Combining antimicrobial substances for Campylobacter post harvest mitigation on chicken breast fillet and chicken skin - any synergistic effects?

AIMS: To reduce Campylobacter along the food chain, we investigated the mitigation potential of four antimicrobial compounds against Campylobacter using a new evaluation scheme. METHODS AND RESULTS: Using the checkerboard method, the minimum inhibitory concentration (MIC) values of two organic acids (peroxyacetic acid and lactic acid) and two plant extracts (carvacrol and resveratrol) against a C. jejuni and a C. coli field isolate were determined as well as the fractional inhibitory concentration (FIC) indices of combined treatment. The lowest MIC values were found for peroxyacetic acid (0.03 mg mL-1) and carvacrol (0.06 mg mL-1). Based on subsequent sensory studies, peroxyacetic acid and carvacrol were selected for challenge tests to quantitatively determine the reducing potential against Campylobacter on chicken meat and chicken skin. Applying peroxyacetic acid significantly reduced Campylobacter counts on chicken skin with maximum reductions of 3.3 log-units (P < .0001), while the combination of peroxyacetic acid and carvacrol resulted in significant reductions of only 0.4 log-units on chicken breast fillet 24 hours after treatment but not thereafter (P = .0192). CONCLUSIONS: Peroxyacetic acid is suitable as a postharvest intervention measure to reduce Campylobacter concentration on chicken skin without reducing consumer acceptance.

Impact of preculture temperature on peracetic acid-induced inactivation and sublethal injury of L. monocytogenes and subsequent growth potential of single cells.

The disinfectant peracetic acid (PAA) that is used in the food industry can cause sublethal injury in L. monocytogenes. The effect of preculture temperature on the inactivation and sublethal injury of L. monocytogenes cells due to PAA was evaluated by plating on non-selective and selective agar medium supplemented with 5 % (w/v) NaCl. L. monocytogenes cells were precultured at 30 °C, 20 °C or 4 °C, and the former was used as reference temperature. Preculture of cells at 20 °C or 4 °C and subsequent exposure to PAA at the respective growth temperatures caused higher injury compared to cells grown at 30 °C and exposed to PAA 20 °C and PAA 4 °C, respectively. Survival was also affected by the preculture temperature; 20 °C-grown cultures resulted in lower survival at PAA 20 °C. Nevertheless, preculture at 4 °C resulted in a similar number of surviving cells when exposed to PAA 4 °C compared to cells precultured at 30 °C and exposed to PAA at 4 °C. Flow cytometry was subsequently used to quantify outgrowth capacity of stressed and sublethal damaged populations following sorting of single cells in nutrient rich medium (Tryptone soy broth supplemented with yeast extract [TSBY]). PAA treatment affected the outgrowth of L. monocytogenes at single-cell level resulting in increased outgrowth-times reflecting higher single cell heterogeneity. To conclude, the response of L. monocytogenes when exposed to PAA depended on the preculture conditions, and the highly heterogeneous outgrowth potential of PAA-injured cells may affect their detection accuracy and pose a food safety risk.

Carbon nitride nanotubes anchored with Cu(I) triggers peracetic acid activation with visible light for removal of antibiotic contaminants: Probing mechanisms of non-radical pathways and identifying active sites.

The peracetic acid (PAA)-activation process has attracted much attention in wastewater treatment. However, the low electron efficiency at the interface between heterogeneous catalysts and PAA has affected its practical application. For this study, we developed a carbon nitride hollow-nanotube catalysts with dispersed Cu(I) sites (Cu(I)-TCN) for the photocatalytic activation of PAA for antibiotics degradation. The obtained Cu(I)-TCN catalyst demonstrated an enhanced capacity for visible light harvesting along with increased charge transfer rates. Specifically, the developed Cu(I)-TCN/visible light/PAA system was able to completely remove antibiotics within 20 min, with a kinetic constant that was 25 times higher than a Cu(I)-TCN/visible light system, and 83 times higher than Cu(I)-TCN/PAA systems. Scavenging experiment and electron paramagnetic resonance (EPR) indicated that singlet oxygen was dominant reactive specie for sulfisoxazole (SIZ) removal. Besides, electrochemical tests and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy verified that the electron transfer efficiency of PAA activation was promoted due to the formation of inner-sphere interactions between PAA and Cu(I)-TCN, resulting in the quick removal of antibiotics. Further, after exposure to visible light, the Cu(I)-TCN excited photogenerated electrons which supplemented the electrons consumed in the reaction and drove the valence cycle of Cu ions. Overall, this research offered novel insights into the non-radical pathway for heterogeneous visible light-driven advanced oxidation processes and their potential for practical wastewater remediation.

Peracetic acid application as an antimicrobial and its residual (HEDP): a holistic approach on the technological characteristics of chicken meat.

The most significant occurrence of food-borne diseases is due to Campylobacter and Salmonella contamination from chicken meat, and for this reason, strict regulations about strategies to improve the control of food pathogens are imposed by food safety authorities. Despite the efforts of poultry industry since the beginning of risk analysis and critical control point to reduce the burden of food-borne illness, technological barriers along the way are increasingly necessary to ensure safe food. The aim of this review was to carry out a scientific approach to the influence of peracetic acid (PAA) as an antimicrobial and its toxicological safety, in particular the stabilizer used in the formulation of PAA, 1-hydroxyethylidene 1,1-diphosphonic acid (HEDP), suggesting the possibility of researching the residual HEDP in meat, which would allow the approval of the PAA by the health authorities of several countries that still restrict it. This review also aims to ascertain the effectiveness of PAA, in different cuts and carcasses, by different application methods, comparing the effectiveness of this antimicrobial with other antimicrobials, and its exclusive or combined use, for the decontamination of poultry carcasses and raw parts. The literature results support the popularity of PAA as an effective intervention against pathogenic bacteria during poultry processing.

Antimicrobial and antibiofilm potentiation by a triple combination of dual biocides and a phytochemical with complementary activity.

The failure of current sanitation practices requires the development of effective solutions for microbial control. Although combinations using antibiotics have been extensively studied to look for additive/synergistic effects, biocide combinations are still underexplored. This study aims to evaluate the antimicrobial effectiveness of dual biocide and triple biocide/phytochemical combinations, where phytochemicals are used as quorum sensing (QS) inhibitors. The biocides selected were benzalkonium chloride (BAC) and peracetic acid (PAA) - as commonly used biocides, and glycolic acid (GA) and glyoxal (GO) - as alternative and sustainable biocides. Curcumin (CUR) and 10-undecenoic acid (UA) were the phytochemicals selected, based on their QS inhibition properties. A checkerboard assay was used for the screening of chemical interactions based on the cell growth inhibitory effects against Bacilluscereus and Pseudomonasfluorescens. It was observed that dual biocide combinations resulted in indifference, except the PAA + GA combination, which had a potential additive effect. PAA + GA + CUR and PAA + GA + UA combinations also triggered additive effects. The antimicrobial effects of the combinations were further evaluated on the inactivation of planktonic and biofilm cells after 30 min of exposure. These experiments corroborated the checkerboard results, in which PAA + GA was the most effective combination against planktonic cells (additive/synergistic effects). The antimicrobial effects of triple combinations were species- and biocide-specific. While CUR only potentiate the antimicrobial activity of GA against B.cereus, GA + UA and PAA + GA + UA combinations promoted additional antimicrobial effects against both bacteria. Biofilms were found to be highly tolerant, with modest antimicrobial effects being observed for all the combinations tested. However, this study demonstrated that low doses of biocides can be effective in bacterial control when combining biocides with a QS inhibitor, in particular, the combination of the phytochemical UA (as a QS inhibitor) with GA and PAA.

Effects of Chemical Sterilization and Gamma Irradiation on the Biochemical and Biomechanical Properties of Human Tendon Allografts In Vitro Study.

OBJECTIVE: Pre-implantation sterilization procedures for tendons are important measures to reduce the risk of disease transmission, however these procedures may compromise tendon microarchitecture and biomechanical properties to varying degrees. We explore the effects of different sterilization procedures on the micro-histology, biomechanical strength and biochemical properties of human tendon allografts in vitro study. METHODS: The tendon allografts were harvested from cadaveric donors after the donors were serologically screened by antibody or nucleic acid testing of infectious agents. All samples were divided into five groups, which were fresh-frozen group (control group), 15 kGy gamma irradiation group, 25 kGy gamma irradiation group, 70% ethanol group, and peracetic acid-ethanol group. Each group included 10 tendons for testing. Histological staining and transmission electron microscopy were applied to observe the internal structure and arrangement of tendon collagen fibers, while the machine learning classifier was trained to distinguish the darker cross-sections of collagen fibers and brighter backgrounds of the electron micrograph to detect the distribution of diameters of tendon collagen fibers. The viscoelasticity, mechanical properties and material properties of tendon allografts were examined to detect the influence of different intervention factors on the biomechanical properties of tendons. RESULTS: Histological staining and transmission electron microscopy showed that the structure of fresh-frozen tendons was similar to the structures of other experimental groups, and no obvious fiber disorder or delamination was observed. In the uniaxial cyclic test, the cyclic creep of 25 kGy irradiation group (1.5%) and peracetic acid-ethanol group (1.5%) were significantly lower than that of the control group (3.6%, F = 1.52, P = 0.039) while in the load-to-failure test, the maximum elongation and maximum strain of the peracetic acid-ethanol group were significantly higher than those of the control group (F = 4.60, P = 0.010), and there was no significant difference in other biomechanical indicators. According to the experimental results of denatured collagen, it could be seen that no matter which disinfection procedure was used, the denaturation of the tendon sample would be promoted (F = 1.97, P = 0.186), and high-dose irradiation seemed to cause more damage to collagen fibers than the other two disinfection procedures (296.2 vs 171.1 vs 212.9 µg/g). CONCLUSION: Biomechanical experiments and collagen denaturation tests showed that 15 kGy gamma irradiation and 70% ethanol can preserve the biomechanical strength and biochemical properties of tendons to the greatest extent, and these two sterilization methods are worthy of further promotion.

Inactivation Mechanism and Efficacy of Grape Seed Extract for Human Norovirus Surrogate.

Proper disinfection of harvested food and water is critical to minimize infectious disease. Grape seed extract (GSE), a commonly used health supplement, is a mixture of plant-derived polyphenols. Polyphenols possess antimicrobial and antifungal properties, but antiviral effects are not well-known. Here we show that GSE outperformed chemical disinfectants (e.g., free chlorine and peracetic acids) in inactivating Tulane virus, a human norovirus surrogate. GSE induced virus aggregation, a process that correlated with a decrease in virus titers. This aggregation and disinfection were not reversible. Molecular docking simulations indicate that polyphenols potentially formed hydrogen bonds and strong hydrophobic interactions with specific residues in viral capsid proteins. Together, these data suggest that polyphenols physically associate with viral capsid proteins to aggregate viruses as a means to inhibit virus entry into the host cell. Plant-based polyphenols like GSE are an attractive alternative to chemical disinfectants to remove infectious viruses from water or food. IMPORTANCE Human noroviruses are major food- and waterborne pathogens, causing approximately 20% of all cases of acute gastroenteritis cases in developing and developed countries. Proper sanitation or disinfection are critical strategies to minimize human norovirus-caused disease until a reliable vaccine is created. Grape seed extract (GSE) is a mixture of plant-derived polyphenols used as a health supplement. Polyphenols are known for antimicrobial, antifungal, and antibiofilm activities, but antiviral effects are not well-known. In studies presented here, plant-derived polyphenols outperformed chemical disinfectants (i.e., free chlorine and peracetic acids) in inactivating Tulane virus, a human norovirus surrogate. Based on data from molecular assays and molecular docking simulations, the current model is that the polyphenols in GSE bind to the Tulane virus capsid, an event that triggers virion aggregation. It is thought that this aggregation prevents Tulane virus from entering host cells.

Peracetic acid activity on biofilm formed by Escherichia coli isolated from an industrial water system.

One of the major problems in industrial water systems is the generation of biofilm, which is resistant to antimicrobial agents and causes failure of sanitization policy. This work aimed to study the anti-biofilm activity of peracetic acid (PAA) at contact times and temperatures combinations. To this end, a 96-well microtiter-based calorimetric method was applied in in vitro biofilm production using Escherichia coli, isolated from the water supply system of a pharmaceutical plant. The phenotypic and phylogenetic tests confirmed that the isolated bacteria belong to strains of Escherichia coli. The anti-biofilm activity of peracetic acid on formed biofilm was investigated at concentrations of 0·15-0·5% for a contact time of 5-15 min at 20-60°C. The maximum biofilm formation by MTP method using an Escherichia coli isolate was achieved in 96-h incubation in TSB containing wells at 37°C. Biofilm formation rate shown to be high by the environmental isolate compared with that of standard strain. PAA at concentrations above 0·25%, the temperature of 40°C and a minimum of 10 min of contact time was effective in the eradication of biofilm in an MTP-based system.

Leakage of Endotoxins through the Endotoxin Retentive Filter: An in vitro Study.

INTRODUCTION: Ultrapurification of dialysis fluid has enabled highly efficient dialysis treatments. Online hemodiafiltration is one such treatment that uses a purified dialysis fluid as a supplemental fluid. In this method, an endotoxin retentive filter (ETRF) is used in the final step of dialysis fluid purification, with the aim of preventing leakage of endotoxins. Sodium hypochlorite and peracetic acid are used as disinfecting agents for the dialysis fluid pipes containing the ETRF; however, the effects of these agents on ETRF membrane pores have not been fully clarified. METHODS: Water permeability (flux) and endotoxin permeability were assessed in 3 types of ETRFs made with different membrane materials: polyester polymer alloy (PEPA), polyether sulfone (PES), and polysulfone (PS). High-concentration sodium hypochlorite and 2 types of peracetic acid were used as disinfecting agents, and the changes in flux and the endotoxin sieving coefficient (SC) were measured. RESULTS: After repeated use of high concentrations of sodium hypochlorite and peracetic acid, the PEPA and PES ETRFs did not permit passage of endotoxins, regardless of their flux. However, in the PS ETRF, the flux and endotoxin SC increased with the number of cleaning cycles. No differences were observed according to the concentration of peracetic acid disinfecting agents. CONCLUSION: PEPA and PES ETRFs completely prevent endotoxin leakage and can be disinfected at concentrations higher than the conventionally recommended concentration without affecting pore expansion. Even new PS ETRFs have low levels of endotoxin leakage, which increase after disinfection cycles using sodium hypochlorite and peracetic acid.

In Vitro Virulence Potential, Surface Attachment, and Transcriptional Response of Sublethally Injured Listeria monocytogenes following Exposure to Peracetic Acid.

The disinfectant peracetic acid (PAA) can cause high levels of sublethal injury to Listeria monocytogenes. This study aims to evaluate phenotypic and transcriptional characteristics concerning the surface attachment and virulence potential of sublethally injured L. monocytogenes ScottA and EGDe after exposure to 0.75 ppm PAA for 90 min at 4°C and subsequent incubation in tryptic soy broth supplemented with yeast extract (TSBY) at 4°C. The results showed that injured L. monocytogenes cells (99% of the total population) were able to attach (after 2 and 24 h) to stainless steel coupons at 4°C and 20°C. In vitro virulence assays using human intestinal epithelial Caco-2 cells showed that injured L. monocytogenes could invade host cells but could not proliferate intracellularly. The in vitro virulence response was strain dependent; injured ScottA was more invasive than EGDe. Assessment of PAA injury at the transcriptional level showed the upregulation of genes (motB and flaA) involved in flagellum motility and surface attachment. The transcriptional responses of L. monocytogenes EGDe and ScottA were different: only injured ScottA demonstrated upregulation of the virulence genes inlA and plcA. Downregulation of the stress-related genes fri and kat and upregulation of lmo0669 were observed in injured ScottA. The obtained results indicate that sublethally injured L. monocytogenes cells may retain part of their virulence properties as well as their ability to adhere to food-processing surfaces. Transmission to food products and the introduction of these cells into the food chain are therefore plausible scenarios that are worth taking into consideration in terms of risk assessment. IMPORTANCE L. monocytogenes is the causative agent of listeriosis, a serious foodborne illness. Antimicrobial practices such as disinfectants used for the elimination of this pathogen in the food industry can produce a sublethally injured population fraction. Injured cells of this pathogen that may survive antimicrobial treatment may pose a food safety risk. Nevertheless, knowledge regarding how sublethal injury may impact important cellular traits and phenotypic responses of this pathogen is limited. This work suggests that sublethally injured L. monocytogenes cells maintain virulence and surface attachment potential and highlights the importance of the occurrence of sublethally injured cells regarding food safety.

Listeria monocytogenes Sublethal Injury and Viable-but-Nonculturable State Induced by Acidic Conditions and Disinfectants.

The dormancy continuum hypothesis states that in response to stress, cells enter different stages of dormancy ranging from unstressed living cells to cell death, in order to ensure their long-term survival under adverse conditions. Exposure of Listeria monocytogenes cells to sublethal stressors related to food processing may induce sublethal injury and the viable-but-nonculturable (VBNC) state. In this study, exposure to acetic acid (AA), hydrochloric acid (HCl), and two disinfectants, peracetic acid (PAA) and sodium hypochlorite (SH), at 20°C and 4°C was used to evaluate the potential induction of L. monocytogenes strain Scott A into different stages of dormancy. To differentiate the noninjured subpopulation from the total population, tryptic soy agar with 0.6% yeast extract (TSAYE), supplemented or not with 5% NaCl, was used. Sublethally injured and VBNC cells were detected by comparing plate counts obtained with fluorescence microscopy and by using combinations of carboxyfluorescein and propidium iodide (viable/dead cells). Induction of sublethal injury was more intense after PAA treatment. Two subpopulations were detected, with phenotypes of untreated cells and small colony variants (SCVs). SCVs appeared as smaller colonies of various sizes and were first observed after 5 min of exposure to 5 ppm PAA at 20°C. Increasing the stress intensity from 5 to 40 ppm PAA led to earlier detection of SCVs. L. monocytogenes remained culturable after exposure to 20 and 30 ppm PAA for 3 h. At 40 ppm, after 3 h of exposure, the whole population was considered nonculturable, while cells remained metabolically active. These results corroborate the induction of the VBNC state. IMPORTANCE Sublethally injured and VBNC cells may evade detection, resulting in underestimation of a food product's microbial load. Under favorable conditions, cells may regain their growth capacity and acquire new resistant characteristics, posing a major threat for public health. Induction of the VBNC state is crucial for foodborne pathogens, such as L. monocytogenes, the detection of which relies almost exclusively on the use of culture recovery techniques. In the present study, we confirmed that sublethal injury is an initial stage of dormancy in L. monocytogenes that is followed by the VBNC state. Our results showed that PAA induced SCVs (a phenomenon potentially triggered by external factors) and the VBNC state in L. monocytogenes, indicating that tests of lethality based only on culturability may provide false-positive results regarding the effectiveness of an inactivation treatment.

Lactic Acid and Peroxyacetic Acid Inhibit Biofilm of Escherichia coli O157:H7 Formed in Beef Extract.

The objective of this study was to evaluate the inhibitory effect of lactic acid (LA) and peroxyacetic acid (PAA) on the biofilm formation of Escherichia coli O157:H7 in beef extract (BE). BE medium was used as the growth substrate in this study, to make the control effect closer to the situation of the factory. The biofilm inhibitory efficacy of LA and PAA was tested by using a crystal violet staining assay and microscopic examination. And then, extracellular polymeric substance (EPS) production, metabolic activity, and real-time polymerase chain reaction assay were used to reveal the biofilm inhibition mechanism of LA and PAA. The results showed that both LA and PAA significantly inhibited biofilm formation of E. coli O157:H7 at minimum inhibitory concentrations (MICs) (p < 0.05). At MIC, LA and PAA showed different effects on the biofilm metabolic activity and the EPS production of E. coli O157:H7. Supporting these findings, expression analysis showed that LA significantly suppressed quorum sensing genes (luxS and sdiA) and adhesion genes (flhC), while PAA downregulated the transcription of extracellular polysaccharide synthesis genes (adrB and adrA) and the global regulatory factor csgD. This result revealed that LA and PAA had different biofilm inhibitory mechanisms on E. coli O157:H7; LA inhibited the biofilm formation mainly by inhibiting metabolic activity, while PAA inhibited EPS production. This study provided a theoretical basis for the control of E. coli O157:H7 biofilm in the actual production process.

On-site generated peroxy acetic acid (PAA) technology reduces Salmonella and Campylobacter on chicken wings.

Peroxyacetic acid (PAA) is a widely used antimicrobial during poultry processing that requires to be shipped in a concentrated solution, stored under hazardous conditions and diluted for use. On-site PAA generation using nonhazardous ingredients can help eliminate transportation and storage issues at the processing plant and reduce the risk of occupational hazards. The objective of the proposed research was to 1) evaluate the efficacy of on-site generated PAA in reducing Salmonella and Campylobacter populations compared to the commercially available PAA stock solutions and 2) to perform color measurements to evaluate any deviations between treatments. PAA solutions at 50 and 100 ppm were used for treating the chicken wings. Fresh chicken wings (0.45 kg) were inoculated with a cocktail of nalidixic acid resistant Salmonella Typhimurium (STNR) and gentamicin resistant Campylobacter coli (CCGR) and immersed in PAA solutions (50 and 100 ppm) adjusted to pH 8.5 and 10.0 or 10.5, for either 10 s or 60 min. Treated chicken wings were rinsed for 1 min in chilled BPW (100 mL), serially diluted and plated on APC Petrifilm for Salmonella, spread plated on Campy-cefex agar supplemented with gentamicin (200 ppm) for Campylobacter enumeration. Immersion of chicken wings in 100 ppm PAA for 60 min irrespective of pH levels and PAA solutions resulted in greater microbial reductions (P < 0.05) of Salmonella by 1.68 and 1.42 log CFU/mL for SaniDate, 1.82 and 1.83 log CFU/mL for OxyFusion (on-site generated). For the same treatments, Campylobacter reductions of 1.59 and 1.36 log CFU/mL for SaniDate, 1.63 and 1.71 log CFU/mL for OxyFusion were achieved. The antimicrobial efficiency of PAA was not affected by pH and type of PAA solution. No significant differences (P > 0.05) in color were observed between treatments and controls. On-site generated PAA provides poultry processors an effective, safer, and less hazardous alternative to commercially available PAA solutions, ensuring poultry workers' health and safety.

The efficiency of antineoplastic drug contamination removal by widely used disinfectants-laboratory and hospital studies.

OBJECTIVE: Antineoplastic drugs (ADs) pose risks to healthcare staff. Surface disinfectants are used in hospitals to prevent microbial contamination but the efficiency of disinfectants to degrade ADs is not known. We studied nine disinfectants on ten ADs in the standardized laboratory and realistic in situ hospital conditions. METHODS: A survey in 43 hospitals prioritized nine most commonly used disinfections based on different ingredients. These were tested on inert stainless steel and in situ on contaminated hospital flooring. The effects against ten ADs were studied by LC-MS/MS (Cyclophosphamide CP; Ifosfamide IF; Capecitabine CAP; Sunitinib SUN; Methotrexate MET; Doxorubicin DOX; Irinotecan IRI; Paclitaxel PX; 5-Fluorouracil FU) and ICP-MS (Pt as a marker of platinum-based ADs). RESULTS: Monitoring of the floor contamination in 26 hospitals showed that the most contaminated are the outpatient clinics that suffer from a large turnover of staff and patients and have limited preventive measures. The most frequent ADs were Pt, PX, FU and CP with maxima exceeding the recommended 1 ng/cm2 limit by up to 140 times. IRI, FU, MET, DOX and SUN were efficiently removed by hydrolysis in clean water and present thus lower occupational risk. Disinfectants based on hydrogen peroxide were efficient against PX and FU (> 70% degradation) but less against other ADs, such as carcinogenic CP or IF, IRI and CAP. The most efficient were the active chlorine and peracetic acid-based products, which however release irritating toxic vapors. The innovative in situ testing of ADs previously accumulated in hospital flooring showed highly problematic removal of carcinogenic CP and showed that alcohol-based disinfectants may mobilize persistent ADs contamination from deeper floor layers. CONCLUSION: Agents based on hydrogen peroxide, peracetic acid, quaternary ammonium salts, glutaraldehyde, glucoprotamine or detergents can be recommended for daily use for both disinfection and AD decontamination. However, they have variable efficiencies and should be supplemented by periodic use of strong chlorine-based disinfectants efficient also against the carcinogenic and persistent CP.

Valorization of orange bagasse through one-step physical and chemical combined processes to obtain a cellulose-rich material.

BACKGROUND: Orange bagasse (OB) is an agroindustrial residue of great economic importance that has been little explored for the extraction of cellulose. The present study aimed to investigate different combinations of chemical (sodium hydroxide, peracetic acid and alkaline peroxide) and physical (autoclaving and ultrasonication) treatments performed in one-step processes for cellulose extraction from OB and to characterize the materials obtained according to their composition, morphology, crystallinity and thermal stability. RESULTS: The processing yields ranged from 140 to 820 g kg-1 , with a recovery of 720-1000 g kg-1 of the original cellulose. Treatments promoted morphological changes in the fiber structure, resulting in materials with higher porosity, indicating partial removal of the noncellulosic fractions. The use of combined chemical treatments (NaOH and peracetic acid) with autoclaving was more efficient for obtaining samples with the highest cellulose contents. CONCLUSION: Therefore, ACSH (processed by autoclaving with NaOH) was the most effective one-step treatment, resulting in 71.1% cellulose, 0% hemicellulose and 19.0% lignin, with a crystallinity index of 42%. The one-step treatments were able to obtain materials with higher cellulose contents and yields, reducing reaction times and the quantity of chemical reagents employed in the overall processes compared to multistep conventional processes. © 2020 Society of Chemical Industry.

Water UV-C treatment alone or in combination with peracetic acid: A technology to maintain safety and quality of strawberries.

Disinfection of fruits is one of the most important steps since they are going to be eaten fresh-or minimally-processed. This step affects quality, safety, and shelf-life of the product. Despite being a common sanitizer in the fruit industry, chlorine may react with organic matter leading to the formation of toxic by-products. Alternative sustainable disinfection strategies to chlorine are under study to minimize environmental and human health impact. Water-assisted UV-C light (WUV-C) is proposed here as an alternative sanitizing method for strawberries. In this study, strawberries were washed for 1 or 5 min in a tank with 2 or 4 lamps on, each emitting UV-C light at 17.2 W/cm2, or in a chlorine solution (200 ppm, pH 6.5). Moreover, trials with 4 lamps on, together with a washing solution consisting on peracetic acid at 40 or 80 ppm, were carried out. Overall, quality and nutritional parameters of strawberries after treatments were maintained. Changes in color were not noticeable and fruits did not lose firmness. No major changes were observed in antioxidant activity, organic acid, anthocyanin, vitamin C, and total phenolic content. Yeasts and molds were not affected by the WUV-C treatment, and 5 min were needed to significantly reduce total aerobic mesophylls population. However, reductions of artificially inoculated Listeria innocua and Salmonella Typhimurium after WUV-C treatments were comparable to those obtained with chlorine-wash, which were 3.0 log CFU / g. Moreover, WUV-C light was effective to minimize microorganisms remaining in washing water, avoiding cross-contamination and thus, allowing water recirculation. This effect was improved when combining the action of UV-C light with peracetic acid, showing the suitability of this combined treatment, understood as an alternative to chlorine sanitation, for sanitizing strawberries and keeping the populations of pathogenic bacteria in washing water lower than 0.6 ±â€¯0.1 log CFU / mL.

Verification of peroxyacetic acid treatment against L. monocytogenes on fresh apples using E. faecium NRRL B-2354 as a surrogate in commercial spray-bar operations.

Peroxyacetic acid (PAA) is a commonly used antimicrobial in apple spray bar interventions during post-harvest packing. However, limited information is available about its efficacy against foodborne pathogens on fresh apples under commercial packing conditions. In this study, the practical efficacies of PAA against Listeria monocytogenes on fresh apples during spray bar operation at ambient and elevated temperature were validated in three commercial packing facilities using Enterococcus faecium NRRL B-2354 as a surrogate strain. Apples were inoculated with E. faecium at ~6.5 Log10 CFU/apple and subjected to PAA spray bar interventions per commercial packing line practice. At each temperature and contact time intervention combination, 20-24 inoculated apples were processed together with 72-80 non-inoculated apples. Applying 80 ppm PAA at ambient temperature (17-21 °C) achieved a similar log reduction (P > 0.05) of E. faecium on Granny Smith apples (GSA) in three apple packing facilities, which caused 1.12-1.23 and 1.18-1.32 Log10 CFU/apple reductions of E. faecium on GSA for 30-sec and 60-sec intervention, respectively. Increasing the temperature of the PAA solution to 43-45 °C enhanced its bactericidal effect against E. faecium, causing 1.45, 1.86 and 2.19 Log10 CFU/apple reductions in three packing facilities for a 30-sec contact, and 1.50, 2.24, and 2.29 Log10 CFU/apple reductions for a 60-sec contact, respectively. Similar efficacies (P > 0.05) of PAA at both ambient and elevated temperature were also observed on Fuji apples. Spraying PAA on apples at ambient or elevated temperature reduced the level of E. faecium cross-contamination from inoculated apples to non-inoculated apples but could not eliminate cross-contamination. Data from this study provides valuable technical information and a reference point for the apple industry in controlling L. monocytogenes and verifying the effectiveness of their practices.

Peracetic acid reduces Campylobacter spp. on turkey skin: Effects of a spray treatment on microbial load, sensory and meat quality during storage.

Handling and consumption of Campylobacter-contaminated poultry meat is the most common cause of human campylobacteriosis. While many studies deal with interventions to reduce Campylobacter spp. on chicken carcasses, studies on other poultry species are rare. In the present study, a spray treatment with peracetic acid (PAA) on turkey carcasses was evaluated. For this, parts of breast fillets with skin and Campylobacter (C.) jejuni DSM 4688 (108 cfu/ml) inoculated drumsticks were sprayed for 30 s with PAA (1200 ppm) or water as control solution. Samples were packaged under modified atmosphere and stored at 4°C until analysis on day 1, 6 and 12. The breast fillets were used for determination of the total viable count, sensory and meat quality examination as well as myoglobin content and biogenic amines. The drumsticks were used for C. jejuni counts. PAA had a significant effect in reducing total viable counts on all days by up to 1.2 log10 compared to the untreated control. Treatment with water alone showed no effect. C. jejuni counts were significantly reduced by PAA (0.9-1.3 log10), while water achieved a 0.5 log10 reduction on C. jejuni counts on day 1. No differences in sensory, pH, electrical conductivity and myoglobin content could be found. The skin of the PAA treated fillets had lower redness values than the water control on day 1, whereas on day 12 parts of the water treated muscles were lighter than the untreated control. A lower putrescine content of the water sprayed fillets in comparison to the control sample on day 12 was the only significant difference concerning the biogenic amines. Results from this study indicate that a spray treatment with 1200 ppm PAA would be a useful measure to lower the Campylobacter spp. counts on turkey carcasses without having a negative influence on product quality.

Peracetic acid reduces Campylobacter spp. numbers and total viable counts on broiler breast muscle and drumstick skins during modified atmosphere package storage.

Constant high case numbers of human campylobacteriosis over the last few years show the necessity of efficient strategies to reduce the number of diseases. The aim of this study was to assess the effectiveness of peracetic acid (PAA) as spray application to reduce Campylobacter spp. on chicken meat. For this, the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of 25 Campylobacter jejuni and C. coli isolates were determined. All tested isolates had MICs ranging between 2 to 8 ppm PAA, while MBCs were 1- to 4-fold higher than the MIC. An additional time-kill test, using strain C. jejuni DSM 4688, revealed that after an incubation time of 2 h in medium, supplemented with 1-fold the MIC (4 ppm) of PAA, no surviving C. jejuni cells were detectable. For evaluation of a spraying treatment, C. jejuni DSM 4688 (108 cfu/mL) inoculated chicken drumsticks and native skin-on breast fillets were treated for 30 s with PAA of 1,200 ppm concentration. Samples were packaged in modified atmosphere packages and stored at 4°C until further analysis. On day 1, 6, and 12, the fillets were used for microbial (total viable count), sensory, and physicochemical (color, pH, electrical conductivity) analysis and meat samples for myoglobin redox forms and antioxidant activity were taken. A significant reduction of the total viable counts was seen on day 6 and 12 in comparison to the water control and to the untreated fillets, respectively. Campylobacter jejuni counts on the drumsticks were significantly reduced by PAA application on day 6 and 12 in comparison to the water treatment. Except on day 12, where PAA-treated fillets showed a slightly higher percentage of oxymyoglobin, no significant differences could be found in the sensory and physicochemical measurements as well as in myoglobin and antioxidant activity. Spray application of 1,200 ppm PAA to Campylobacter-contaminated chicken samples led to a significant reduction up to 1.1 log10 of Campylobacter spp. counts without influencing chemical and sensory meat quality parameters.

Anti-biofilm efficacy of single and binary treatments based on plant essential oils against Escherichia coli persistent in food-processing facilities.

The efficacy of single and combined treatments based on plant essential oils was investigated against Escherichia coli strains persistent in food-processing facilities. Surface materials (stainless steel and polystyrene), disinfectants (peracetic acid and sodium hypochlorite), and conditions (25 ℃, frequency of sanitizing of 24 h) commonly present in the food industry were also used to reach a more realistic approach. Thyme and pepper-rosmarin oils were significantly (P < 0.05) very effective against planktonic cells and biofilms formed by strains E6 and E7, respectively, followed by peracetic acid. Meanwhile, craveiro oil showed an efficacy that is significantly (P < 0.05) higher than sodium hypochlorite. All these disinfectants except sodium hypochlorite were able to kill 99.99% of biofilm cells in the range of concentrations tested (0.1%-3% v/v). However, binary treatments were needed to decrease the doses of these essential oils significantly (P < 0.05) for the control of E. coli biofilms. The effectiveness of peracetic acid against E. coli biofilms was also improved by blending with these essential oils. In particular, blends of pepper-rosmarin with thyme or peracetic acid demonstrated a suitable effectiveness for the control of persistent E. coli present in food-related environments. The application of these treatments could also reduce the current environmental impact generated during food-processing sanitization.