitizers have been developed; unfortunately, they could have undesirable effects like deterioration of quality or alterations in sensory properties. Therefore, EW is gaining popularity in the food industry due to its characteristics: easy application and storage, no corrosion of work surfaces, absence of mucosal membrane irritation in workers handling food, and it is considered environmentally friendly. This review highlights the advantages of using EW in animal products like chicken, pork, beef, eggs and fish to preserve their safety and quality.

Emerging chemical and physical disinfection technologies of fruits and vegetables: a comprehensive review

With a growing demand for safe, nutritious, and fresh-like produce, a number of disinfection technologies have been developed. This review comprehensively examines the working principles and applications of several emerging disinfection technologies. The chemical treatments, including chlorine dioxide, ozone, electrolyzed water, essential oils, high-pressure carbon dioxide, and organic acids, have been improved as alternatives to traditional disinfection methods to meet current safety standards. Non-thermal physical treatments, such as UV-light, pulsed light, ionizing radiation, high hydrostatic pressure, cold plasma, and high-intensity ultrasound, have shown significant advantages in improving microbial safety and maintaining the desirable quality of produce. However, using these disinfection technologies alone may not meet the requirement of food safety and high product quality. Several hurdle technologies have been developed, which achieved synergistic effects to maximize lethality against microorganisms and minimize deterioration of produce quality. The review also identifies further research opportunities for the cost-effective commercialization of these technologies.

The effect of neutral electrolyzed water as a disinfectant of eggshells artificially contaminated with Listeria monocytogenes

Neutral electrolyzed water (NEW) was tested as a disinfectant against Listeria monocytogenes on the surface of table eggs. Eggs were collected from a single Bovans White flock and were exposed to L. monocytogenes. Artificially contaminated eggs were divided into three different treatment groups: NEW, 2% citric acid solution (CAS), and saline solution (SS). To evaluate the bactericidal effect, the Mexican norm for antimicrobial activity determination protocol was performed. The observed bactericidal effect was compared against those obtained from CAS and SS. Bacterial cells present on the eggshells were quantified. NEW exhibited a significantly higher bactericidal effect than CAS when evaluated on the surfaces of chicken eggshells (6.11 log10CFU/ml reduction in vitro and a 2.18 log10 CFU/egg reduction on eggs vs. 1.06 log10CFU/ml in vitro reduction and 1.74 log10CFU/egg). Additionally, CAS was found to react with the carbonate egg shield, resulting in a loss of cuticle integrity. Mineral content of NEW-treated eggshells was similar to SS-treated eggshells; however, CAS-treated eggshells showed a significant decrease in phosphorous concentration compared to NEW treatment. In this study, we demonstrated the effect of NEW and CAS on the integrity of the L. monocytogenes wall using transmission electron microscopy. To the best of our knowledge, this is the first report of the effect of NEW against L. monocytogenes on eggshells. Our results show that NEW is a viable alternative solution for the disinfection of table eggs that does not affect the cuticle or shell.

Novel approaches for chemical and microbiological shelf life extension of cereal crops

Economic losses due to post-harvest fungal spoilage and mycotoxin contamination of cereal crops is a frequently encountered issue. Typically, chemical preservatives are used to reduce the initial microbial load and the environmental conditions during storage are controlled to prevent microbial growth. However, in recent years the consumers' desire for more naturally produced foods containing less chemical preservatives has grown increasingly stronger. This article reviews the latest advances in terms of novel approaches for chemical decontamination, namely application cold atmospheric pressure plasma and electrolyzed water, and their suitability for preservation of stored cereal crops. In addition, the alternative use of bio-preservatives, such as starter cultures or purified antimicrobial compounds, to prevent the growth of spoilage organisms or remove in-field accumulated mycotoxins is evaluated. All treatments assessed here show potential for inhibition of microbial spoilage. However, each method encounters draw-backs, making industrial application difficult. Even under optimized processing conditions, it is unlikely that one single treatment can reduce the natural microbial load sufficiently. It is evident that future research needs to examine the combined application of several treatments to exploit their synergistic properties. This would enable sufficient reduction in the microbial load and ensure microbiological safety of cereal crops during long-term storage.

Cytotoxicity, Bactericidal, and Antioxidant Activity of Sodium Alginate Hydrosols Treated with Direct Electric Current

The aim of the study was to investigate the effect of using direct electric current (DC) of 0, 200, and 400 mA for five minutes on the physiochemical properties, cytotoxicity, antibacterial, and antioxidant activity of sodium alginate hydrosols with different sodium chloride concentrations. The pH, oxidation-reduction potential (ORP), electrical conductivity (EC), and available chlorine concentration (ACC) were measured. The effect of sodium alginate hydrosols treated with DC on Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Micrococcus luteus, Escherichia coli, Salmonella enteritidis, Yersinia enterocolitica, Pseudomonas fluorescence, and RAW 264.7 and L929 cells was investigated. Subsequently, the antioxidant properties of hydrosols were evaluated by determining the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) and ferric reducing antioxidant power (FRAP). The results have shown that after applying 400 mA in hydrosol samples with 0.1% and 0.2% NaCl all tested bacteria were inactivated. The ACC concentration of C400 samples with NaCl was equal to 13.95 and 19.71 mg/L, respectively. The cytotoxicity analysis revealed that optimized electric field conditions and the addition of sodium chloride allow for the avoidance of toxicity effects on normal cells without disturbing the antibacterial effects. Due to the presence of oxidizing substances, the DPPH of variants treated with DC was lower than the DPPH of control samples.

Suitability of electrolyzed oxidizing water for the disinfection of hard surfaces and equipment in radiology

BACKGROUND

Hospitals are faced with increasingly resistant strains of micro-organisms. When it comes to disinfection, individual parts of electronic equipment of angiology diagnostics such as patient couches of computer tomography (CT) and magnetic resonance imaging (MRI) scanners prove to be very hard to disinfect. Disinfectants of choice are therefore expected to possess properties such as rapid, residue-free action without any damaging effect on the sensitive electronic equipment. This paper discusses the use of the neutral electrolyzed oxidizing water (EOW) as a biocide for the disinfection of diagnostic rooms and equipment.

METHODS

The CT and MRI rooms were aerosolized with EOW using aerosolization device. The presence of micro-organisms before and after the aerosolization was recorded with the help of sedimentation and cyclone air sampling. Total body count (TBC) was evaluated in absolute and log values.

RESULTS

The number of micro-organisms in hospital rooms was low as expected. Nevertheless, a possible TBC reduction between 78.99-92.50% or 50.50-70.60% in log values was recorded.

CONCLUSIONS

The research has shown that the use of EOW for the air and hard surface disinfection can considerably reduce the presence of micro-organisms and consequently the possibility of hospital infections. It has also demonstrated that the sedimentation procedure is insufficient for the TBC determination. The use of Biocide aerosolization proved to be efficient and safe in all applied ways. Also, no eventual damage to exposed devices or staff was recorded.

Physicochemical Properties of Edible Chitosan/Hydroxypropyl Methylcellulose/Lysozyme Films Incorporated with Acidic Electrolyzed Water

The treatment with acidic electrolyzed water (AEW) is a promising disinfection method due to its effectiveness in reducing microbial population. The aim of the study was to evaluate physicochemical properties of chitosan/HPMC films incorporated with lysozyme and acidic electrolyzed water. In the composite films, decreasing film solubility and increasing concentration of sodium chloride solution and prolongation of electrolysis time were observed. Electrolysis process with sodium chloride induces spongy network of film structure. The use of AEW has not changed chemical composition of films which was proved by1H NMR, MALDI-TOF, and FT-IR spectroscopy. The research confirmed that electrolysis significantly improved thermomechanical properties of the examined films. The contact angle values of the films were quite similar and ranged between 56° and 73°. The increase of salt concentration used in the electrolysis process had an impact on increasing flexibility of samples. Application of electrolyzed water in commonly used food processing systems is possible. Fusion of AEW and biopolymers may provide better integration with coated food product and multidirectional protecting effect.