Study on the structure and properties of modified silk with ultraviolet absorbent北大核心CSCD

The silk fiber has an irreplaceable position in textile fibers and related silk fabrics have the advantages of light and airy texture good moisture absorption and breathability comfort in wear etc. It is also widely used in other fields such as the biomedical sector. However silk also has its own limitations poor light resistance and susceptibility to ultraviolet light especially the ultraviolet light of 290-400 nm wavelength in daylight such as under which condition it is prone to yellowing and photodegradation. The yellowing of silk is due to the photo-oxidation of tyrosine and tryptophan in silk protein under the action of ultraviolet light from sunlight and due to the production of yellow substances which affects the whiteness of silk. In addition from the molecular structure of silk most of the amino acids susceptible to UV light are distributed in the amorphous region. As the amorphous region is affected the structure of the crystalline region is also gradually relaxed the local degradation begins and the silk protein macromolecule chain is cleaved which leads to the decrease of the mechanical properties of silk fibers and accelerates the aging of silk fibers and fabrics. Therefore it is necessary to modify the silk products outside the anti-purple line. The current methods used to modify silk are mostly for post finishing modification including coating impregnation and chemical grafting methods but these methods often affect the original color or feel of the fabric and the durability of the modified effect is also poor. The feeding method is a green method to obtain modified silk by spraying mulberry leaves or artificial feed mixed with modifier which is ingested by silkworm and transferred to silk gland. In this study five aminobenzene UV absorbers were used as exogenous additive food for silkworms. The effect of molecular polarity on the transport of modifiers to silk glands was investigated and their effects on silkworm development and silk structural properties were studied. It was found that the aminobenzene UV absorbers were more easily transferred to the central silk gland silk glue and less to the posterior silk gland (fibroin). 4-dimethylaminobenzoic acid was found to be the highest in the posterior silk gland with a content of 3. 27 μg / strip. The cocoon width and cocoon quality of this group were significantly lower than those of the control group and the silk gum content was increased when this group was used as the study object. Compared with the control group the relative content of β-folded structure and crystallinity of the silk in the addition feeding group decreased slightly. The silkworm silk in the feeding group showed a certain UV absorption ability. After 330 h UV irradiation the breaking strength and elongation of the control group decreased by 48. 95% and 43. 52% respectively while those of the feeding group decreased by 42. 03% and 34. 18% respectively. In this paper UV absorbers were added to silkworms to obtain modified silk mainly focusing on the transfer of the modifier to the silk gland and the structural properties of the modified silk only for the most UV absorbers to enter the silk gland of the posterior group of silk. Other properties of the modified silk such as washing resistance have not been studied and some more in-depth studies are required. For instance it needs to be studied in depth for the limited absorption of exogenous additives by silkworms additive food's being not always absorbed by silkworms and transferred to the silk gland and the mechanism of action between the additive food and silk protein after the former's entering the silk gland. © 2022 Authors. All rights reserved.     

Effect of Interacting Abiotic Storage Conditions on Respiration, Dry Matter Losses and Aflatoxin B1 Contamination of Stored Turkey’s Shelled Hazelnuts (英文原文)(Online First, Recommended Article)

Hazelnuts are an economically important nut which is consumed world-wide. It is prone to infection by Aspergillus flavus and contamination with aflatoxins. Taking Tukey’s hazelnuts as a research object, the objective of this study were to (a) quantify respiration rates and (b) dry matter losses (DMLs) and (c) aflatoxin B1 (AFB1) contamination of naturally stored shelled hazelnuts at different temperatures and water availabilities. Subsequently, shelled hazelnuts were inoculated with additional A. flavus inoculum prior to storage to examine effects on dry matter losses and on AFB1 contamination. Maximum respiration of hazelnuts and associated mycoflora was under wetter conditions of 0.90~0.95 water activity (aw = 12.5%~18% moisture content). This resulted in between approx. 10% DML at 25 and 30 ℃ after 5 days storage. Inoculation and storage of shelled hazelnuts + A. flavus inoculum resulted in similar patterns of respiration with optimal levels at 25~30 ℃ and >0.90 aw. Indeed, AFB1 contamination was highest at the maximum water levels tested of 0.90 aw. Indeed the contamination level exceeded the legislative limits set by the EU for AFB1 contamination of these nuts. Correlation between DMLs and all the AFB1 data in both sets of studies showed that very small changes in DML due to poor drying or storage of ≥0.6% resulted in AFB1 contamination levels exceeding the EU legislative limits. Thus, efficient drying and safe monitored storage is necessary to minimise the risk of AFB1 contamination in this economically important commodity and to avoid exposure of consumers to such toxins.     

A Kinetic Model for Describing the Effect of Proteins on the Air-Water Interface Tension

The main objective of this work was to develop a kinetic model to describe the variation of the surface tension in an air-water interface due to the adsorption of proteins from different origins and to identify quantitatively the relevant parameters, it was considered that the processes of adsorption, unfolding and reordering of the protein molecule in the interface occur simultaneously. The model used in the present work to calculate the surface tension postulates the existence of two simultaneous processes, adsorption and protein rearrangement represented with an equation of first order with two exponential components. The relevant parameter of the equation are ka and kr-the rate constants of the two first order kinetic phases that correspond to both conformational states of the protein, adsorption and rearrangement during the process of variation of the surface tension, and the amplitude parameters Aa and Ar. The results suggest that the kinetic model for the variation of the surface tension of protein solutions proposed in this work, with two simultaneous first order processes, is more appropriate than previous models to describe such variation.     

Optimization of the Design and Drying Process Adapted to Pineapple Slices

The present work is a study on the influence of temperature and the velocity of air on the drying kinetics of pineapple slices. The main objective is to define from this drying kinetics rules to help a designer choose an adequate principle or drying configuration and optimize the design of dryers adapted to the use of it. The experiments were made in an electric dryer using a parallel flow system. The air was used at three different temperatures （40, 50 and 60 ~C） and at four different velocities （0.27, 0.5, 1 and 1.8 m/s） during the experiment. The results show that an increase of 10 ℃ of the drying temperature reduced the drying time by 45% and increased the drying velocity by 30%. On the set of air velocities tested, it was noticed that the influence of air velocity on drying was more striking at the beginning than at the end of the drying process （variation of less than 20%）. Whatever the variation of parameters during the drying process, the best performance was observed when the products water content during the drying process was between 50% and 80%.     

Effects of Fermentation and Drying on the Fermentation Index and Cut Test of Pulp Pre-conditioned Ghanaian Cocoa （Theobroma cacao） Beans

Investigations were conducted to establish effects of fermentation and drying on the fermentation index （FI） and cut test of pulp pre-conditioned Ghanaian cocoa beans using a 4 x 3 full factorial experimental design with the principal factors being pod storage （0, 3, 7 and 10 d） and fermentation time （0, 3 and 6 d） to study the changes occurring during the fermentation process. The study also used a 4 x 3 full factorial design with pod storage （0, 3, 7 and 10 d） and drying time （0, 3 and 7 d） being the principal factors investigated to study the changes occurring during the drying process. FI and cut test of the beans were studied during fermentation as well as the drying process. FI of the beans increased significantly with pod storage and fermentation but decreased slightly during drying. FI of the unfermented beans increased slightly from 0.674 for the unstored pods to 0.763 after 10 days of pod storage. The FI of the fermented beans （six days fermentation） also increased from 1.390 for the unstored pods to 1.424 for pods stored for 10 days. It decreased from 1.389 at the start of drying for the unstored pods to 1.105 for pods stored for 10 days at the end of drying （seven days）. FI of all the beans were however, above 1.0 at the end of fermentation and drying for all pod storage treatments. Cut test revealed that storage of pods for 3, 7 and 10 days increased the percentage of brown beans by 66%, 94% and 72%, respectively, by the sixth day of fermentation. Percentage of brown beans decreased to 61%, 76% and 63%, respectively, for pods stored for 3, 7 and 10 d at the end of drying （seven days）. Cocoa pods can be stored for up to 10 days, fermented for six days and dried for seven days with the necessary formation of brown pigments characteristics of well fermented and dried cocoa beans.     

Green and Effective Ammonium Carbonate-assisted Process for Drying Hemicellulose Obtained through Alkali Extraction of Bleached Bamboo Kraft Pulp

Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually present as a spent liquor,such as the prehydrolysis liquor of the prehydrolysis kraft dissolving pulp production process and the alkali extraction liquor of the cold caustic extraction of pulp fibers.Due to its dilute nature,hemicellulose needs to be dried for practical utilization,and this is challenging.In this study,cellulose and hemicellulose in a bleached bamboo kraft pulp were separated using an alkali extraction process.Hemicellulose obtained from the extraction liquor was dried by an ammonium carbonate-assisted drying process.The effects of drying time and drying temperature were determined.Structure of the hemicellulose obtained by the ammonium carbonate-assisted drying process was similar to that of original hemicellulose,as revealed by detailed Fourier transform infrared and X-ray diffraction analyses.The novel drying method was more energy efficient and required a shorter drying time than the conventional freeze drying method,and the excellent solubility in alkaline solutions favored the chemical modification of hemicellulose.The dried hemicellulose can be used as a renewable raw material for the preparation of hydrogels and other substances such as bioethanol/biochemicals and biodegradable films.     

特征峰斜率还原模型快速测定水产品中硝酸盐含量的研究(英文)

Nitrate is closely related to the content of nitrosamine,which is known to be toxic and is determined in aquatic products.In this paper,a new sensitive UV spectrophotometry method based on K-model for rapid determination of nitrate in different kinds of samples was developed.The UV characteristic absorbance points of nitrate were selected and optimized.Under the optimized experimental conditions the calibration equation and K-model were obtained.The calibration curve is linear in the concentration range of 1 to 100μg/ml(R2=0.9973).This method was found to exhibit good accuracy,precision and repeatability.The developed method could be applied to the determination of nitrate in aquatic products and other food products.     

论中国白酒的贮存容器

In 1955, the first liquor -brewing congress was held in Beijing , in which the liquor storage time was defined : three years for the famous liquor, one year for the high-quality liquor and ten days for the ordinary liquor. The liquor store vessels are various in diffrent enterprises, then which is more suitble for liquor s store ? The following article will brief introduce some types of store vessels.We will join WTO at the 21 st century. With the coming of opportunity and challenge, the competition in liquor market must be more fierce. Under the circumstances,we should adopt appropriate measures to improve economic benefit.     

臭氧冰在水产品保鲜中的研究(英文)

The effects of ozone ice on the shelf life of Pseudosciaena crocea and cuttlefish,stored under refrigeration(4 ± 0.5℃) were studied by monitoring the microbiological,chemical and sensory changes for a period of 17 days.Results showed that the shelf life could be lengthened 4～5 days preserved by 4mg/kg ozone ice.The total volatility basis nitrogen(TVB-N) was reduced and the bacteria colony was decreased by 92%.The bactericidal effectiveness of ozone ice is strong enough to attain better preservation effect.As a convenient,simple and environmental friendly method,it could be used in the preservation and transportation of fishery products.     

Experimental Investigation on Simultaneous Dry Blanching and Drying of Mushroom Slices Using Microwave Enhanced Hot Air Heating System

The study evaluated the feasibility of using microwave enhanced hot air heating system for simultaneous dry blanching and dehydration of mushroom slices. The technology involves application of microwave energy at the beginning of dehydration process to inactivate enzymes as well as to remove a certain amount of moisture at the same time and then followed by hot air drying to complete the process. The study investigated effects of different processing parameters, i.e., microwave power level and exposure time on dehydration and quality characteristics of mushroom slices. Mushroom slices were pretreated with different microwave power levels of 240, 360 and 480 W for 1, 3 and 5 min before the hot air-drying. The optimum range of the microwave power level and pretreatment time was found to be 360 W, 3 min and 360 W, 1 min in obtaining the maximum and minimum levels of response parameters.     

Ultrasound-assisted Biodiesel Production from Waste Cooking Oil at Room Temperature

Waste cooking oil (WCO) is considered to be a promising alternative for vegetable oils that have been traditionally used for biodiesel production. In this study, WCO with a fairly high free fatty acid content was transesterified into biodiesel in a one-step procedureat room temperature (25℃ ) under ultrasound irradiation and in the presence of potassium hydroxide (KOH) as catalysts. Response surface methodology (RSM) was used to investigate the effects of the methanol/oil molar ratio, reaction time, and catalyst loading on the fatty acid methyl ester (FAME) yield and the biodiesel yield. The optimal reaction conditions for the production of WCO biodiesel were found to be a methanol/oil molar ratio of 8.6:1, a reaction time of 25 min, and a catalyst loading of 2.43 wt%. Under these optimal settings, the FAME and biodiesel yields were 96.4% and 92.7%, respectively. The properties of the resultant WCO biodiesel, including kinetic viscosity, acid number, water content, and flash point, were measured according to ASTM D6751 standards. The obtained results provide useful information for the large-scale production of WCO biodiesel.     

Cyanide Contents of Leaves of Commonly Consumed Cassava Varieties from Three Geographical Regions of Ghana

Consuming a cyanogenic plant is an etiological factor to the persistence of iodine deficiency in the post salt iodization phase. Ghana, notably the Northern belt, still reports of iodine deficiency after 14 years of mandatory consumption of iodized salt by an Act of Parliament. The study aimed at determining the cyanide contents of leaves of commonly consumed cassava varieties in Ghana and investigating the effects of some environmental factors on cyanide content. Three communities each from Southern, Middle and Northern Ghana served as the study sites from where young, non-diseased and fully-spread cassava leaves were sampled from plants of commonly consumed cassava varieties. Cyanide was analyzed by the standard color~metric method based on the chloramine-T/pyridine-barbituric acid protocol （4500-CN E）. Cassava leaves from Northern Ghana had significantly higher mean cyanide content （177.22 ± 20.82 ppm） than those from Middle （130.83± 33.00 ppm） and Southern Ghana （127.24 ± 37.54 ppm） （P 〈 0.001）. Two-factor ANOVA showed significantly higher adverse environmental effects on cyanide contents of leaves of unimproved cassava varieties than improved ones （R2 = 0.627, P = 0.023）. From multiple regression analysis, temperature was the most significant environmental factor explaining 33% of the variability in cyanide content （R2 = 0.331, P = 0.002）, followed by altitude （R2 = 0.106, P = 0.049） and rainfall （R2 = 0.084, P = 0.062）. The high cyanide contents of cassava leaves from Northern Ghana, due principally to the high atmospheric temperature, may be a contributory factor to the high prevalence of goiter and the persistence of iodine deficiency in that geographic region.     

Liquefaction of Rice Straw with Ethylene Carbonate

In this study,rice straw(RS) was liquefied by ethylene carbonate(EC) using H_2SO_4 as a catalyst.The effects of various process conditions on the liquefaction characteristics were investigated by FT-IR and residue content analysis.The results show that cellulose and lignin are degraded during the liquefaction process and large amounts of groups are generated.In addition,it is difficult to effectively liquefy RS by using EC alone as the liquefying agent without other additives.Compared to water addition on liquefaction,the residue content can be significantly reduced up to 30% by adding H_2O_2.It has also been proved that the liquor ratio(RS/EC,w/v) of 1∶5 with H_2O_2 as an additive at 145℃ for liquefaction time of 60 min in the presence of H_2SO_4 can accelerate the liquefaction process and high liquefaction yield can be obtained.     

Preparation of Lignin Based Anion Exchanger for Nitrate and Phosphate Removal

Tertiary amino alkali lignin (TA-AL) was successfully synthesized by a two-step approach;its application as an adsorbent for nitrate and phosphate ions in effluents was investigated.TA-AL was characterized by FT-IR,zeta potential,SEM,and elemental analysis.Kinetic and equilibrium adsorption isotherms were determined to investigate the adsorption capacity of TAAL.The results revealed that TA-AL had a very strong adsorption capacity towards anions;the value of pHPZC (PZC,point of zero charge) was about 9.2.The adsorption of nitrate and phosphate ions was related to effluent pH and initial anion concentration.The maximum absorption of nitrate and phosphate ions was about 26.9 and 18.4 mg/g when the initial concentration of the ions was 50 mg/L.The adsorption kinetics conformed to the pseudo-second-order kinetic equation,and the equilibrium data were suitably expressed by the Freundlich model.The regeneration studies confirmed that the lignin-based material was a promising adsorbent for nitrate and phosphate ions in water.     

Etherification of Alkali-pretreated Sugarcane Bagasse Cellulose in Tetrahydrofuran

Sugarcane bagasse (SCB) is an important by-product in the sugar industry. It is a source of cellulose fibers or cellulose for paper mills and textiles factories. In this study, SCB was ethyl etherified in tetrahydrofuran (THF) after alkali pretreatment. The alkali concentration for the pre-treatment, the ratio of ethyl bromide (EtBr) to dried SCB in the reaction, reaction time, and temperature were investigated for the etherification of SCB. The ethoxyl content and characterization of the product were determined using headspace gas chromatography (HS-GC), Fourier Transform Infrared (FT-IR) and ¹³C-NMR spectroscopy, respectively. It was found that SCB was well-etherified with EtBr in alkali-THF. Upon ethylation of SCB, the ethoxyl content of the product was high when the alkali concentration and the ratio of EtBr to dried SCB were controlled from 50% to 75% and 4:1 (V/w) to 6:1 (V/w), respectively. The reaction occurred optimally when the temperature was controlled below 110℃; above this temperature, the degree of etherification decreased. The thermal stability of ethylated SCB was higher than that of SCB but slightly lower than that of commercial ethyl cellulose. Ethylated SCB has the potential to form composites with many materials because it is soluble in a wide variety of solvents.     

Preparation and characteristics of bombyx mori sericin / tussah silk fibroin / gelatin-based blended antibacterial films北大核心CSCD

A large number of wound dressings are currently used in the treatment of burns chronic ulcers etc. An ideal wound dressing should prevent dehydration of the wound and retain a favorable moist environment at the wound interface. It should have good antibacterial properties and be easily removed without trauma too. Wound dressings are generally made of readily available bio-materials that require minimal processing possess nontoxic non-allergenic and antimicrobial properties as well as promote wound healing. Clinically collagen chitin chitosan etc. are usually used as materials for producing wound dressings as these materials are capable of accelerating the healing processes at molecular cellular and individual levels. Tussah silk fibroin bombyx mori sericin and gelatin non-toxic and extensive have good bio-compatibility degradability and film-forming properties which are conducive to cell adhesion. In order to prepare safe biofilms with excellent antibacterial properties we prepared a kind of bombyx mori sericin / tussah silk fibroin / gelatin BS-TSF-GEL blended film by using tussah silk fibroin bombyx mori sericin and gelatin as bio-based materials and polyethylene glycol 200 as the cross-linking agent. Firstly we designed the single factor experiment and orthogonal experiment to optimize the preparation process of the BS-TF-GEL blended film. On this basis the blended film was modified with ethanol of different concentrations to improve its strength and crystallinity. The structure and properties of the blended film were characterized by measuring the dissolution loss rate tensile properties microscopic morphology and crystal structure. Finally antimicrobial peptides were loaded by adsorption to obtain the BS-TSF-GEL antimicrobial film. The results showed that the ratio of the optimum formula for the (BS-TSF-GEL) blended film required a mixture of bombyx mori sericin (4. 50 μg / mL) and tussah silk fibroin (27. 5 mg / mL) with a volume ratio of 2:1 polyethylene glycol 200 and gelatin solution (360 mg / mL) which accounted for 35% 40% and 25% respectively of the total system. The dissolution loss rate of the BS-TSF-GEL blended film was 34. 62% the elongation at break was 34. 15% and the breaking strength was 578. 8 kPa after being treated with anhydrous ethanol. FTIR and X-ray diffraction results showed that Silk Ⅱ dominated the BS-TSF-GEL blended film while Silk Ⅰ was in a small amount. The BS-TSF-GEL blended film was pale yellow and porous on the surface which was the ideal material for loading antimicrobial peptides. The BS-TSF-GEL blended film loaded with antimicrobial peptides had a good inhibitory effect on both Escherichia coli and Staphylococcus aureus. It is expected to be used in the field of disposable biomedical materials such as wound dressings. In this study three natural materials with unique advantages were selected as substrates for biofilms and polyethylene glycol with high bio-safety was used as the cross-linking agent to enhance the application value of the blended film by loading antimicrobial peptides. The results broaden the application field of silkworm silk and provide a new way for the development and exploitation of silk fibroin in biological dressings and other medical bio-materials. Bombyx mori sericin tussah silk fibroin and gelatin have been widely used in biological tissue engineering as natural biological materials. In this study three natural materials were used as the biofilm substrate to successfully prepare excellent-performance BS-TSF-GEL blend film using polyethylene glycol cross-linking and ethanol post-treatment techniques. Moreover specific properties can be conferred by replacing different loading substances such as antimicrobial biofilm carrying antimicrobial peptides and biofilm sustained release carrier loading drugs. In addition 3D printing electrostatic spinning and other technologies can also be used to shape the BS-TSF-GEL into different shapes to meet the application requirements under different conditions. In conclusion the research results explore a new way for the application of silk protein. © 2022 Authors. All rights reserved.     

Micro-printing performance of durable water-repellent black polyester-spandex fabrics without fluorine and silicone resins北大核心CSCD

Synthetic fibers are widely used because of their stable chemical properties high mechanical strength and low cost. Among them polyester has the largest production and is the most widely used and China is also the country with the largest polyester production in the world. With the technological progress of energy saving and emission reduction of liquid disperse dyes the technology of micro printing of polyester and polyester / spandex fabrics has been realized. Based on the high market share of black polyester / spandex printed fabrics and the increasing market demand for functional finishing (e. g. anti-static finishing water repellent finishing UV resistance finishing etc.), it is of great significance to study the process of one-step short processing of polyester printing and functional finishing using carbon-based materials (e. g. carbon black). Carbon black is a gray-black organic pigment with good antistatic and anti-UV properties. It is an eco-friendly advanced material that integrates printing dyeing and functional finishing. To make up for the lack of color depth of carbon black pigment a disperse black dye and carbon black pigment in the same bath preparation scheme are chosen to prepare a functional liquid carbon black @ disperse black dye (CB-D). Not only does CB-D meet the requirements of deep black printing but also it can simultaneously provide water-repellent finishing to the fabric. In this way the application of organic fluorine or organic silicon resin can be dispensed with. A functional liquid CB-D was prepared by pre-dispersion and zirconium oxide grinding method under the action of abrasive agent AL50 (anionic / non-ionic surfactant complex) . The effects of CB-D mass fraction binder type binder D101 mass fraction baking temperature and time on color (L∗ value) rubbing and soaping colorfastness were investigated by optimizing the printing process of liquid CB-D. At the same time the fixation mechanism of CB-D was investigated and the properties of polyester-spandex printed fabrics were tested. The stability of CB-D and the colorfastness of polyester-spandex printed fabrics to hot-wash effluent were investigated by the rate of change of absorbance. The effect of hot-washing on dye floating in the printed area and dye staining in the non-printed area was characterized by the brightness of the printed area L∗ value and the whiteness of the non-printed area (CIE whiteness W10). The properties of CB-D were characterized by scanning electron microscopy and transmission electron microscopy and the antistatic property water repellency air permeability moisture permeability and tensile breaking strength of the fabrics were tested. (i) The first functional liquid CB-D with excellent stability is prepared by grinding carbon black and disperse black dye composed of orange 288 purple 93 and blue 291:3 in the same bath. (ii) A durable fluorine-free and silicone-free water repellent black polyester spandex fabric is prepared reducing the cost of functional finishing and environmental pollution. The preparation of durable water-repellent polyester spandex fabrics without a functional finishing agent is a new technology. CB-D as functional organic melanin with excellent performance and simple processing is a new low-carbon and eco-friendly material and ecological printing and dyeing process. (i) As for the black polyester spandex fabric prepared by a micro-printing process the color fastness of deep black color is not less than grade 4 the white ground is not stained and the color of wastewater is very low. The printing process requires 5% functional CB-D and 8. 5% binder D101. (ii) The black polyester spandex fabric has excellent and durable water repellency air permeability moisture permeability and antistatic property. The water contact angle is 132° anti-static grade is A and the air permeability and moisture permeability are more than 260 mm / s and 2 880 g / (m2h) respectively. After 30 times of home washing it almost keeps the original excellent performance. (iii) The CB-D prepared based on carbon black and disperse black dye is a colloidal aggregate that easily forms continuous carbon black aggregates on the fiber surface showing more excellent porosity film formation and water repellency while maintaining air permeability and moisture permeability. Carbon black is a low-cost material and the liquid CB-D prepared by modifying carbon black with disperse black dye has a new use in preparing functional textiles with good application prospects. © 2022 Authors. All rights reserved.     

The Role of the American Oil Chemists’ Society in World Trade——Quality Assurance Testing, Certified Reference Materials, and International Liaison Activities (英文原文)(Online First, Recommended Article)

The American Oil Chemists’ Society (AOCS) is a volunteer-led association. AOCS develops and publishes methods of analysis for fats, oils, proteins, surfactants, and related materials according to accepted international standards to ensure equitable trade practices on a global scale. AOCS Official Method development has been going on for over a hundred years. The founding vision of AOCS in 1909 was “an organization designed for the development and advancement of analytical methods for cottonseed products.” AOCS Official Methods are essential to world trade and are used to confirm the value of billions of pounds of oilseed-based commodities and finished products each year. In addition, AOCS conducts proficiency testing, provides certified reference materials, and collaborates with other standards developers including the International Organization for Standardization (ISO) and the Codex Alimentarius Commission. AOCS serves as a professional scientific membership organization providing current and emerging information as well as disseminating research results in oils, fats, lipids, proteins, surfactants, and related materials. Several avenues are used, especially meetings, publications, interest groups, networking opportunities, and web presence. Many scientists, experts, and others engaged in working in these fields find their professional “home” in AOCS. The AOCS Technical Leadership Committee comprises some of the most experienced AOCS members and scientists. The AOCS Technical Services department staff relies on this committee for guidance on scientific matters and for advice in prioritizing the opportunities facing AOCS.     

Occurrence and Antibiotic Susceptibility Profile of Streptococcus spp. Isolated from Ewe＇s Milk

The purpose of this study was to determine the occurrence and antimicrobial resistance of Streptococcus spp. isolated from fresh ewe＇s milk and consequently to draw conclusions concerning the health condition of the animal flocks and the current trends of antibiotic use in small ruminants. A total of 77 mountainous sheepfolds were investigated representing 10% of all transhumant sheep and goats flocks in the area. Duplicate milk samples were collected from January to February transferred to the laboratory and analyzed for the presence of Streptococcus spp. by using the serial dilution method and plating on the surface of Slanetz and Bartley agar. The isolates were tested against nine antimicrobial agents with the Kirby-Bauer disk diffusion method. The results showed that Streptococcus spp. occurred in 84.4% of the samples and in counts ranged between 1.8 log CFU/mL and 4.6 log CFU/mL. Concerning susceptibility, only 1.3% of the isolates were resistant to all antimicrobials while 27.3% were fully susceptible. Resistance to cefepime was the most common （93.1%） observation followed by resistance to ampicillin （82.1%）, ciprofloxacine （58.3%） and meropenem （51.9%）. The isolates were vancomycin susceptible at a rate of 83.6%. Multidrug resistance to at least three antibiotics was observed to be 22.1% of Streptococcus spp.. Given the prevalence of Streptococcus spp. and the elevated resistance of isolates to various antibiotics it is concluded that further examinations and even interventions are required in order to pertain the appropriate animal health and milk quality.