Microplastic Release from Single-Use Plastic Beverage Cups.

Microplastics (MPs) have attracted considerable attention as one of the most remarkable food and drink pollutants in recent years. Disposable cups, which are widely used as single-use containers, have been suspected as the primary sources of MPs found in cold and hot beverages. In this study, the effect of different exposure times (0, 5, 10 and 20 min) and temperatures (4 °C, 50 °C and 80 °C) on MP release from the single-use cups made of four different materials [polypropylene (PP), polystyrene (PS), polyethylene (PE) coated paper cups and expanded polystyrene (EPS)] into the water was investigated. The number of MPs ranged from 126 p/L to 1420 p/L, while the highest and lowest counts were observed in the PP (50 °C for 20 min) and PE-coated paper cups (4 °C 0 min), respectively. Washing the cups with ultrapure water prior to use reduced the MP release by 52-65%. SEM images demonstrated the abrasion on the surface of the disposable cups as a result of hot water exposure. Intensities of FTIR absorbance levels at some wavelengths were decreased by the water treatment, which could be evidence of surface abrasion. The annual MP exposure of consumers was calculated as 18,720-73,840 by the consumption of hot and cold beverages in disposable cups. In conclusion, as the level and potential toxicity of MP exposure in humans are not yet fully known, this study sheds light on the number of MPs transferred to cold and hot beverages from single-use disposable cups.

Polyvinyl alcohol nanoparticles loaded with propolis extract: Fabrication, characterization and antimicrobial activity.

Background and Purpose: Propolis has high potential beneficial bioactive properties such as anti-oxidative, antimicrobial, and anti-tumour activities. However, the bitter taste and the insolubility nature of propolis in water lead to some limitations in their usage in functional food applications. Experimental Approach: Herein, we evaluated the effects of nanoencapsulation of propolis at the different concentration levels (0, 0.4, 0.8, 1.0, and 1.2 %) into the polyvinyl alcohol (PVA) nanoparticles using the electrospraying method, on the structural, physical, antioxidant, antimicrobial and thermal properties. Key Results: The results revealed that the fabricated nanocapsules (PVA-NPs) obtained under optimal conditions had uniform size distribution and unstable particles with small particle size between 104-258 nm, a polydispersity index <0.317, and a zeta potential between -5 and +5 mV. The maximum encapsulation efficiency of PVA-NPs was about 25.32 % for 1 % of the initial propolis loading level. DSC thermal experiments showed an increase in the thermal stability of the propolis loaded PVA nanoparticles as compared to the neat PVA nanoparticles. The percent inhibition of DPPH radical scavenging activity of the nanocapsules was between 80 and 89 %. SEM analysis revealed that PVA-NPs had a spherical shape with a rough surface and were composed of long and thin fibres at nanometric diameters. FT-IR analysis showed that no indications of any chemical reactions were found between the constituents of the core and wall material due to their physical mixing. Antibacterial efficacy was evaluated by the Broth dilution method and PVA-NPs exhibited good inhibitory activity against S. aureus at low concentration ratios, whereas it had no inhibitory activity against E. coli O157:H7. Conclusion: PVA-NPs fabricated using the electrospraying technique can be used for the development of a new promising natural and bioactive agent in the food and pharmaceutical industry.

Use of cellulose microfibers from olive pomace to reinforce green composites for sustainable packaging applications.

To valorize abundant, unexploited, and low-cost agro-industrial by-products, olive pomace is proposed as a sustainable and renewable raw material for cellulose microfibers (CMFs) production. In this study, CMFs were extracted from olive pomace using alkaline and bleaching treatments and characterized in terms of morphological, structural, and thermal properties. Afterward, the reinforcing capability of microfibers was examined using carboxymethyl cellulose (CMC) as a polymer matrix by the solvent casting process. The effects of CMF loading (1%, 3%, 5%, and 10%) on the composites' mechanical, physical, morphological, and thermal properties were assessed. CMF incorporation led to a decrease in moisture content (MC), water solubility (WS), and water vapor permeability (WVP) and an increase in tensile strength (TS), stiffness and transparency values, and thermal stability of CMC films. Increasing CMF content to 5%, increased the TS and elasticity modulus by 54% and 79%, respectively, and reduced the WVP and light transmissivity at 280 nm, by 22% and 47%, respectively. The highest water, moisture, light barrier, and mechanical properties of composites were reached at 5% CMFs.

Development and characterization of a novel sodium alginate based active film supplemented with Lactiplantibacillus plantarum postbiotic.

In this study, sodium alginate based biodegradable films were prepared by the supplementation with postbiotics of Lactiplantibacillus plantarum subsp. plantarum (L. plantarum) W2 strain and the effect of probiotics (probiotic-SA film) and postbiotics (postbiotic-SA film) incorporation on physical, mechanical (tensile strength and elongation at break), barrier (oxygen and water vapor permeability), thermal and antimicrobial properties of the films was investigated. The pH, titratable acidity and brix of the postbiotic was 4.02, 1.24 % and 8.37, respectively while gallic acid, protocatechuic acid, myricetin and catechin were the major phenolic compounds. Mechanical and barrier properties of the alginate-based films were improved by probiotic or postbiotic supplementation while postbiotic showed a more pronounced (P < 0.05) effect. Thermal analysis showed that postbiotics supplementation increased thermal stability of the films. In FTIR spectra, the absorption peaks at 2341 and 2317 cm-1 for probiotic-SA and postbiotic-SA edible films confirmed the incorporation of probiotics/postbiotics of L. plantarum W2 strain. Postbiotic supplemented films showed strong antibacterial activity against gram-positive (L. monocytogenes, S. aureus and B. cereus) and gram-negative bacterial (E. coli O157:H7) strains while probiotic-SA films did not show any antibacterial effect against the test pathogens. SEM images revealed that the supplementation of postbiotics provided a rougher and rigid film surface. Overall, this paper brought a new perspective for development of novel active biodegradable films by incorporation of postbiotics with improved performance.

Structural Characterization, Technofunctional and Rheological Properties of Sesame Proteins Treated by High-Intensity Ultrasound.

Plant-derived proteins, such as those from sesame seeds, have the potential to be used as versatile food ingredients. End-use functionality can be further improved by high-intensity ultrasound treatments. The effects of high-intensity ultrasound on the properties of sesame protein isolates from cold-pressed sesame cake were evaluated. The SDS-PAGE demonstrated no significant changes in the molecular weight of proteins. Ultrasound treatments resulted in decreased particle size with a more uniform distribution, resulting in the exposure of hydrophobicity and free -SH groups and increased zeta potential. Although FTIR spectra of proteins were similar after ultrasonication, a partial increase in the intensity of the amide A band was observed. The ultrasound significantly (p < 0.05) affected the secondary structure of proteins. While optical micrographics revealed a dispersed structure with smaller particles after treatments, microstructural observations indicated more rough and irregular surfaces. Water solubility was improved to 80.73% in the sample subjected to 6 min of ultrasonication. Sesame protein solutions treated for 4 and 6 min exhibited viscoelastic structure (storage modulus (G') > loss modulus (G'')). In addition, the gelation temperature of proteins decreased to about 60-65 °C with increasing treatment time. Overall, ultrasound is a useful technique for the modification of sesame protein isolates.

Extraction Optimization and Characterization of Cellulose Nanocrystals from Apricot Pomace.

Apricot pomace (AP) is lignocellulosic agro-industrial waste that could be considered a good source for cellulose-based, value-added compounds. In this study, conditions for cellulose nanocrystals' (CNCs) extraction from apricot pomace (AP) were optimized using Response Surface Methodology (RSM) based on the extraction yield, and the resulting CNC was characterized using Fourier transform infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Transmittance Electron Microscopy (TEM), Thermogravimetric Analysis (TGA), and X-Ray Diffraction (XRD). The maximum CNC yield (34.56%) was obtained at a sulfuric acid concentration of 9.5 M within 60 min. FTIR analysis showed that noncellulosic components were gradually removed from the pomace. A morphological analysis of the nanocrystal was performed using SEM and TEM. CNCs were in the range of 5-100 µm in diameter and appeared as individual fibers. TGA analysis of the CNC sample revealed good thermal stability around 320°C. The crystalline index (%CI) of the CNC obtained from AP was determined to be 67.2%. In conclusion, this study demonstrated that AP could be considered a sustainable source for value-added compounds such as CNCs to contribute to a circular economy.

Production of tomato powder from tomato puree with foam-mat drying using green pea aquafaba: drying parameters and bioaccessibility of bioactive compounds.

BACKGROUND: The purpose of this study was to valorize green pea cooking water (aquafaba) as a foaming agent in foam-mat drying of tomato. For this aim, density of foam-mats (green pea aquafaba+tomato puree) changed between 1.06 and 0.45 g/mL depending on the aquafaba concentration. Foam-mats with 5 mm thickness were dried at 50, 60 and 70°C at 1.3 m/s air velocity. RESULTS: The results showed that the porous structure of foams with lower densities resulted in higher drying rates and moisture diffusivities. Redness (a* ) value decreased with increasing aquafaba content (p < 0.05). Total phenolic content (TPC) and antioxidant activity (CUPRAC, DPPH and FRAP) of the resulting tomato powders were also determined. Moreover, bioaccessibility of phenolics and antioxidant activities were also determined using in vitro digestion. CONCLUSIONS: All of the bioactive parameters are positively affected by foam-mat drying process. Using aquafaba as a foaming agent accelerated the drying period and improved bioactive characteristics of the powders. © 2022 Society of Chemical Industry.

Home-made cheese preservation using sodium alginate based on edible film incorporating essential oils.

The objective of the present study is developing a new technique for the preservation of natural cheese by the use of an edible biofilm based on sodium alginate in order to evaluate the effect of the essential oils (O. basilicum L, R. officinalis L. A. herba alba Asso. M. pulegium L.) incorporated in the film on the oxidation stability, microbial spoilage, physicochemical characteristics and sensory criteria. The cheese samples coated with sodium alginate incorporated by the oils showed moderate stability in terms of oxidative stabilities of proteins and lipids during storage. In addition, poor microbial growth (total aerobic mesophilic flora, yeasts and fecal coliforms) was observed in cheese samples coated with biofilm, also, the growth of Staphylococci Salmonella and Molds for all types of cheese were completely inhibited. Additionally, it was observed that the biofilm coating reduced the weight loss and hardness of the cheese comparing with the uncoated sample. The results of sensory analysis revealed that uncoated cheese, coated with sodium alginate and sodium alginate composed of oil of O. basilicum were the most preferred by panelists, in comparison with others. Therefore, it was concluded that this technique of coating cheese with edible film activated with essential oils is preferred and favorable by virtue of the effect of oils preserving the cheese without seriously affecting their organoleptic properties.

Role of non-thermal treatments and fermentation with probiotic Lactobacillus plantarum on in vitro bioaccessibility of bioactives from vegetable juice.

BACKGROUND: Lactic acid fermentation is a natural way to increase the bioactive and functional properties of fruit and vegetable juices. In this study, the in vitro gastrointestional digestion of phenolics, flavonoids, anthocyanins, and antioxidant activity of mixed vegetable juice was investigated as affected by fermentation with probiotic Lactobacillus plantarum and non-thermal treatments (ultraviolet (UV) and/or ultrasonic (US) treatment). For this purpose heat, US, UV or US/UV treated vegetable juice samples were fermented by probiotic L. plantarum and percentage recovery of bioactive (total phenolic (TPC), total flavonoid (TFC) and total anthocyanin contents (TAC) and antioxidant (DPPH [1,1-diphenyl-2-picrylhydrazyl] and CUPRAC [CUPric Reducing Antioxidant Capacity]) properties was evaluated during simulated gastrointestinal digestion. RESULTS: Total mesophilic aerobic bacteria (TMAB) and total yeast-mold (TYM) counts were significantly decreased by thermal and non-thermal processes and coliforms were fully eliminated. The bioaccessibility of total phenolics, anthocyanins, and flavonoids decreased after in vitro digestion. In general, recovery (5.78-34.71%) and serum availability of the bioactives was positively influenced by the fermentation and non-thermal treatments. Phenolics and anthocyanins exhibited the highest and the lowest recovery, respectively, while post-digestion recovery of antioxidant was between that of the phenolics and anthocyanins. CONCLUSIONS: This study confirmed that US and UV treatment could be advantageous alternatives to heat treatment for ensuring the microbial safety of vegetable juices with increased in vitro bioaccessibility of bioactive compounds while probiotic fermentation with L. plantarum contributed to the improvement of the bioactive profile. © 2021 Society of Chemical Industry.

Extraction of a novel water-soluble gum from nettle (Urtica dioica) seeds: Optimization and characterization.

Nettle seed gum (NSG) which is a novel potential source of hydrocolloid was characterized in terms of yield, physicochemical, rheological, functional and thermal properties. According to Response Surface Methodology, the maximum extraction yield was determined as 6.17% on dry basis. In order to clarify the structural information of the gum, the FT-IR analysis and monosaccharide composition determination were performed. In the results, the NSG had 8.48% moisture, 10.81% total ash, 2.89% total protein, 1.15% total oil and 76.67% total carbohydrate. The FT-IR analysis revealed the existence of carboxyl groups, which gives the gum the capability of ion binding. Furthermore, Mannose/Galactose ratio was calculated as 1.07, indicating the water solubility of gum. DSC analysis showed that the NSG was highly stable in thermal process. Intrinsic viscosity, average viscosity and molecular weight values were determined as 8.56 ± 0.4 dL/g and 1.89 ± 0.1 × 106 g/mol, respectively. The emulsification capacity, emulsion stability and foam formation capacity of the NSG were 48%, 40% and 4%, respectively. The NSG exhibited shear thinning behavior while dynamic rheological analysis indicated the NSG had viscoelastic properties and G' (the storage modulus) was higher than G″ (the loss modulus). In conclusion, the present study supplied novel knowledge on the NSG, which will be inestimable for clarifying its matchless functional properties.

Optimization of production parameters for fabrication of thymol-loaded chitosan nanoparticles.

Thymol is the major antimicrobial and bioactive constituent found in thyme (Thymus vulgaris) essential oil. In this study, it was aimed to determine the parameters for fabrication of thymol loaded chitosan nanoparticles with optimum encapsulation efficiency, zeta potential, and particle size properties using a two-stage emulsion-ionic gelation approach. For this purpose, temperature (25-45 °C) and chitosan (3-6 mg/mL), thymol (3-6 mg/mL), Tween 80 (3-6 mg/mL) and TPP (0.15-0.75 mg/mL) concentrations were studied as optimization parameters by applying the numerical point prediction method. The results showed that the particle size, zeta potential and encapsulation efficiency of the chitosan nanoparticles could be controlled by processing conditions. Additionally, this study was focused on optimization of these parameters with factorial design (FD) in nanoencapsulation of Thymol. The optimized production parameters on the basis of the criteria of attaining the minimum particle size, maximum zeta potential, and maximum encapsulation efficiency were 42 °C temperature, chitosan rate 3 mg/mL, Thymol rate 5.9 mg/mL, Tween 80 rate 3 mg/mL and TPP rate 0.75 mg/mL.

Development and characterization of sodium alginate based active edible films incorporated with essential oils of some medicinal plants.

The aim of this study was to develop sodium alginate based active films incorporated with essential oils (EO) of R. officinalis L, A. herba alba Asso, O. basilicum L and M. pulegium L. the films were characterized in terms of bioactive properties including thickness, moisture content, water vapor and oxygen permeability, release test, mechanical, molecular, biodegradability and thermal properties. The results showed that the active films had a strong antibacterial effect against the six pathogenic bacteria with the inhibition zone between18.5 and 38.67 mm. furthermore, the antioxidant capacity of the films ranged from 4.57% to 23.09%. According to results of release test, physical, molecular, mechanical, biodegradability, thermal and barrier properties, the EOs were uniformly dispersed in the polymer matrix and improved slightly thermal (Tm) and barrier properties, while decreased tensile strength and it was obtained that this film is biodegradable in the soil. In conclusion, it could be said that sodium alginate based edible films incorporated with EO have a potential to be used food packaging applications.

Development of LLDPE based active nanocomposite films with nanoclays impregnated with volatile compounds.

In this study, a novel procedure was performed for grafting of nanoclays (montmorillonite (MMT) and halloysite (HNT)) with essential oil constituents (thymol (THY), eugenol (EUG) and carvacrol (CRV)) using Tween 80 as surfactant and then the nanoclay particles were incorporated into LLDPE pellets (5 wt%) to produce active nanocomposite films using a twin screw extruder. The resulting nanocomposite films were analyzed for antimicrobial and antioxidant capacity as well as thickness, mechanical, color, barrier, thermal properties and surface morphology and molecular composition. Release of the active compounds from the films at the refrigerated and room temperature conditions were also tested. The results showed that the films had strong in vitro antibacterial activity against pathogenic bacteria (Salmonella Typhimurium, Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus) while their effect against lactic acid bacteria (Lactobacillus rhamnosus and Lb. casei) was limited. The lowest and highest DPPH scavenging ability levels were 65.59% and % 87.92, belonged to THY-MMT and EUG-MMT, respectively. Release of active compounds at 24 °C was much more rapid than at 4 °C. CRV-HNT and THY-HNT provided slower release than the other films. SEM results showed that nanoclays were uniformly dispersed in the polymer matrix with exceptional agglomerates. Incorporation of the active nanoclays significantly (P > 0.05) improved tensile strength and elongation of the films. The results confirmed that LLDPE based active nanocomposite films could be successfully produced due to its good interaction with MMT and HNT, activated with THY, EUG and CRV.

Production and characterization of a new biodegradable fenugreek seed gum based active nanocomposite film reinforced with nanoclays.

In the present work, fenugreek seed gum (FSG)/clay nanocomposite films were prepared with nanoclays (Na+ montmorillonite [MMT], halloysite [HNT] and Nanomer® I.44 P [NM]) at different amounts (0, 2.5, 5.0 and 7.5g clay/100g FSG) by solution casting method and characterized. Increasing amount of nanoclay significantly (P<0.05) improved oxygen barrier and thermal properties of the biodegradable films. Agar diffusion tests revealed that FSG based nanocomposite films exhibited strong antimicrobial properties against foodborne pathogens namely Listeria monocytogenes, Escherichia coli O157:H7, Staphylococcus aureus and Bacillus cereus independently of clay type and concentration. In the case of mechanical properties, nanoclay incorporation up to 5% provided higher (P<0.05) tensile strength (TS) properties while elongation at break (EB) values of the films significantly (P<0.05) decreased in the presence of clay in the film matrix. SEM micrographs showed that especially lower levels (up to 5%) of nanoclay reinforcements provided a homogeneous and smooth film structure. In conclusion, FSG based nanocomposite films reinforced with nanoclays up to 5% showed a precious potential to be used in antimicrobial food packaging applications.

Effect of xanthan and locust bean gum synergistic interaction on characteristics of biodegradable edible film.

The present study was aimed to use different combinations of xanthan (XG) and locust bean gum (LBG) in the biodegradable edible film preparation by benefitting from their synergistic interactions for the first time. Concentrations of LBG, XG and glycerol of the optimized film sample were found to be 89.6%, 10.4% and 20%, respectively. At the optimum point the WVP, TS, E% and EM values of film were found 0.22gmmh-1 m2kPa, 86.97MPa, 33.34% and 177.25MPa, respectively. The optimized film was characterized for its physical, thermal and structural behavior. The scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FTIR) analyses exhibited miscibility and presence of interaction between polymers. In conclusion, XG and LBG interaction was used successfully to get biodegradable films and coatings with improved characteristics.

Recovery potential of cold press byproducts obtained from the edible oil industry: physicochemical, bioactive, and antimicrobial properties.

Physicochemical, bioactive, and antimicrobial properties of different cold press edible oil byproducts (almond (AOB), walnut (WOB), pomegranate (POB), and grape (GOB)) were investigated. Oil, protein, and crude fiber content of the byproducts were found between 4.82 and 12.57%, between 9.38 and 49.05%, and between 5.87 and 45.83%, respectively. GOB had very high crude fiber content; therefore, it may have potential for use as a new dietary fiber source in the food industry. As GOB, POB, and WOB oils were rich in polyunsaturated fatty acids, AOB was rich in monounsaturated fatty acids. Oil byproducts were also found to be rich in dietary mineral contents, especially potassium, calcium, phosphorus, and magnesium. WOB had highest total phenolic (802 ppm), flavonoid (216 ppm), and total hydrolyzed tannin (2185 ppm) contents among the other byproducts. Volatile compounds of all the byproducts are mainly composed of terpenes in concentration of approximately 95%. Limonene was the dominant volatile compound in all of the byproducts. Almond and pomegranate byproduct extracts showed antibacterial activity depending on their concentration, whereas those of walnut and grape byproducts showed no antibacterial activity against any pathogenic bacteria tested. According to the results of the present study, walnut, almond, pomegranate, and grape seed oil byproducts possess valuable properties that can be taken into consideration for improvement of nutritional and functional properties of many food products.

Molecular characterization of silver-stearate nanoparticles (AgStNPs): A hydrophobic and antimicrobial material against foodborne pathogens.

In this study, silver-stearate nanoparticles (AgStNPs) have been produced from silver nitrate solutions by replacing the nitrate by stearate ions and then reducing by thermal treatment. AgStNPs were characterized by particle size, zeta-potential, ATR-FTIR, contact angle and SEM (scanning electron microscopy) analyses. The mean particle size and zeta potential of AgStNPs were determined to be 69.22±7.30nm and +8.02±0.88mV. ATR-FTIR analysis showed characteristic IR bands of stearate, revealing the two strong peaks at 2848 and 2915cm-1 associated to symmetric (νs(CH2)) and asymmetric (νas(CH2)) stretching vibrations of methylene groups, respectively. On the other hand, the scissoring and rocking modes of methylene group were observed at 1470 and 718cm-1, respectively. Nanomorphological characterization by SEM revealed a layered morphology of AgStNPs. Contact angle measurements demonstrated that a contact angle of water drop on glass coated with AgStNPs was found to be 108.76°, which proved the strong hydrophobic properties of AgStNPs. AgStNPs seemed to be very effective in inhibiting foodborne pathogens (Salmonella Typhimurium, Escherichia coli O157:H7, Staphylococcus aureus, Listeria monocytogenes and Candida albicans). The results suggest the use of AgStNPs as a coating material to reduce biofilm or biofouling formation in terms of achieving appropriate food contact surfaces and higher hygiene/easier sanitation due to their strong hydrophobic and antimicrobial properties.

Application of non-linear models to predict inhibition effects of various plant hydrosols on Listeria monocytogenes inoculated on fresh-cut apples.

In this study, we studied the effects of some plant hydrosols obtained from bay leaf, black cumin, rosemary, sage, and thyme in reducing Listeria monocytogenes on the surface of fresh-cut apple cubes. Adaptive neuro-fuzzy inference system (ANFIS), artificial neural network (ANN), and multiple linear regression (MLR) models were used for describing the behavior of L. monocytogenes against the hydrosol treatments. Approximately 1-1.5 log CFU/g decreases in L. monocytogenes counts were observed after individual hydrosol treatments for 20 min. By extending the treatment time to 60 min, thyme, sage, or rosemary hydrosols eliminated L. monocytogenes, whereas black cumin and bay leaf hydrosols did not lead to additional reductions. In addition to antibacterial measurements, the abilities of ANFIS, ANN, and MLR models were compared with respect to estimation of the survival of L. monocytogenes. The root mean square error, mean absolute error, and determination coefficient statistics were used as comparison criteria. The comparison results indicated that the ANFIS model performed the best for estimating the effects of the plant hydrosols on L. monocytogenes counts. The ANN model was also effective; the MLR model was found to be poor at estimating L. monocytogenes numbers.

Efficacy of various plant hydrosols as natural food sanitizers in reducing Escherichia coli O157:H7 and Salmonella Typhimurium on fresh cut carrots and apples.

In the present study, inhibitory effects of the hydrosols of thyme, black cumin, sage, rosemary and bay leaf were investigated against Salmonella Typhimurium and Escherichia coli O157:H7 inoculated to apple and carrots (at the ratio of 5.81 and 5.81 log cfu/g for S. Typhimurium, and 5.90 and 5.70 log cfu/g for E. coli O157:H7 on to apple and carrot, respectively). After the inoculation of S. Typhimurium or E. coli O157:H7, shredded apple and carrot samples were washed with the hydrosols and sterile tap water (as control) for 0, 20, 40 and 60 min. While the sterile tap water was ineffective in reducing (P>0.05) S. Typhimurium and E. coli O157:H7, 20 min hydrosol treatment caused a significant (P<0.05) reduction compared to the control group. On the other hand, thyme and rosemary hydrosol treatments for 20 min produced a reduction of 1.42 and 1.33 log cfu/g respectively in the E. coli O157:H7 population on apples. Additional reductions were not always observed with increasing treatment time. Moreover, thyme hydrosol showed the highest antibacterial effect on both S. Typhimurium and E. coli O157:H7 counts. Inhibitory effect of thyme hydrosol on S. Typhimurium was higher than that for E. coli O157:H7. Bay leaf hydrosol treatments for 60 min reduced significantly (P<0.05) E. coli O157:H7 population on apple and carrot samples. In conclusion, it was shown that plant hydrosols, especially thyme hydrosol, could be used as a convenient sanitizing agent during the washing of fresh-cut fruits and vegetables.

Determination and improvement of microbial safety of wheat sprouts with chemical sanitizers.

In this study, total aerobic mesophilic bacteria (TAMB), total coliform (TC), yeasts and moulds (YM), and Escherichia coli, Salmonella, and Staphylococcus aureus counts of wheat seeds and sprouts germinated for 9 days under different relative humidity (RH) (90% and 95%) and temperatures (18 °C, 20 °C, and 22 °C) were determined. The disinfection capabilities of sodium hypochlorite (NaOCl) (100, 200, and 400 ppm) and hydrogen peroxide (H(2)O(2)) (3% and 6%) on wheat seeds/sprouts were also investigated. It has been found that native TAMB, TC, YM, and E. coli population significantly increased (p<0.05) with the germination; however, no Salmonella and S. aureus were detected on the seeds and/or sprouts. Again, increasing the temperature and RH resulted in a rapid proliferation of microorganisms. On the other hand, E. coli population could be completely eliminated by the treatment of different concentrations of NaOCl or H(2)O(2) before the germination of wheat seeds. Again, increasing the NaOCl and H(2)O(2) concentrations resulted in additional reductions of TAMB, TC, and YM population; and the highest reductions in sprouts were observed when the seed was soaked in 400 ppm NaOCl for 30 minutes followed by tap water wash and germination for 9 days. Population reduction of 1.46 log colony-forming unit (cfu)/g of TAMB, 1.97 log cfu/g of YM, and 0.84 log cfu/g of TC in sprouts was achieved when compared with the control. The chemical sanitization did not negatively affect the germination capability of the seeds. Therefore, soaking the seeds in 400 ppm of NaOCl for 30 minutes followed by a germination environment of 18 °C and 90% RH was found to be the most appropriate germination condition for wheat sprouts with reduced microbial population.