Synthesis and evaluation of some new demulsifiers based on bisphenols for treating water-in-crude oil emulsions

The present paper endeavors to synthesize nine types of demulsifiers based on bisphenols (bisphenol A (BA), bisphenol AC (BAC) and bisphenol CH (BCH)) having different ethylene oxide units (n = 27, 34, 45) namely; E (x + y) (where E represents BA, BCH or BAC and (x + y) which represents the ethylene oxide units (27, 34, 45)). The chemical structures of the prepared demulsifier were elucidated using FT-IR and ¹H NMR spectra. Effect of the chemical structure (hydrophobic and ethoxylated degree of hydrophilic parts) and the mechanism of demulsification process was investigated. The data were discussed on the light of the chemical structure of the demulsifiers and the factors, effecting the demulsification process. The efficiency of these demulsifiers was tested on water-in-oil emulsions (w/o) at different concentrations (100, 200 and 300 ppm), 7.4% asphaltene content and 30%, 50% and 70% water content. From the obtained data the best demulsifier was E(34)BA which shows 100% demulsification after 58 min at 30% water content and 300 ppm of the demulsifier.     

超声波强化原油脱盐脱水的实验研究

 考察了超声强化原油预处理工艺中的部分影响因素，包括电场强度、超声波频率、超声波功率、破乳剂用量、注水量等。超声波是促进原油破乳脱水的主要因素之一。实验结果表明，超声频率为10kHz的处理效果优于20kHz的；超声波功率和电场强度增加，均可使原油的脱盐脱水效率增加，当超声波功率为150W、电场强度为1.2kV/cm时，原油的脱盐脱水效果最佳，继续增加时，脱盐脱水效果反而降低；破乳剂用量也存在一最佳值(20~30μg/g)；注水量越多越有利于脱盐，但水含量增加, 因此采用5%（质量分数）左右的注水量能取得较理想的脱水脱盐效果。超声波强化原油脱水、脱盐工艺技术为炼油过程中原油预处理工艺提供了一种新的途径，保障了炼油生产的稳定与安全。     

Operating conditions for the electrolytic disinfection of process wash water from the fresh-cut industry contaminated with E. coli o157:H7

The effect of operating conditions (current density, recirculation flow rate and electrode doping level) on the efficacy of boron-doped diamond (BDD) electrodes to inactivate microorganisms and decrease chemical oxygen demand (COD) was studied in lettuce process wash water with a COD of 725 mg/L and inoculated with a 5-strain cocktail of Escherichia coli O157:H7. Changes in pathogen population, COD, pH, temperature, redox potential, and free and total chlorine were monitored in process wash water during treatments. Considering the specific characteristics of the washing step included in the fresh-cut processing, the disinfection of process wash water should be of fast action. A biphasic with a shoulder model was used to estimate shoulder length (Sl), log-linear inactivation rates (k_max1, k_max2), lowest population (N_f) and highest log reduction (HLR). Current density clearly influenced Sl, and k_max2; recirculation flow rate influenced Sl, k_max1, k_max2 and COD depletion; and doping level influenced N_f. No relationship was observed between inactivation parameters and chlorine concentration. Conditions including high current density (180 mA/cm²), high flow rate (750 l/h) and high doping level (8 000 μmol/mol) seems to provide a disinfection efficiency suitable to decrease the chance of bacterial cross contamination in the fresh-cut industries while saving on water consumption and decreasing the amount of wastewater effluents.     

Effective household disinfection methods of kitchen sponges

Several household disinfecting treatments to reduce bacteria, yeasts and molds on kitchen sponges were evaluated. Sponges were soaked in 10% bleach solution for 3 min, lemon juice (pH 2.9) for 1 min, or deionized water for 1 min, placed in a microwave oven for 1 min at full power, or placed in a dishwasher for full wash and drying cycles, or left untreated (control). Microwaving and dishwashing treatments significantly lowered (P < 0.05) aerobic bacterial counts (<0.4 log and 1.6 log CFU/sponge, respectively) more than any chemical treatment or control (7.5 CFU/sponge). Counts of yeasts and molds recovered from sponges receiving microwave (<0.4 log CFU/sponge) or dishwashing (0.4 log CFU/sponge) treatments were significantly lower than those recovered from sponges immersed in chemical treatments. Our study shows that microwaving and dishwashing treatments may kill foodborne pathogens in a household kitchen environment.     

Efficacy of oregano oil in the inactivation of Salmonella typhimurium on lettuce

This study was conducted to determine the efficacy of oregano oil in the inactivation of Salmonella typhimurium inoculated onto iceberg lettuce. The effect of washing with oregano oil (Oreganum onites), typical of Turkey, at three different concentrations (25, 40 and 75 ppm) and four different treatment times (5, 10, 15 and 20 min) on survival of S. typhimurium inoculated to fresh cut iceberg lettuce were determined at 20 °C and compared with a 50 ppm chlorine wash at the same conditions. The spot and dip inoculation methods for applying inoculum to iceberg and romaine type lettuce were evaluated and the effects of selective and nonselective media on the recovery of S. typhimurium were also examined. Populations of S. typhimurium recovered from spot and dip inoculated lettuce were not significantly different (p > 0.05). No significant differences were found between two different media, and two different lettuce types (p > 0.05). Reductions of S. typhimurium by washing with oregano did not exceed 1.92 logarithmic units regardless of the washing times and concentrations. The effectiveness of washing lettuce with 75 ppm oregano oil on inactivation of S. typhimurium was comparable with that affected by 50 ppm chlorine. The results suggested that oregano oil might be a suitable decontamination alternative to chlorine for lettuce.     

Decontamination of fresh produce by the use of slightly acidic hypochlorous water following pretreatment with sucrose fatty acid ester under microbubble generation

Treatment by slightly acidic hypochlorous water (SAHW) in combination of pretreatment with sucrose fatty acid ester under microbubble generation was effective for decontamination of lettuce. Sufficient contact time of SAHW containing 30 mg/L of available chlorine on reduction of viable counts of lettuce was determined to be 5 min. For 5 min at 18–20 °C, treatment with 30 mg/L of available chlorine in SAHW appeared more effective in the reduction of bacteria on lettuce compared with 15 mg/L. The treatment of lettuce at 50 °C with SAHW at 30 mg/L of available chlorine showed a 2 log reduction of bacterial counts without injury in the tissue. The treatment at 50 °C, SAHW also delayed browning on cut lettuce for the first 5–6 days of subsequent storage at 6 °C. Among two sucrose fatty acid esters tested, sucrose monopalmitate at 100 mg/L had a higher efficacy for pretreatment under microbubble generation. After pretreatment for 5 min with 100 mg/L sucrose monopalmitate under microbubble generation and subsequent treatment with SAHW at 50 °C for 5 min, viable counts of lettuce were decreased by about 3–4 logs. After the same treatment, Pseudomonas sp. predominant on lettuce decreased drastically. These results indicate the effectiveness of the combined treatments of sucrose fatty acid ester under microbubble generation and SAHW at 50 °C for decontamination of fresh produce.     

Efficacy of sanitizers in reducing Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes populations on fresh-cut carrots

Shredded carrots were inoculated with Escherichia coli O157:H7, Salmonella or Listeria monocytogenes and washed for 1 or 2 min with chlorine (Cl; 200 ppm), peroxyacetic acid (PA; 40 ppm) or acidified sodium chlorite (ASC; 100, 200, 500 ppm) under simulated commercial processing conditions. After washed, the carrots were spin dried, packaged and stored at 5 °C for up to 10 days. Bacterial enumeration was significantly (P ⩽ 0.05) reduced by 1, 1.5 and 2.5 log CFU/g after washing with ASC 100, 250 and 500 ppm, respectively. All sanitizers reduced pathogen load below that of tap water wash and unwashed controls. During storage at 5 °C the bacterial load of all treatments increased gradually, but to different extent in different treatments. ASC inhibited bacterial growth more effectively than the other sanitizers and also maintained the lowest pathogen counts (<1 log CFU/g) during storage. Organic matter in the process water significantly (P ⩽ 0.05) reduced the antibacterial efficacy of Cl, but not that of PA or ASC. Therefore, ASC shows the potential to be used as a commercial sanitizer for washing shredded carrots.     

重质原油电脱盐用破乳剂的合成及评价

重质原油具有胶质和沥青质含量高、氯盐含量高、黏度高和界面膜稳定性好等特点,利用传统的破乳剂破乳时,破乳效果较差。针对重质原油电脱盐破乳,合成了WS系列破乳剂,对其进行了红外光谱表征、羟值和实际相对分子质量的测定以及电脱盐实验评价。结果表明,合成的WS系列破乳剂产率在98%以上,其中WS-5破乳剂对塔河油田重质原油的破乳效果最好;在破乳剂加量60 mg/L、温度155℃、注清水质量8%、搅拌时间4 min、电场强度1100 V/cm、停留时间90 min、三级电脱盐的条件下,原油盐质量浓度由153.2 mg/L降至2.76 mg/L,脱后原油含水量为0.28%。WS-5破乳剂对塔河油田重质原油电脱盐效果比较理想,具有潜在的应用价值。     

Enhanced removal of Methylene Blue by electrocoagulation using iron electrodes

The removal of pollutants from effluents by electrocoagulation has become an attractive method in recent years. The study deals with the enhancement of removal of Methylene Blue dye by using an electromagnetic field during the electrocoagulation process. Effects of electrolyte concentration, dye concentration, intensity and the direction of the electromagnet on the decolorization efficiency have been investigated. The formed ferric hydroxide flocs trap colloidal particles and make solid–liquid separation easier during the next stage. The electrocoagulation stages must be optimized in order to design an economically feasible process. The results showed that the optimum electrolysis was 10–20 min at a current density of 8 mA/cm², while the optimum concentration of the electrolyte (NaOH) was found to be 2 wt.% when the dye concentration was 50 mg/L. The utilization of an electromagnetic field enhanced the dye removal due to the induced motion of paramagnetic ions inside the solution. The power consumption required to remove the dye was reduced by 45% in the case of applying an electromagnetic field.     

Characterization and modeling of a crude oil desalting plant by a statistically designed approach

Oil produced in most of oil fields is accompanied by water and dissolved salts, mainly NaCl, which can cause considerable operational problem. Therefore, desalting and dehydration plants are often installed in crude oil production units to remove water soluble salts from an oil stream. This paper investigates experimentally the effect of five parameters (demulsifying agent concentration, temperature, wash water dilution ratio, settling time and mixing time with wash water) on performance of the desalting/dehydration process. The performance was evaluated by calculating the Salt Removal Efficiency (SRE) and the Water Removal Efficiency (WRE) based on the five process parameters. In order to investigate the effect of these parameters on desalting/dehydration efficiencies a 2^6 − 1 fractional factorial design with five other experiments at the center of the design for analysis of variance was applied. Based on the statistical analysis, SRE was expressed by a model for the whole range of variables while WRE was expressed with two models, each is valid in a part of variable domains. The models were satisfactorily evaluated with plant experimental data. For the SRE, the optimum values of demulsifying agent concentration, temperature, wash water dilution ratio, settling time and mixing time with wash water were fond to be 15 ppm, 77 °C, 10%, 3 min and 9 min respectively. As a result the optimum value of 93.28% salt removal efficiency was found. This value was 94.80% and 89.57% for water removal proposed models.     

Survival and growth of Listeria monocytogenes in lubricants used in the food industry

The survival and growth of three Listeria monocytogenes strains in 10 lubricants (synthetic and mineral-oil based) used in the food industry, and rapeseed oil, was investigated at room temperature (20 °C) and refrigerated (5 °C). Additionally, the transfer of L. monocytogenes from lubricants to stainless steel surfaces and vice versa was investigated. Though the amount of L. monocytogenes in most lubricants, both pure and soiled, decreased significantly (p < 0.05) during the 14 d test period, lubricants may act as sources of contamination on the basis of the results obtained on the survival of L. monocytogenes. In general, temperature had significant effect (p < 0.05) on listericidal effect of lubricants contrary to soiling (p > 0.05), however the effect of both factors was dependent on lubricant (p < 0.05). The results clearly showed that L. monocytogenes survived in synthetic conveyer belt lubricant diluted in water. In addition, L. monocytogenes was transferred significantly (p < 0.05) from stainless steel surfaces into conveyer-belt lubricants and into mineral-oil based hydraulic oil.     

Emerging sanitizers and Clean Room packaging for improving the microbial quality of fresh-cut ‘Galia’ melon

This study evaluated how traditional or new sanitizers, alone, or in combination with the use of a Clean Room (CR), affected the respiration rate, microbial, nutritional and sensorial quality of fresh-cut ‘Galia’ melon. Melon pieces were packed in polypropylene trays under passive modified atmosphere (7.4 kPa O₂ + 7.4 kPa CO₂) and stored up to 10 days at 5 °C. The following treatments were performed: 150 mg/l chlorine (control) for 1 min; 80 mg/l peracetic acid (PAA) for 1 min; ozonated water (0.4 mg/l) for 3 and 5 min. The combinations of: ozonated water and PAA; 150 mg/l chlorine and packaging in CR; ozonated water for 3 min and package in CR; ozonated water for 3 min + PAA and packaging in CR were also studied. Throughout the shelf-life psychrotrophic, mesophilic, Enterobactericeae, lactic acid bacteria, moulds and yeast growth were determined. The use of PAA provided the lowest microbial load, but this sanitizer decreased the total vitamin C and the antioxidant activity. Nevertheless, the combination of PAA with 0.4 mg/l of ozonated water (3 min) could be a good substitute of use of chlorine. This treatment was effective in reducing the microbial counts, maintaining the antioxidant compounds and respiration rate and maintained the sensorial quality of the product during the 10 days at 5 °C. Treated product packaged in a CR did not show increased treatment effect, probably due to air quality in the laboratory. The use of CR just for the packaging of the melon pieces did not offer any additional advantage. However, the utilization of CR in an industrial environment during all processing steps (from washing to packaging) should be investigated for potential benefits.     

Effect of organic acids,hydrogen peroxide and mild heat on inactivation of Escherichia coli O157:H7 on baby spinach

Minimally processed baby spinach contaminated with Escherichia coli O157:H7 has been associated with multiple outbreaks of foodborne illnesses recently. Chlorinated water is widely used to wash vegetables commercially, but this washing procedure has limited efficacy and can lead to the formation of carcinogenic substances. This study was conducted to determine the effects of organic acids and hydrogen peroxide alone and in binary combinations with or without mild heat (40 and 50 °C) on the inactivation of Escherichia coli O157:H7 on baby spinach. Baby spinach leaves were dip-inoculated with E. coli O157:H7 to a level of 6 log CFU/g and stored at 4 °C for 24 h before treatment. Individual washing solutions (1% and 2% lactic acid [LA], citric acid [CA], malic acid [MA], tartaric acid [TA], acetic acid [AA], hydrogen peroxide [H₂O₂] as well as binary combinations of LA, CA, MA and H₂O₂ at final concentrations of 1% were used to decontaminate spinach leaves at 22, 40 or 50 °C for 2–5 min to test their efficacy in reducing E. coli O157:H7. Chlorinated water (200 ppm free chlorine) decreased the population of E. coli O157:H7 on baby spinach by only 1.2–1.6 log CFU/g, which was not significantly different from DI water washing. Washing with 1% LA at 40 °C for 5 min was the most effective treatment achieving a 2.7 log reduction of E. coli O157:H7 which is significantly higher than chlorine washing. Washing with LA + CA or LA + HP at 40 °C for 5 min was equally effective against E. coli O157:H7, resulting in a 2.7 log reduction of E. coli O157:H7. The application of mild heat significantly enhanced the efficacy of washing solutions on the inactivation of E. coli O157:H7. There was, however, no significant difference between treatments at 40 °C for 5 min and 50 °C for 2 min. The results suggested that the use of organic acids in combination with mild heat can be a potential intervention to control E. coli O157:H7 on spinach.     

Aqueous extracts of Hibiscus sabdariffa calyces as an antimicrobial rinse on hot dogs against Listeria monocytogenes and methicillin-resistant Staphylococcus aureus

Contamination of ready-to-eat meat products by foodborne pathogens is a major concern in the food industry. Novel methods to control foodborne pathogens are made necessary by continuing outbreaks as well as the development of antibiotic-resistant pathogens. Hibiscus sabdariffa extracts could be useful as a natural source of antimicrobial rinse on ready-to-eat products to control pathogens. In this study, lyophilized Hibiscus flower extracts were examined for their antimicrobial activity as a rinse on all-beef hot dogs against Listeria monocytogenes and methicillin-resistant Staphylococcus aureus (MRSA). Beef hot dogs were dip inoculated in overnight cultures of 1:1 mixtures of L. monocytogenes strains Scott A and 101 or MRSA strains ATCC 33591 and ATCC 33593 and were placed at 4 °C overnight to allow for bacterial attachment. Hot dogs were rinsed with extracts (120, 240 mg/mL) or water (control) for 5, 15, 30, or 60 min and then plated immediately (0 h; no storage) or stored at 4 °C overnight and plated at 24 h. Serial dilutions were plated in duplicate on both TSA and selection media, Modified Oxford (Listeria) or Baird Parker (MRSA), and the entire experiment was replicated 3 times. Higher extract concentrations, longer rinse times, and longer storage times were the most effective at inhibiting and/or killing L. monocytogenes and MRSA on hot dogs. L. monocytogenes was reduced to ca. 1.5 log CFU/g while MRSA was reduced to undetectable levels following rinsing of hot dogs with extracts at 240 mg/mL for 60 min and stored for 24 h. Both L. monocytogenes and MRSA were reduced ca. 2 log CFU/g following rinsing of hot dogs with extracts at 120 mg/mL for 60 min and stored for 24 h. This research demonstrates the effectiveness of Hibiscus extracts against L. monocytogenes and MRSA as an antimicrobial rinse on ready-to-eat meat products.     

Effect of ultrasound treatment on fruit decay and quality maintenance in strawberry after harvest

The effects of ultrasound treatment on fruit decay and physiological quality of strawberry fruit were investigated. Freshly harvested strawberries were treated with 0, 25, 28, 40 or 59 kHz ultrasound at 20 °C for 10 min and then stored at 5 °C for 8 days. The results showed that 40 kHz ultrasonic treatment significantly reduced decay incidence and numbers of microorganism. Ultrasound treatment also inhibited the decrease of firmness and maintained significant higher levels of total soluble solids (TSS), total titratable acidity (TA) and vitamin C. Treatments with 25 and 28 kHz ultrasound had no significant effects on fruit decay and quality deterioration of strawberry fruit. Thus, ultrasound treatment has potential to extend shelf-life and maintain quality in strawberry fruit.     

原油电脱盐破乳剂的筛选与EC2425A油溶性破乳剂的应用

针对加工的原油品种变化后，原油电脱盐装置使用的水溶性破乳剂消耗量大、脱盐罐排水中油含量高的现状，在电脱盐装置上对几种油溶性破乳剂进行了筛选，筛选出的EC2425A型油溶性破乳剂不仅消耗量低，而且脱盐污水中的油含量也降低。工业应用表明，破乳剂加入量（以原油中破乳剂浓度表示）控制在5mg／L时，能够满足工艺指标要求（脱后原油盐浓度不大于3mg／L，水质量分数不大于0．3％），并且脱盐污水中油浓度仅为200mg／L左右。     

Antibacterial effect of black seed oil on Listeria monocytogenes

Listeria monocytogenes is a major foodborne pathogen in the United States. Effective methods for reducing L. monocytogenes in foods would reduce the likelihood of foodborne outbreaks of listeriosis, and decrease economic losses to the food industry. Nigella sativa is a herbaceous plant, whose seeds (black seed) have been used as a spice and condiment in foods in the Middle East. The objective of this study was to determine the antibacterial effect of black seed oil on twenty strains of L. monocytogenes by disc diffusion method. A population of 7.0 log CFU of each strain of L. monocytogenes was inoculated on duplicate plates containing antibiotic medium one agar. The plates were allowed to dry at room temperature for 15 min. Three discs (6 mm diameter), each impregnated with 10 μl of black seed oil, vegetable oil (oil control), or gentamicin (positive control) were placed on each inoculated plate. The plates were incubated at 37 °C for 24 h, and were observed for zones of L. monocytogenes growth inhibition. Black seed oil exhibited a strong antibacterial activity against all the strains of L. monocytogenes, yielding a significantly (P<0.01) larger inhibition zone than that of gentamicin. The mean zones of inhibition produced by black seed oil and gentamicin were 31.50 ± 1.0 and 14.80 ± 0.50, respectively. The vegetable oil had no inhibitory effect on L. monocytogenes. Results indicate that black seed oil could potentially be used to inhibit L. monocytogenes, but appropriate applications in foods need to be validated.     

Investigations on the essential oil of Lippia rugosa from Cameroon for its potential use as antifungal agent against Aspergillus flavus Link ex. Fries

Lippia rugosa essential oil was tested for its effectiveness against Aspergillus flavus on artificial growth media. The chemical composition of the oil was determined by gas chromatography–mass spectrometry (GC–MS). Geraniol (51.5%), nerol (18.6%) and geranial (10.4%) were the main components of Lippia oil. After 8 days of incubation on essential oil supplemented medium, mycelium growth of A. flavus was totally inhibited by 1000 mg l^?1 of L. rugosa essential oil. The effect of essential oil on aflatoxin B₁ synthesis was evaluated in SMKY broth. The medium supplemented with different essential oil concentrations, was inoculated with A. flavus mycelium and incubated at 25 °C. After 2, 4, 6 and 8 days, aflatoxin B₁ (AFB₁) was quantified in the supernatant using Enzyme Linked Immuno-Sorbent Assay (ELISA). Results showed that aflatoxin B₁ synthesis was inhibited by 1000 mg l^?1 of L. rugosa essential oil after 8 days of incubation. The effect of the EO on the H⁺-ATPase pumping membrane was also evaluated in the presence of several concentrations of oil (200–2000 mg l^?1) by monitoring glucose-induced acidification of the external medium. L. rugosa essential oil at the concentration of 2000 mg l^?1 completely inhibited the activity of this enzyme. These data suggest that the essential oil of L. rugosa is a fungicidal for A. flavus and its possible cellular target include the H⁺-ATPase.Results obtained in the present study indicate the possibility of exploiting Lippia rugosa essential oil in the fight against strains of A. flavus responsible for biodeterioration of stored foods products.     

Effects of pulsed electric field treatments on quality of peanut oil

The effects of pulsed electric fields (PEF) treatment on physicochemical properties of peanut oil were investigated in this paper. Compositions of fatty acid, acid value (AV), peroxide value (PV), as well as carbonyl group value (CGV) of various PEF-treated peanut oil samples with different storage time were determined by GC/MS and AOCS standard methods. GC/MS analysis showed that little change of the oil composition was observed after PEF treatment. However, after being treated by various PEF treatments and stored at 40 °C for 100 days, the biggest increment of AV was 0.69 mg g⁻¹, which was lower than that of untreated peanut oil (0.79 mg g⁻¹). The PV significantly increased from 4.8 meq kg⁻¹ untreated oil to 11.5 meq kg⁻¹ PEF treated oil (50 kV cm⁻¹). And the increase extent of CGV of oil samples during the 100 d’ storage period was decreased with increasing electric field strength. During the storage period, the differences of AV, PV, and CGV of PEF-treated sample during storage period were less than that of untreated oil, which implied that the PEF treatment could restrain the speed of lipid oxidation reaction thus extending the shelf-life of oil rich products.     

Antimicrobial activity of clove (Syzgium aromaticum) oil in inhibiting Listeria monocytogenes on chicken frankfurters

The ability of Listeria monocytogenes to survive and grow at refrigeration temperature in some ready to eat (RTE) poultry products is a public health concern. The inhibitory effect of clove oil (1% and 2%, v/w) applied to the surface of RTE chicken frankfurters was determined on seven strains of L. monocytogenes inoculated at low (10²–10³ cfu/g) or high cell numbers (10⁴–10⁶ cfu/g), and stored at 5 °C for 2 weeks or at 15 °C for 1 week. All strains of L. monocytogenes survived and grew on control frankfurters at 5 °C and 15 °C but growth was inhibited under both storage conditions in the presence of either 1% or 2% clove oil. Depending on the sensory considerations, the addition of clove oil to frankfurters may be an effective strategy to control L. monocytogenes in chicken frankfurters.