Use of power ultrasound to enhance the thermal inactivation of Clostridium perfringens spores in beef slurry

Impact of pH and High-Pressure Pasteurization on the Germination and Development of Clostridium perfringens Spores under Hyperbaric Storage versus Refrigeration

This study aimed to evaluate hyperbaric storage at room temperature (75-200 MPa, 30 days, 18-23 °C, HS/RT) on Clostridium perfringens spores in brain-heart infusion broth (BHI-broth) at pH 4.50, 6.00, and 7.50 and coconut water (pH 5.40). Both matrices were also pasteurized by high pressure processing (600 MPa, 3 min, 17 °C, HPP) to simulate commercial pasteurization followed by HS, in comparison with refrigeration (5 °C, RF). The results showed that, at AP/RT, spores' development occurred, except at pH 4.50 in BHI-broth, while for RF, no changes occurred along storage. Under HS, at pH 4.50, neither spore development nor inactivation occurred, while at pH 6.00/7.50, inactivation occurred (≈2.0 and 1.0 logs at 200 MPa, respectively). Coconut water at AP/RT faced an increase of 1.6 logs of C. perfringens spores after 15 days, while for RF, no spore development occurred, while the inactivation of spores under HS happened (≈3 logs at 200 MPa). HPP prior to HS seems to promote a subsequent inactivation of C. perfringens spores in BHI-broth at pH 4.50, which is less evident for other pHs. For HPP coconut water, the inactivation levels under HS were lower (≈2.0 logs at 200 MPa). The Weibull model well described the inactivation pattern observed. These results suggest that HS/RT can be simultaneously used as a tool to avoid C. perfringens spores' development, as well as for its inactivation, without the application of high temperatures that are required to inactivate these spores.

Recent developments in ultrasound approach for preservation of animal origin foods

Ultrasound is a contemporary non-thermal technology that is currently being extensively evaluated for its potential to preserve highly perishable foods, while also contributing positively to the economy and environment. There has been a rise in the demand for food products that have undergone minimal processing or have been subjected to non-thermal techniques. Livestock-derived food products, such as meat, milk, eggs, and seafood, are widely recognized for their high nutritional value. These products are notably rich in proteins and quality fats, rendering them particularly vulnerable to oxidative and microbial spoilage. Ultrasound has exhibited significant antimicrobial properties, as well as the ability to deactivate enzymes and enhance mass transfer. The present review centers on the production and classification of ultrasound, as well as its recent implementation in the context of livestock-derived food products. The commercial applications, advantages, and limitations of the subject matter are also subject to scrutiny. The review indicated that ultrasound technology can be effectively utilized in food products derived from livestock, leading to favorable outcomes in terms of prolonging the shelf life of food while preserving its nutritional, functional, and sensory attributes. It is recommended that additional research be conducted to investigate the effects of ultrasound processing on nutrient bioavailability and extraction. The implementation of hurdle technology can effectively identify and mitigate the lower inactivation of certain microorganisms or vegetative cells.

Assessment on the efficacy of methods 2 to 5 and method 7 set out in Commission Regulation (EU) No 142/2011 to inactivate relevant pathogens when producing processed animal protein of porcine origin intended to feed poultry and aquaculture animals

An assessment was conducted on the level of inactivation of relevant pathogens that could be present in processed animal protein of porcine origin intended to feed poultry and aquaculture animals when methods 2 to 5 and method 7, as detailed in Regulation (EU) No 142/2011, are applied. Five approved scenarios were selected for method 7. Salmonella Senftenberg, Enterococcus faecalis, spores of Clostridium perfringens and parvoviruses were shortlisted as target indicators. Inactivation parameters for these indicators were extracted from extensive literature search and a recent EFSA scientific opinion. An adapted Bigelow model was fitted to retrieved data to estimate the probability that methods 2 to 5, in coincidental and consecutive modes, and the five scenarios of method 7 are able to achieve a 5 log10 and a 3 log10 reduction of bacterial indicators and parvoviruses, respectively. Spores of C. perfringens were the indicator with the lowest probability of achieving the target reduction by methods 2 to 5, in coincidental and consecutive mode, and by the five considered scenarios of method 7. An expert knowledge elicitation was conducted to estimate the certainty of achieving a 5 log10 reduction of spores of C. perfringens considering the results of the model and additional evidence. A 5 log10 reduction of C. perfringens spores was judged: 99-100% certain for methods 2 and 3 in coincidental mode; 98-100% certain for method 7 scenario 3; 80-99% certain for method 5 in coincidental mode; 66-100% certain for method 4 in coincidental mode and for method 7 scenarios 4 and 5; 25-75% certain for method 7 scenario 2; and 0-5% certain for method 7 scenario 1. Higher certainty is expected for methods 2 to 5 in consecutive mode compared to coincidental mode.

New Thoughts on an Old Topic: Secrets of Bacterial Spore Resistance Slowly Being Revealed

The quest for bacterial survival is exemplified by spores formed by some Firmicutes members. They turn up everywhere one looks, and their ubiquity reflects adaptations to the stresses bacteria face. Spores are impactful in public health, food safety, and biowarfare. Heat resistance is the hallmark of spores and is countered principally by a mineralized gel-like protoplast, termed the spore core, with reduced water which minimizes macromolecular movement/denaturation/aggregation. Dry heat, however, introduces mutations into spore DNA. Spores have countermeasures to extreme conditions that are multifactorial, but the fact that spore DNA is in a crystalline-like nucleoid in the spore core, likely due to DNA saturation with small acid-soluble spore proteins (SASPs), suggests that reduced macromolecular motion is also critical in spore dry heat resistance. SASPs are also central in the radiation resistance characteristic of spores, where the contributions of four spore features-SASP; Ca2+, with pyridine-2,6-dicarboxylic acid (CaDPA); photoproduct lyase; and low water content-minimize DNA damage. Notably, the spore environment steers UV photochemistry toward a product that germinated spores can repair without significant mutagenesis. This resistance extends to chemicals and macromolecules that could damage spores. Macromolecules are excluded by the spore coat which impedes the passage of moieties of ≥10 kDa. Additionally, damaging chemicals may be degraded or neutralized by coat enzymes/proteins. However, the principal protective mechanism here is the inner membrane, a compressed structure lacking lipid fluidity and presenting a barrier to the diffusion of chemicals into the spore core; SASP saturation of DNA also protects against genotoxic chemicals. Spores are also resistant to other stresses, including high pressure and abrasion. Regardless, overarching mechanisms associated with resistance seem to revolve around reduced molecular motion, a fine balance between rigidity and flexibility, and perhaps efficient repair.

A new decontamination method for Bacillus subtilisin pasteurized milk: Thermosonication treatment

Thermosonication (TS) is a novel and viable technique employed to replace conventional thermal processing. TS treatment combined with pasteurization was used to kill the residual heat-resistant Bacillus in pasteurized milk and extend the shelf life of pasteurized milk and compared with High Temperture Shoort Time (HTST) pasteurization to study its decontamination effect on Bacillus subtilis and the quality of treated milk. The results showed that after 40 kHz, 240 W, 25 min ultrasonic treatment and 50 °C heating decontamination treatment, the number of B. subtilis in the medium and milk medium decreased by 4.17 log CFU/mL and 4.09 log CFU/mL respectively. The results of cell membrane permeability showed that the leakage of DNA and protein in the HTST-TS group increased by 52.3 % and 34 %, respectively, when compared to that in the HTST group. In addition, transmission electron microscopy (TEM) analysis showed that the bacterial cell membrane of the HTST-TS group swelled up, the cell wall was ruptured, and the cell content was accumulated in the cells. The results showed that HTST-TS treatment significantly inhibited the activities of ATPase (47 %), succinate dehydrogenase (SDH) (68.6 %), and malate dehydrogenase (MDH) (54.4 %). The physical and chemical sensory evaluation of milk treated with HTST-TS showed that HTST-TS treatment could improve the L* value (2.24 %), zeta potential (64.19 %), and colloidal particle size (14.49 %) of milk but had no significant effect on oral sensitivity. In conclusion, this study provides new insights, which may be helpful in implementing this new combined decontamination method in the dairy industry to improve the quality of pasteurized milk and extend the its shelf life.

The positive contribution of ultrasound technology in muscle food key processing and its mechanism-a review

Traditional processing methods can no longer meet the demands of consumers for high-quality muscle food. As a green and non-thermal processing technology, ultrasound has the advantage of improving processing efficiency and reducing processing costs. Of these, the positive effect of power ultrasound in the processing of muscle foods is noticeable. Based on the action mechanism of ultrasound, the factors affecting the action of ultrasound are analyzed. On this basis, the effect of ultrasound technology on muscle food quality and its action mechanism and application status in processing operations (freezing-thawing, tenderization, marination, sterilization, drying, and extraction) is discussed. The transient and steady-state effects, mechanical effects, thermal effects, and chemical effects can have an impact on processing operations through complex correlations, such as improving the efficiency of mass and heat transfer. Ultrasound technology has been proven to be valuable in muscle food processing, but inappropriate ultrasound treatment can also have adverse effects on muscle foods. In the future, kinetic models are expected to be an effective tool for investigating the application effects of ultrasound in food processing. Additionally, the combination with other processing technologies can facilitate their intensive application on an industrial level to overcome the disadvantages of using ultrasound technology alone.

Ultrasound-Assisted Slightly Acidic Electrolyzed Water in Aquatic Product Sterilization: A Review

Ultrasound has been confirmed as the propagation process of mechanical vibrations in a medium, with a frequency significantly higher than 20 kHz. Moreover, it has an effect of sterilization on foods. In general, ultrasonic sterilization medium is manifested as a liquid. Ultrasonic treatment technology has certain advantages in aquatic product processing. It is noteworthy that this technology will have better effects of sterilization if used in combination with other treatment methods. Slightly acidic electrolyzed water (SAEW) is characterized by high-efficiency broad-spectrum sterilization operation, low cost, and environmental protection, among other properties, and has a positive effect on aquatic product sterilization and preservation. Selecting acidic electrolyzed water with a low concentration coupled with low-power ultrasonic waves for combined sterilization exerts a more potent sterilization effect, and acidic electrolyzed water combined with ultrasonic sterilization is expected to be a potentially environment-friendly alternative. In this study, the sterilization mechanisms of ultrasonic and SAEW methods used both individually and as a synergistic treatment, the effect on microbial growth, and the research progress of the application of the combined effect in the sterilization and refrigeration of aquatic products are reviewed. Furthermore, this study looks forward to the future development trend, with a view to its application in aquatic products, while providing a reference for research and application in the field of processing and safety.

Inactivation of Clostridium perfringens C1 Spores by the Combination of Mild Heat and Lactic Acid

Clostridium perfringens is a major pathogen causing foodborne illnesses. In this experiment, the inactivation effects of heat and lactic acid (LA) treatments on C. perfringens spores was investigated. Heat treatment (80 °C, 90 °C and 100 °C), LA (0.5% and 1%), and combined LA and heat treatments for 30 and 60 min were performed. Residual spore counts showed that the count of C. perfringens spores was below the detection limit within 30 min of treatment with 1% LA and heat treatment at 90 °C. Scanning electron microscopy and confocal scanning laser microscopy results showed that the surface morphology of the spores was severely disrupted by the co-treatment. The particle size of the spores was reduced to 202 nm and the zeta potential to −3.66 mv. The inner core of the spores was disrupted and the co-treatment resulted in the release of 77% of the nuclear contents 2,6-pyridinedicarboxylic acid. In addition, the hydrophobicity of spores was as low as 11% after co-treatment with LA relative to the control, indicating that the outer layer of spores was severely disrupted. Thus, synergistic heating and LA treatment were effective in inactivating C. perfringens spores.

Advances in prepared dish processing using efficient physical fields: A review

Prepared dishes are increasingly popular convenience food that can be eaten directly from hygienic packaging by heating. Physics field (PF) is food processing method built with physical processing technology, which has the characteristics of high efficiency and environmental safety. This review focuses on summarizing the application of PFs in prepared dishes, evaluating and comparing PFs through quality changes during processing and storage of prepared dishes. Currently, improving the quality and extending the shelf life of prepared dishes through thermal and non-thermal processing are the main modes of action of PFs. Most PFs show good potential in handing prepared dishes, but may also react poorly to some prepared dishes. In addition, the difficulty of precise control of processing conditions has led to research mostly at the laboratory stage, but as physical technology continues to break through, more PFs and multi-physical field will be promoted for commercial use in the future. This review contributes to a deeper understanding of the effect of PFs on prepared dishes, and provides theoretical reference and practical basis for future processing research in the development of various enhanced PFs.

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.

Fate of Clostridia and other spore-forming Firmicute bacteria during feedstock anaerobic digestion and aerobic composting

Pathogenic spore-forming Firmicutes are commonly present in animal and human wastes that are used as fertilizers in crop production. Pre-treatments of organic waste prior to land application offer the potential to abate enteric microorganisms, and therefore reduce the risk of contamination of crops or adjacent water resources with pathogens carried in these materials. The inactivation and reduction of gram-positive spore formers such as Clostridium spp., Clostridioides spp. and Bacillus spp. from animal and human waste can be challenging given the recalcitrance of the spores these bacteria produce. Given the significance of these organisms to human and animal health, information concerning spore-forming bacteria inactivation during anaerobic digestion (AD) and aerobic composting (AC) is required as the basis for recommending safe organic waste management practices. In this review, an assessment of the inactivation of spore-forming Firmicutes during AD and AC was conducted to provide guidance for practical management of organic matrices of animal or human origin. Temperature and pH may be the main factors contributing to the inactivation of spore-forming Firmicutes during batch lab-scale AD (log reduction <0.5-5 log). In continuous digesters, wet AD systems do not effectively inactivate spore-forming Firmicutes even under thermopholic conditions (log reduction -1.09 - 0.98), but dry AD systems could be a feasible management practice to inactivate spore-forming Firmicutes from organic materials with high solid content (log reduction 1.77-3.1). In contrast, composting is an effective treatment to abate spore-forming Firmicutes (log reduction 1.7-6.5) when thermophilic conditions last at least six consecutive days. Temperature, moisture content and composting scale are the key operating conditions influencing the inactivation of spore-forming Firmicutes during composting. Where possible, undertaking AD with subsequent composting to ensure the biosafety of digestate before its downstream processing and recycling is recommended to abate recalcitrant bacteria in digestate.

Microbiological Food Safety of Seaweeds

The use of seaweeds in the human diet has a long history in Asia and has now been increasing also in the western world. Concurrent with this trend, there is a corresponding increase in cultivation and harvesting for commercial production. Edible seaweed is a heterogenous product category including species within the green, red, and brown macroalgae. Moreover, the species are utilized on their own or in combinatorial food products, eaten fresh or processed by a variety of technologies. The present review summarizes available literature with respect to microbiological food safety and quality of seaweed food products, including processing and other factors controlling these parameters, and emerging trends to improve on the safety, utilization, quality, and storability of seaweeds. The over- or misuse of antimicrobials and the concurrent development of antimicrobial resistance (AMR) in bacteria is a current worldwide health concern. The role of seaweeds in the development of AMR and the spread of antimicrobial resistance genes is an underexplored field of research and is discussed in that context. Legislation and guidelines relevant to edible seaweed are also discussed.

Proteomic response and molecular regulatory mechanisms of Bacillus cereus spores under ultrasound treatment

This study was aimed at providing new insights on the proteomic response of bacterial spores to ultrasound. Data-independent-acquisition method was used to quantify the proteome change of Bacillus cereus spores after ultrasound treatment (200 W). This study revealed that 2485 proteins were extracted from Bacillus cereus spores, most of them were related to metabolism. After ultrasound treatment, the expression of 340 proteins were significantly changed (the fold change ≥ 2 and p < 0.05), of which 207 proteins were significantly down-regulated. KEGG pathway analysis showed that differentially expressed proteins mainly distributed in metabolism pathway, cell process pathway and genetic information processing pathway after ultrasound treatment. Furthermore, this study analyzed the differentially expressed proteins in significant enrichment pathways. In particular, the expression of key proteins in the phosphorylation reaction of spores was significantly decreased after ultrasound treatment. Thus, ATP synthesis rate decreased and the phosphorylation reaction inhibited. Also, the decrease of the expression of key proteins related to the tricarboxylic acid cycle led to the decrease of nutrients metabolism of spores. Ultrasound treatment induced the down-regulation of fatty acid synthetase expression and promoted fatty acid metabolism at the same time. The content of fatty acids decreased in spores consequently.

Sweet-flavored peptides with biological activities from mulberry seed protein treated by multifrequency countercurrent ultrasonic technology

To increase the reuse of food residues, multifrequency countercurrent ultrasonic treatment was used to enhance the extraction yield of defatted mulberry seed protein (DMSP), and sweet-flavored peptides from DMSP hydrolysates (DMSPHs) were obtained for the first time. Here, the DMSP yield was increased by 16.2% (p < 0.05) while the power density was halved compared with single-frequency ultrasonic treatment. According to Fick's second law, a molecular diffusion dynamics model was developed to be suitable for predicting the pretreatment conditions (R² = 0.9785). After that, the sweet-flavored peptides were purified and the main amino acid sequences were identified, i.e., FEGGSIE, KDFPEAHSQAT, and GSQPAEGAK. Moreover, the antioxidant activities of DMSPHs prepared with tri-frequency treatment was higher than 60%. The DMSPHs retarded the growth of HepG2 cells in vitro, increased the necrotic quadrant (Q1-UL), and extended the S phase. Therefore, the sweet-flavored peptides prepared from DMSPHs using the multifrequency-ultrasonic treatment have significant biological activities.

Recent trends in bacterial decontamination of food products by hurdle technology: A synergistic approach using thermal and non-thermal processing techniques

Researchers are continuously discovering varied technologies for microbial control to ensure worldwide food safety from farm-to-fork. The microbial load and virulence of spoilage causing microorganisms, including bacteria, fungi, yeasts, virus, and protozoa, determines the extent of microbial contamination in a food product. Certain pathogenic microbes can cause food poisoning and foodborne diseases, and adversely affect consumers' health. To erade such food safety-related problems, various traditional and novel food processing methods have been adopted for decades. However, some decontamination techniques bring undesirable changes in food products by affecting their organoleptic and nutritional properties. Combining various thermal and non-thermal food processing methods is an effective way to impart a synergistic effect against food spoilage microorganisms and can be used as an alternative way to combat certain limitations of food processing technologies. The combination of different techniques as hurdles put the microorganisms in a hostile environment and disturbs the homeostasis of microorganisms in food temporarily or permanently. Optimization and globalization of these hurdle combinations is an emerging field in the food processing sector. This review gives an overview of recent inventions in hurdle technology for bacterial decontamination, combining different thermal and non-thermal processing techniques in various food products.

Predictive model for growth of Clostridium perfringens during cooling of cooked pork supplemented with sodium chloride and sodium pyrophosphate

A dynamic model was developed to predict growth of Clostridium perfringens in cooked ground pork supplemented with salt (0-3% wt/wt) and sodium pyrophosphate (0-0.3% wt/wt) under varying temperatures. C. perfringens (NCTC 8238, NCTC 8239, and NCTC 10240) spores were heat shocked, cooled, and inoculated into ground pork. Isothermal bacterial growth was quantified with variable salt and phosphate concentrations at temperatures ranging from 15 to 51 °C. The primary Baranyi model was fitted to all C. perfringens growth profiles and gave a satisfactory fit (R² ≥ 0.85). A quadratic polynomial secondary model was developed (P < 0.0001) to predict the maximum specific growth rate as a function of temperature, salt, and phosphate concentrations (R² = 0.93). A dynamic model was developed and validated using growth data retrieved from 7 published studies. Thirty three out of 44 predictions were within the acceptable prediction zone (-0.5 ≤ prediction error ≤ 1.0). The developed predictive model can be used to minimize the risk of C. perfringens in pork products supplemented with additives during cooling.

Effect of temperature and soluble solid on Bacillus subtilis and Bacillus licheniformis spore inactivation and quality degradation of pineapple juice

Bacillus subtilis and Bacillus licheniformis spores can survive processing temperatures used in the thermal processes of high-acid foods. Therefore, this study investigated the thermal inactivation of B. subtilis and B. licheniformis spores in pineapple juice at different temperatures (85-100°C) and soluble solids (SS, 11-30°Brix). The quality of juices and microbial loads after the thermal treatments during storage at 4 °C for 35 days was then checked. A linear decrease in D-value was observed with increasing temperature of treatment. Furthermore, the D-values determined in pineapple juice were: D_90°C=13.2 ± 0.5 mins, D_95°C = 6.8 ± 0.9 mins and D_100°C = 2.1 ± 1.7 mins for B. subtilis spores, and D_85°C = 16.6 ± 0.4 mins, D_90°C = 7.6 ± 0.5 mins and D_95°C = 3.6 ± 1.5 min, for B. licheniformis. Generally, the susceptibility of the bacteria to soluble solid change was affected by the interaction between temperature, SS and strain. In addition, pasteurization processes of ≥95°C for ≥33.8 mins was needed to ensure a recommended 5-log reduction of B. subtilis spores and limit vitamin C degradation of pineapple juice within three-week of storage at 4 °C.

Selection and application of natural antimicrobials to control Clostridium perfringens in sous-vide chicken breasts inhibition of C. perfringens in sous-vide chicken

Current consumer preferences for both clean label food ingredients and convenience-based foods has provided a unique opportunity to explore the application of novel natural food preservatives in sous vide products. The anaerobic environment and relatively low thermal processing of the sous vide process creates a favorable environment for the survival, germination, and outgrowth of spore-forming bacterium Clostridium perfringens. The aim of this study was to identify effective novel natural ingredient formulations against C. perfringens and apply them within a vacuum-sealed sous vide chicken model exposed to abusive storage and chilling conditions. Among six commercial vinegar-based formulations, liquid vinegar with citrus extract (CE; 1.0%) and with lemon juice concentrate (LJC; 1.5%) were identified as the most effective at inhibiting three individual C. perfringens strains. Both reduced viable cell counts by 5 log CFU/mL (P < 0.05), whereas reductions in spore counts ranged from 2 to 4 log CFU/mL depending on formulation and concentration used. Once incorporated to chicken meat 1.0% CE and 1.5% LJC before sous-vide cooking, completely inhibited the growth of mixed C. perfringens strains (P < 0.05) during storage for 16 days at 12 and 16 °C. Exponential cooling from 54 to 4 °C was performed for 18 h to imitate abusive storage conditions. CE and LJC at 3.0% inhibited growth and reduced counts by 3.4 and 2.9 log CFU/g compared to respective controls. Treatments CE and LJC could be implemented within the formulation of a sous vide chicken product to provide an effective protection against C. perfringens meeting clean label expectations.

Nondestructive monitoring, kinetics and antimicrobial properties of ultrasound technology applied for surface decontamination of bacterial foodborne pathogen in pork

In this study, electronic nose (E-nose) and Hyperspectral Imaging (HSI) was employed for nondestructive monitoring of ultrasound efficiency (20KHZ) in the inactivation of Salmonella Typhimurium, and Escherichia coli in inoculated pork samples treated for 10, 20 and 30 min. Weibull, and Log-linear model fitted well (R2 ≥ 0.9) for both Salmonella Typhimurium, and Escherichia coli inactivation kinetics. The study also revealed that ultrasound has antimicrobial effects on the pathogens. For qualitative analysis, unsupervised (PCA) and supervised (LDA) chemometric algorithms were applied. PCA was used for successful sample clustering and LDA approach was used to construct statistical models for the classification of ultrasound treated and untreated samples. LDA showed classification accuracies of 99.26%,99.63%,99.70%, 99.43% for E-nose - S. Typhimurium, E-nose -E. coli, HSI - S. Typhimurium and HSI -E. coli respectively. PLSR quantitative models showed robust models for S. Typhimurium- (E-nose Rp2 = 0.9375, RMSEP = 0.2107 log CFU/g and RPD = 9.7240 and (HSI Rp2 = 0.9687 RMSEP = 0.1985 log CFU/g and RPD = 10.3217) and E. coli -(E-nose -Rp2 = 0.9531, RMSEP = 0.2057 log CFU/g and RPD = 9.9604) and (HIS- Rp2 = 0.9687, RMSEP = 0.2014 log CFU/g and RPD = 10.1731). This novel study shows the overall effectiveness of applying E-nose and HSI for in-situ and nondestructive detection, discrimination and quantification of bacterial foodborne pathogens during the application of food processing technologies like ultrasound for pathogen inactivation.

Advances in application of ultrasound in food processing: A review

Food processing plays a crucial role in coping up with the challenges against food security by reducing wastage and preventing spoilage. The ultrasound technology has revolutionized the food processing industry with its wide application in various processes, serving as a sustainable and low-cost alternative. This non-destructive technology offers several advantages such as rapid processes, enhanced process efficiency, elimination of process steps, better quality product and retention of product characteristics (texture, nutrition value, organoleptic properties), improved shelf life. This review paper summarizes the various applications of ultrasound in different unit operations (filtration, freezing, thawing, brining, sterilization/pasteurization, cutting, etc.) and specific food divisions (meat, fruits and vegetables, cereals, dairy, etc.) along with, the advantages and drawbacks of the technology. The further scope of industrial implementation of ultrasound has also been discussed.

Application of ultrasound technology in processing of ready-to-eat fresh food: A review

With the increase in food standardization and the pace of modern life, the demand for ready-to-eat foods is growing. The strong processing conditions of traditional technology often accelerate the rate of deterioration of quality, and microbes are the safety hazard of ready-to-eat foods. Ultrasound technology is an environmentally friendly technology that hardly causes thermal damage to raw materials. In this paper, the ultrasound technology is used in the disinfection, sterilization, enzyme inactivation, desensitization, dehydration, curing, tenderization and cooking process of fresh food from the perspective of microbial safety and quality of fresh food. The cavitation effect of ultrasound can improve the mass transfer rate of infiltration processes such as dehydration and curing, promote the oxidation of lipids and proteins for enrich the flavor of meat products, improve the microbiological safety and reduce the sensitization by destroying the integrity of the microbial cells and the conformation of the protein. In addition, ultrasound as an auxiliary processing technology can reduce the damage of traditional production technology to reserve the quality and nutritional value of food. Ultrasound has proved to be an efficient and green processing technology for ready-to-eat food.

Principles and applications of non-thermal technologies and alternative chemical compounds in meat and fish

Conventional methods of food preservation have demonstrated several disadvantages and limitations in the efficiency of the microbial load reduction and maintain food quality. Hence, non-thermal preservation technologies (NTPT) and alternative chemical compounds (ACC) have been considered a high promissory replacer to decontamination, increasing the shelf life and promoting low levels of physicochemical, nutritional and sensorial alterations of meat and fish products. The combination of these methods can be a potential alternative to the food industry. This review deals with the most critical aspects of the mechanisms of action under microbial, physicochemical, nutritional and sensorial parameters and the efficiency of the different NTPT (ultrasound, high pressure processing, gamma irradiation and UV-C radiation) and ACC (peracetic acid, bacteriocins, nanoparticles and essential oils) applied in meat and fish products. The NTPT and ACC present a high capacity of microorganisms inactivation, ensuring low alterations level in the matrix and high reduction of environmental impact. However, the application conditions of the different methods as exposition time, energy intensity and concentration thresholds of chemical compounds need to be specifically established and continuously improved for each matrix type to reduce to the maximum the physicochemical, nutritional and sensorial changes. In addition, the combination of the methods (hurdle concept) may be an alternative to enhance the matrix decontamination. In this way, undesirable changes in meat and fish products can be further reduced without a decrease in the efficiency of the decontamination.

Hurdle enhancement of acidic electrolyzed water antimicrobial efficacy on Bacillus cereus spores using ultrasonication

This study evaluated the inactivation effect of ultrasonic treatment combined with acidic electrolyzed water (AEW) on Bacillus cereus spores. AEW treatment reduced the spores by 1.05-1.37 log CFU/mL while the sporicidal effect of ultrasound was minor. More strikingly, simultaneous ultrasonic and AEW treatments for 30 min led to 2.29 log CFU/mL reduction and thus, considered a synergistic effect. Flow cytometry combined with SYTO/PI staining analysis revealed that ultrasound hydrolyzed the cortex while the AEW partially damaged the integrity of the inner membrane. Scanning and transmission electron microscopies were used to characterize the ultrastructural changes. The detachment of the exosporium induced by ultrasound was the most apparent difference compared with the control group, and the electron density of spores appeared to be heterogeneous after treatment with AEW. These results indicated that combining ultrasound with AEW is a promising decontamination technology with potential uses in the food industry and environmental remediation.

Bacterial control and structural and physicochemical modification of bovine Longissimus dorsi by ultrasound

A multifactorial study to evaluate the effect of three ultrasound intensities (16, 28 and 90 Wcm^-2), two sonication times (20 and 40 min), and two storage times (0 and 7 days at 4 °C) on physicochemical properties, microbiological counts, and microstructure of bovine Longissimus dorsi was performed. The results showed that ultrasound (US) did not modify luminosity (P = 0.42), redness (a*, P = 0.45), or yellowness (b*, P = 0.94). However, the hue angle increased with US treatment and during storage (P = 0.04), showing an important degradation in the color of meat treated with 16 Wcm^-2. The pH and shear force decreased during storage at 4 °C (P = 0.01). Although US did not have any significant effects on the tenderness of the meat, the interfibrillar areas increased drastically in samples treated with 16, 28 and 90 Wcm^-2 (P < 0.0001). US was effective in controlling mesophilic and psychrophilic bacteria during storage at 4 °C when intensities of 90 Wcm^-2 were used (P < 0.0001), whereas decontamination of coliform bacteria was efficient independently of ultrasonication intensity, as long as a long sonication time (40 min) was used.

Modelling inactivation of Staphylococcus spp. on sliced Brazilian dry-cured loin with thermosonication and peracetic acid combined treatment

Ultrasound (US) has a high capacity to increase food safety. Although high and/or moderate temperature in combination with US has been studied, the knowledge about cooling/low temperatures as well as its combined effect with chemical preservation methods is scarce. Therefore, the aim of this study was to describe the inactivation of Staphylococcus spp. (SA) present in the natural microbiota of sliced Brazilian dry-cured loin (Socol, BDL) using US (40 kHz and 5.40 W/g) at 1.6-17.9 kJ/g, temperature (T) between 6.4 and 73.6 °C and peracetic acid (PA) between 5.5 and 274.5 mg/L employing the Central Composite Rotatable Design. The model fully describes how the combination of US, T, and PA affects SA inactivation. In BDL, an increase in US acoustic energy density (kJ/g) allows the reduction of T necessary to inactivate SA because of the occurrence of synergistic effect. However, US applied at low T was inefficient. On the other hand, PA was more efficient at low T, since high T degraded this compound at different rates according to the holding T. Therefore, the data indicates a relation between the technologies used in the combined decontamination of sliced BDL improving dry-cured meat safety.

Ultrasound and meat quality: A review

High intensity ultrasound (HIU) offers an alternative to traditional methods of food preservation, and is regarded as a green and promising emerging technology. Ultrasound generates acoustic cavitation in a liquid medium, developing physical forces that are considered the main mechanism responsible for changes in exposed materials. In meat, ultrasound has been successfully used to improve processes such as mass transfer and marination, tenderization of meat and inactivation of microorganisms. It is also an alternative to traditional meat ageing methods for improving the quality properties of meat. Moreover, the combination of ultrasonic energy with a sanitizing agent can improve the effect of microbial reduction in foods. This review describes recent potential applications of ultrasound in meat systems, as well as physical and chemical effects of ultrasound treatment on the conservation and modification of processed meat foods. Finally, the ultrasound application parameters must be deep explored and established before the method can be scaled to industrial levels.

THE PROBLEMS OF MEAT PRODUCTS THERMAL TREATMENT

The main problems of meat products thermal treatment have been considered and analysed in the paper. Analysis of the existing research papers suggests that the main attention is devoted to the influence of temperature value and time of processing on the physical, chemical, microbiological and organoleptic indicators of the product. The influence on the protein and fat components of raw meat has been described as well as the changes in the meat product structure under the influence of temperature have been pointed out. The important impact of thermal treatment on the changes in proteins at heating, including solubility and hydration of the proteins, has been examined. The paper analyses the microbiota screening before and after thermal treatment. Special attention was paid to the impact of temperature on microbiota as it is an important indicator of a meat product safety. Methods and purpose of thermal treatments as well as the advantages and drawbacks of each method were considered. Formation of tastiness properties of the product depending on the methods and thermal cycling was emphasized. Submitted is the analysis of the factors that influence the product mass losses under the impact of high temperature. The dependence conditions of a meat product quality on the thermal cycle were also analysed. Attention is paid to alternative methods of thermal heating as well as their influence on ready product quality and safety. Substantial contribution of Odesa National Academy of Food Technologies to solving problems of the conventional thermal treatment of meat products was shown, same as a possibility of bringing a product to cooking readiness without application of high temperature. The main content of the paper includes analysis of the methods and thermal treatment cycles existing in the world and proves importance of the temperature control and cooking time which influence safety, quality and yield of the product.

Overview of Some Recent Advances in Improving Water and Energy Efficiencies in Food Processing Factories

Rapid development of food factories in both developed and developing countries, owing to continued growth in the world population, plays a critical role in the food supply chain, including environmental issues such as pollution, emissions, energy and water consumption, and thus food system sustainability. The objective of this study was to briefly review various environmental aspects of food processing operations, including aquatic, atmospheric, and solid waste generation, and also to discuss several strategies that many companies are using to reduce these negative impacts as well as to improve water and energy efficiency. To obtain higher energy efficiencies in food processing factories, two key operations can play critical roles: non-thermal processing (e.g., high pressure processing) and membrane processes. For higher water efficiency, reconditioning treatments resulting in water reuse for other purposes can be conducted through chemical and/or physical treatments. With regards to reducing volumes of processing food waste, two approaches include value-added by-product applications (e.g., animal feed) and/or utilization of food waste for energy production. Finally, we present trends for lowering operational costs in food processing.

Effect of ultrasonication and thermal and pressure treatments, individually and combined, on inactivation of Bacillus cereus spores

Bacillus cereus spores are a concern to the food industry due to their high resistance to processing and their ability to germinate to vegetative cells under suitable conditions. This research aimed to elucidate the mechanisms of Bacillus cereus spore inactivation under ultrasonication (US) combined with thermal (thermosonication, TS) treatments, with pressure (manosonication, MS) treatments, and with thermal and pressure (manothermosonication, MTS) treatments. Electronic microscopy, dipicolinic acid (DPA) release, and flow cytometric assessments were used to investigate the inactivation effect and understand the inactivation mechanisms. The sporicidal effects of the US and thermal treatment were slight, and the MS and TS also showed little inactivation effect. However, ultrasonication promoted the detachment of the exosporium, thereby reducing the spore's ability to adhere to a surface, while the thermal treatment induced a decrease in the electron density in the nucleoid of bacterium, which retained a relatively intact exosporium and coat. MS caused 92.54% DPA release, which might be due to triggering of the germinant receptors or releasing of ions and Ca²⁺-DPA. In addition, the morphological changes such as core hydration and cortex degradation were significant after treatment with MS. The release of DPA and the morphological changes were responsible for the reduction in thermal resistance. The MTS showed a remarkable inactivation effect of 3.12 log CFU/mL reductions after 30 min of treatment. It was the most effective treatment and exhibited a large fraction of damage. In addition, the MTS had a significant impact on the intracellular structure of the spores, with the coat destroyed and the cortex damaged. These results indicated that ultrasonication combined with thermal and pressure treatments had a significant sporicidal effect on Bacillus cereus spores and could be a promising green sterilization technology.

The effect of ultrasound treatment on microbial and physicochemical properties of Iranian ultrafiltered feta-type cheese

Pasteurization failures in the dairy industry have been reported in many previous studies. Hence, ultrasound, as a nonthermal alternative to pasteurization, has been studied in recent years. In this research, retentate of ultrafiltered milk was pasteurized, inoculated with Escherichia coli O157:H7, Staphylococcus aureus, Penicillium chrysogenum, or Clostridium sporogenes, and then treated with ultrasound for 20 min at frequencies of 20, 40, and 60 kHz and intensity of 80%. Microbial and physicochemical properties of the subsequently produced ultrafiltered white cheeses were investigated throughout 60 d of ripening. Sonication at 20, 40, and 60 kHz reduced counts of E. coli O157:H7, S. aureus, P. chrysogenum, and Cl. sporogenes by 4.08, 4.17, and 4.28 log; 1.10, 1.03, and 1.95 log; 1.11, 1.07, and 1.11 log; and 2.11, 2.03, and 2.17 log, respectively. Sonication improved the acidity of ripened cheese, and sonicated samples had lower pH values than control samples at the end of storage. Sonication did not affect fat in dry matter or the protein content of cheese during ripening, but it did accelerate lipolysis and proteolysis; the highest rates of lipolysis index (free fatty acid content) and proteolysis index (water-soluble nitrogen) were observed on d 60 of ripening for samples sonicated at 60 kHz. Sonication did not affect cohesiveness or springiness of cheese samples, but hardness and gumminess increased in the first 30 d and then decreased until 60 d of storage. Furthermore, ultrasound treatment improved organoleptic properties of the cheese. In terms of overall acceptance, samples sonicated at 60 kHz received the highest sensorial scores. Results showed that sonication can improve microbial, physicochemical, and sensorial properties of ultrafiltered white cheese.

Analysis of Staphylococcus aureus cell viability, sublethal injury and death induced by synergistic combination of ultrasound and mild heat

This study was designed to investigate the combined effects of ultrasound and mild heat on the viability of S. aureus in association with the cell membrane integrity and intracellular enzyme activity. Cells were treated by ultrasound under 55°C for 3, 5, 7, 10, and 15min. The dynamic changes of S. aureus cell viability, sublethal injury and death were evaluated using flow cytometric assay. Microscopies were applied to identify the morphological appearance, ultrastructure and topography of S. aureus. The results showed the membrane damage was synchronous with esterase inhibition during the exposure to sonication, leading to the immediate lethal effect. On the other hand, bacteria under the mild heat at 55°C were inactivated via a sublethal injury process. The different lethal modes were observed between sonication and mild heat treatments, which could synergistically inactivate S. aureus. The antibacterial value of thermo-sonication was greater than the sum of the individual treatments. The thermo-sonication combination synergistically reduced the number of sublethal cells and also resulted in severe cell damage.

Effects of ultrasound on microbial growth and enzyme activity

Nowadays, ultrasound is widely used in many aspects. In the last few years, many papers have concentrated on the applications of ultrasound in engineering, chemistry, medicine, physics and biology, but few in biological effects such as the acceleration effects on proliferation of microbial cells, the inactivation effects on microorganisms and the influences on the activities of enzyme. Thus, the objective of this review is to investigate the biological effects of ultrasound on these aspects.