Microbiological plate and turbidimetric assays of chlortetracycline in feeds: collaborative study.

The manual and automated turbidimetric assays and a modified official plate assay for chlortetracycline (CTC-HCl) in feed were collaboratively studied. Three feed samples (swine feed, 100 g CTC-HCl/ton; premix I, 20 g each of CTC-HCl and sulfamethazine/lb, and 10 g penicillin/lb; and premix II, 50 g CTC-HCl/lb) were analyzed at 2 dilutions. Twelve laboratories conducted the plate assay; 8 laboratories the manual turbidimetric method; and 7 laboratories, the Autoturb analysis. Within a method, there was no significant difference between dilutions. Between methods, there was a significant difference between the manual turbidimetric plate assays only for swine feed. However, the same sample dilutions or the average values of the 2 dilutions for both methods showed no statistical difference. Among the collaborators, the slope of CTC-HCl standard curve varied between about 2.0 and 3.0 for the plate method. The turbidimetric assay has been adopted as official first action for feeds containing larger than or equal to 20 g CTC-HCl/lb.     

Sources of variation in hot water extraction and colorimetric determination of soil boron

Abstract

The reliability of the soil test for boron (B) has been questioned in recent years. Two studies were initiated to identify some of the sources of variability in the extraction and analysis phases of the B soil test. The first study evaluated the influence of reflux and cooling times (10,20,30 min.) on B values. The second study investigated the effectiveness of CaCl₂ (0,3,6,9 mM) and charcoal (0,0.08, 0.16, 0.32, 0.64 g) as soil extract decolorizing agents. Hot water extraction, in plastic pouches, with azomethine‐H and/or ICP analysis was used to determine soil B. Increasing reflux time resulted in significantly higher B values, while increasing cooling time resulted in significantly lower B values (P = 0.05). Standardized refluxing/cooling conditions contributed to improved reprodudbility of B values obtained by hot water extraction. Increasing reflux CaCl₂ concentration and/or charcoal addition significantly lowered B values. The lower B values obtained with the CaCl₂ treatments were the direct result of decreased background color. Charcoal was also effective in reducing background color but higher additions of charcoal (greater than 0.16 g) resulted in excessive sorption of boron. Soils should be refluxed in 10 mM CaCl₂ to minimize extract color if azomethine‐H analysis is used. If extract color persists, a minimum addition (less than 0.16 g) of charcoal should be added prior to filtering. The conclusions of this study were incorporated into a soil test B procedure included in this report.     

Pyridine extraction method for determination of bacitracin in feeds: collaborative evaluation.

Seventeen laboratories evaluated the pyridine extraction method and neomycin-sensitized agar for the determination of zinc and MD bacitracin in swine and broiler rations at 10 and 100 g/ton. The method was also applied to the analysis of 2 premixes labeled 50 g/lb (MD bacitracin) and 40 g/lb (zinc bacitracin). Bacitracin activity was determined on each of 2 days with 2 dilutions on each day. No significant difference was found between dilutions within a day or between days for each sample. The type of bacitracin or type of feed did not significantly affect results. The difference in results between MD and zinc bacitracin in premixes approached significance. The large coefficients of variation for premixes (ca 13%) and complete feeds (ca 15--30%) indicate operational problems. The main difficulty was evaporation of pyridine. Some laboratories were not able to evaporate it completely, whereas others lost bacitracin activity, probably due to high temperature of drying. The pyridine extraction method as in 42.200 and 42.204 should be discontinued.     

HPLC Determination of Stability and Distribution of Added Folic Acid and Some Endogenous Folates During Breadmaking

Bread flour was spiked with folic acid (1.40 mg/lb or 3.08 μg/g of flour) and processed into bread by the sponge and dough method. Changes that occurred to added folic acid and endogenous folate contents through different processing stages, including sponge formation, proofing, and baking, were assessed by reversed‐phase ion‐pair HPLC combined with UV and fluorometric detection. Sample extraction required α‐amylase and rat plasma deconjugase digestion, and sample preparation required purification by solid‐phase extraction. Added folic acid was measured by monitoring UV absorption at 280 nm. Four selected forms of endogenous folates including tetrahydrofolate (THF), 5‐formyl‐THF, 10‐formylfolate, and 5‐methyl‐THF were identified and quantified throughout the bread processing using a fluorescence excitation wavelength of 290 nm and emission wavelength of 350 or 450 nm. Data indicate a relatively good stability of added folic acid and native folates to the baking process, and increased endogenous folate contents in dough and bread as compared with the flour from which they were made.     

Natural and induced heavy‐metal accumulation by Arrhenatherum elatius: Implications for phytoremediation

Abstract

The uptake of cobalt, copper, lead, and nickel by the perennial metal‐tolerant grass Arrhenatherum elatius was studied by growing the plants in two different substrates. These were a cobalt/copper/nickel ore (Experiment A) and base‐metal tailings rich in lead (Experiment B). The enhancement of metal uptake by the plants following addition of EDTA was investigated in both experiments. In Experiment A, metal concentrations in dry plant matter were about equal to the acid‐extractable (1 M hydrochloric acid) fractions in the supporting soils after addition of 4 g kg^‐1 EDTA. In Experiment B, the base‐metal tailings contained 11,500 mg kg^‐1 (1.15%) lead. The EDTA addition induced 2.5% lead (dry matter) in the grass. This was reduced to ca. 1.0% upon addition of lime. The results indicate that A. elatius may have some potential in phytoremediation operations if EDTA is added to the substrate.     

Liquid chromatographic determination of L-ascorbic acid in candies and soft drinks

The L-ascorbic acid (AsA) contents of candies and soft drinks available in the market were determined by liquid chromatography (LC). Samples are cleaned up on a disposable Sep-Pak C18 cartridge followed by reverse phase separation on an ODS column using a mobile phase of 0.1% phosphoric acid (pH 2.2). The AsA peak is detected on the basis of the UV absorption at 254 nm. The detection limit was 1 microgram/mL final concentration. Recoveries of AsA added at levels of 1-10 mg/g candy and 1-10 mg/10 mL soft drink were 99.2-101.7% with a coefficient of variation of 0.52-1.20% (n = 5). The present method allows rapid and accurate assays because it is a simple procedure compared with the official dye-titration method, and it is suitable for the routine analysis of AsA in selected candies and soft drinks.     

浙江省重点地区猪粪中重金属含量及安全施用评估

【目的】 浙江的规模养殖集中度高,畜禽排泄物资源化利用率达96%以上,通过堆肥和制作有机肥还田是主要的消纳途径,因此粪便中的重金属含量影响土壤安全及作物的生长。饲料是猪粪重金属最主要的来源,因此,本研究检测了浙江省猪饲料和排泄物中的重金属,为作物施用的安全性评价提供基础数据。 【方法】 采集35家不同规模养殖场的仔猪、生长猪和育肥猪3个阶段饲喂的饲料和粪便样本共566个,采用干灰化法、高压消解法消解,用AAS、AFS、ICP-MS法分析了铁、铜、锰、锌、砷、铅、铬、镉和汞9种重金属含量。 【结果】 1) 粪便中8种重金属平均含量趋势为Zn > Cu > Mn > As > Cr > Pb > Cd > Hg,主要残留元素为Zn、Cu、Mn和As,按干物质计其平均值分别为2405、1288、528和28.2 mg/kg,变异系数 ( CV) 分别为83%、34%、6%和15%。猪粪中Cr、Pb、Cd元素含量较低,在0.29～3.52 mg/kg之间,Hg含量仅3.97 μg/kg。猪粪中重金属含量仔猪阶段趋高,育肥猪阶段趋低,各个阶段变异都较大,变异系数CV值介于21%～112%之间,显示各地的生猪饲养中微量元素添加还比较混乱。2) 饲料有机砷的使用存在明显区域差异,萧山地区占72.7%的饲料样本在各阶段猪饲料中均添加有机砷,衢州地区的占33.3%,两个地区各有1家养殖场未使用有机砷。猪粪中54.9%样本砷含量 > 15 mg/kg,16.9%样本砷含量 > 50 mg/kg,2.8%的粪便砷超过70 mg/kg。3) 按畜禽粪便安全使用准则进行判定,69.9%猪粪铜超标,16.9%猪粪砷超标。按有机肥料标准进行判定,猪粪中54.9%样本砷含量超标。按照饲料中金属元素在粪便中的浓缩率:Fe、Zn、Cu为7～10倍,锰约为3倍,当前饲养水平下,Fe、Zn、Cu元素存在过量添加。4) 以浙江全省旱地单位面积承载量估算,当前能消纳猪粪中Zn、Cu的排放,但当每公顷猪粪施用量超过2.27 t (干计) 时,局部地区重金属就有累积风险。 【结论】 应降低猪饲料中微量元素的添加量,禁止饲用有机砷制剂,才能有效降低猪粪施用所导致的重金属污染;按照目前监测猪粪肥重金属元素含量水平,有机肥的施用量用应控制在2.27 t/hm2 (干基) 以内,以防止对土壤造成污染。      

Deoxynivalenol and zearalenone residues in eggs of laying hens fed with a naturally contaminated diet: effects on egg production and estimation of transmission rates from feed to eggs

The potential for the Fusarium mycotoxins 4-deoxynivalenol (DON) and zearalenone (ZON) to enter the human food chain through contaminated eggs was assessed using a controlled feed study. Four groups of laying hens (eight in each group) were fed a diet that included differing amounts of naturally contaminated wheat containing DON ( approximately 20 mg kg(-1)) and ZON (0.5 mg kg(-1)). Eggs were collected and pooled from each group on a daily basis. Pooled samples were analyzed by liquid chromatography with mass spectrometry detection (LC-MS/MS). The method allowed DON, other type B trichothecenes, ZON, and its metabolites to be determined in a single multi-residue analysis. The selectivity of the MS/MS procedure allowed cleanup to be minimized (for DON, cleanup by immunoaffinity column was used) or eliminated (for ZON). The limits of detection of 0.01 microg kg(-1) for DON and 0.1 microg kg(-1) for ZON in eggs were lower than previously published methods. None of the samples analyzed had detectable levels of ZON or its metabolites. Although maximum levels of DON contamination (10 mg kg(-1) feed) were relatively high, no adverse effects were observed on egg production. On the basis of the determined DON levels in the hen's diet and the determined levels of DON in the corresponding eggs, transmission rates of 15 000:1, 18 000:1, and 29 000:1 for treatment levels 5, 7.5, and 10 mg DON kg(-1) feed, respectively, were found. These results show that, although eggs could be a human exposure route for DON, the levels are insignificant compared to the other sources, although the presence of metabolites of DON was not studied.     

硫酸铵与鸡粪配比在含生物质炭育苗基质中的应用效果

研究了基质中添加生物质炭(5％)及在含生物质炭基质中进行硫酸铵(0.5g/L,0.75 g/L,1 g/L)与鸡粪(5％,10％,15％)配比对基质理化性质和番茄幼苗生长发育的影响.研究结果表明,(1)基质中添加生物质炭后除pH值升高外其他理化性质明显改善,而且0.5 g/L的硫酸铵添加量可以显著降低基质pH值(P＜0.05);(2)硫酸铵与鸡粪配比,硫酸铵可以降低基质pH值、增加EC值,而鸡粪使基质的理化特性指标均呈增加趋势;(3)从番茄幼苗健壮状况看,首先,生物质炭可以明显促进番茄幼苗的生长发育.其次,硫酸铵和鸡粪配比后番茄幼苗的健壮程度与基质养分含量及EC值变化规律呈负相关.研究结果说明,基质中添加生物质炭后,硫酸铵和鸡粪含量同时最低的配比处理对番茄幼苗的生长发育促进效果最明显,叶面积、株高、茎粗、地上生物量、地下生物量及壮苗指数等值均最大,可以满足番茄育苗要求.     

Lipid stability and antioxidant profile of microsomal fraction of broiler meat enriched with α-lipoic acid and α-tocopherol acetate

The importance of the linkage between nutrition and health is a hot issue. Like other food-related sectors, the meat industry is undergoing foremost transformations, driven among other things by changes in consumer requirements. The present study was designed to evaluate the lipid stability and antioxidative potential of leg and breast microsomal fraction of broiler meat fed on ALA and ATA. For the first 3 weeks of growth, broilers were fed on feed supplemented with ATA (200 mg/kg of feed) and during the last 3 weeks broilers were fed on feed supplemented with ALA (25, 75, 150 mg/kg of feed) and a constant level of ATA (200 mg/kg of feed). The body weight of the carcass was measured after every week of growth until 6 weeks. Positive correlation between the antioxidant activity and the TPC was observed. Higher values of TBARS were detected in leg muscles than in breast muscles. HPLC data revealed ALA and ATA contents were higher in T(4) (leg, 5.55 ± 0.19 and 3.87 ± 0.15 μg/mg of protein; breast, 5.63 ± 0.20 and 2.03 ± 0.10 μg/mg of protein, respectively) and lowest in T(5) (ALA, leg, 1.40 ± 0.06 μg/mg of protein; breast, 1.54 ± 0.05 μg/mg of protein; ATA, leg, 1.25 ± 0.06 μg/mg of protein; breast, 0.63 ± 0.008 μg/mg of protein), in which the only oxidized oil was used. Oxidized oil in feed reduced weight gain and increased TBARS, whereas TPC, DPPH, ALA, and ATA values decreased in both leg and breast meat.     

Liquid chromatographic determination of narasin in feed premixes

A liquid chromatographic (LC) method has been developed to determine narasin in feed premixes. Narasin is extracted from the premix with a methanol-water solvent, and the extracted solution is assayed by using LC. Recovery of narasin from a 12.5 g/lb premix is quantitative (100%), with a relative standard deviation of 1.44%. The results correlated well (coefficient 0.92) with a turbimetric bioassay method.     

Monoclonal antibody-based enzyme linked immunosorbent assay of aflatoxin B1, T-2 toxin, and ochratoxin A in barley

Aflatoxin B1 (B1), T-2 toxin (T2), and ochratoxin A (OA) were assayed in a single extract from barley grain by using competitive enzyme linked immunosorbent assays (ELISAs) with monoclonal antibodies. B1 and T2 monoclonal antibodies were conjugated to horseradish peroxidase for direct competitive ELISA while an indirect competitive ELISA was used for OA determination. The competitive ELISA detected 0.1 ng/mL of B1, 10 ng/mL of T2, or 1 ng/mL of OA. Acetonitrile-0.5% KCl-6% H2SO4 (89 + 10 + 1) extracts of barley grain either were diluted 1:10 for direct assay or were subjected to a simple liquid-liquid cleanup procedure to concentrate the extract 10:1 before assay. For cleanup, water was added to the acetonitrile extract to partition water-soluble interfering substances, and then the mycotoxins were re-extracted with chloroform. The chloroform extract was evaporated to dryness and redissolved in Tris HCl buffer for ELISA. The mean recoveries from barley spiked with 4-60 ng/g of B1, 50-5000 ng/g of T2, and 5-500 ng/g of OA were, respectively, 93.8, 80.6, and 95.8%. The mean within-assay, inter-assay, and subsample coefficients of variation by ELISA of barley grain colonized with toxigenic fungi were less than 12% for B1 and OA but as high as 17% for T2.     

山西小麦主产区土壤中钴含量状况及影响因素研究

试验分析研究了山西省小麦主产区之一——运城市土壤中钴的含量状况及其影响因素。研究结果表明。运城市4县区土壤全钴含量为1.65～17．85mg／kg，平均6．00mg／kg，略高于缺钴临界值5．0mg／kg，而低于全国平均值11．2mg／kg;土壤有效钴含量为0．060～2．235mg／kg,平均0．694mg／kg。在34个土样中，大约有60％的样品有效钴含量低于均值．而含量高于均值的土样仅占总样品数的40％。试验区主要土类褐土和潮土全钴含量分别为6．17mg／kg和4．73mg／kg，有效钴含量分别为0．708mg／kg和0．589mg／kg。影响土壤中全钴含量的因素主要是成土母质、成土过程和铁锰含量，影响有效钴含量的因素主要是成土母质、成土过程和有机质。     

水稻秸秆降解复合菌系的筛选构建及其田间应用效果

  【目的】  筛选并构建适宜原位还田水稻秸秆快速腐解的高效多功能复合菌系,以提高秸秆原位还田的腐解速率。  【方法】  秸秆原位腐解菌株从水稻田带有腐烂秸秆的表层土壤中筛选分离,分别采用DNS法、摇瓶培养观察法和失重法测定了腐解菌株的羧甲基纤维素酶活性、滤纸崩解能力及水稻秸秆降解能力,对降解效果较好的菌株进行了16S rRNA或18S rRNA鉴定。选取无拮抗作用的菌株构建复合菌系,并在实验室条件下测定各复合菌系的滤纸酶活性和秸秆降解率。挑选降解效果较好的复合菌系进行田间试验,分析了秸秆降解率、土壤有机质及速效养分含量,调查了水稻产量。  【结果】  从土壤中共分离到秸秆降解率均高于19.8%的菌株有6个,包括B2、B5、B6、F1、F5、F12,经鉴定分别为贝莱斯芽孢杆菌(Bacillus velezensis,B2)、耐盐芽孢杆菌(Bacillus halotolerans,B5)、枯草芽孢杆菌(Bacillus subtilis,B6)、米曲霉(Aspergillus oryzae,F1)、黑曲霉(Aspergillus niger,F5)、长枝木霉(Trichoderma longibrachiatum,F12),其中F12 (长枝木霉)的秸秆降解率最高(29.1%)。以该6个菌株构建了7组复合菌系,复合菌系B2+F12、F1+F5+F12、B2+F5+F12的秸秆降解效果较好,在液体培养基中,对秸秆的降解率分别达到32.9%、29.8%、40.3%。利用这3组复合菌系进行田间试验,结果表明,复合菌系B2+F5+F12表现最好,与未施菌剂相比,原位还田的水稻秸秆降解率提高了37.1个百分点,土壤有机质、碱解氮、速效磷、速效钾含量分别增加了2.1 g/kg、1.9 mg/kg、0.6 mg/kg、1.7 mg/kg,水稻产量提高了6.3% (P<0.05)。  【结论】  施用复合菌系B2+F5+F12不仅具有良好的水稻秸秆降解能力,同时能增加土壤有机质、碱解氮、速效磷、速效钾含量,并促进作物产量的提高,具有较好的应用潜力。     

Enzyme-linked immunosorbent assay for screening aflatoxin B1 in cottonseed products and mixed feed: collaborative study

A joint AOAC/IUPAC (International Union of Pure and Applied Chemistry) interlaboratory study of an enzyme-linked immunosorbent screening assay (ELISA) for aflatoxins was conducted in laboratories in Canada, France, Japan, South Africa, Switzerland, The Netherlands, Tunisia, and the United States. Twenty-eight samples of raw and roasted peanuts, corn, whole cottonseed, cottonseed meal, ammoniated cottonseed meal, and poultry feed containing various quantities of natural aflatoxins and supplemented when appropriate with aflatoxin B1 were distributed to participating laboratories for testing. The assay is based on conjugation of pure aflatoxin B1 to an enzyme and the competition between this conjugate and (free) aflatoxins in the product for aflatoxin-specific antibodies coated onto microtiter well walls. After a wash step to remove all unbound aflatoxins, a substrate, added to each well, is catalyzed from a colorless to a green solution by any bound enzyme-conjugated aflatoxin B1 present. The intensity of the color decreases as the amount of free aflatoxin B1 in the product increases. Overall correlation was good between ELISA and thin-layer chromatographic (TLC) results for cottonseed products and mixed feed. Variable results were reported for corn and peanut product samples. Although some positive samples (greater than 15 ng/g) of cottonseed products and mixed feed were reported to contain less than 15 ng/g by visual determination, a review of data for absorbance measurements showed that the contamination level was close to the greater than or equal to 15 ng/g standard and would not have been reported as negative under routine screening.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of extraction procedures on determination of critical soil and foliar levels of boron and zinc in coffee plants

Abstract

Six‐month‐old coffee plants were grown in the greenhouse in pots containing a Dark Red Latosol (Orthox), to study the effect of boron (B) and zinc (Zn) on growth and leaf content of these micronutrients. Boron was added at levels of 0, 1, 3, and 5 mg kg^‐1, whereas Zn was added in proportions of 0, 5, 10, and 20 mg kg^‐1. Boron application affected total dry matter, height and diameter of stem, length and number of plagiotropic branches, number of leaves, ratio between total leaf area and number of leaves (ULA), ratio between total leaf area and total dry matter (LAR), leaf moisture, and index of potential yield (IPY). The IPY, defined as the ratio of dry matter of developed flowering buds plus flowers to the dry matter of underdeveloped flower buds and flowers, proved to be the an excellent parameter to assess B levels. Leaf B, well correlated with IPY, varied from 50 to 60 mg kg^‐1. Available B in soils, in nig kg^‐1, ranged from (with the critical levels between parentheses): 0.2 to 0.3 (0.2), as determined in a saturation paste, 0.6 to 1.0 (0.9), as determined in a hot water extract, 0.9 to 1.3 (1.2), with monocalcium phosphate in acetic acid, 1.1 to 1.4 (1.3), by Mehlich 1 method, 2.1 to 2.4 (2.4), by 0.05N HC1, 2.2 to 2.4 (2.4), by 0.1N HCl. Zinc additions caused a decrease in growth when B supply was limiting. On the other hand, B had no effect on dry matter yield when Zn was not added. Adequate Zn soil levels in mg kg^‐1 were 4.4, as determined by 0.05N HCl extraction, 4.2, by 0.1N HC1, 3.9, by Mehlich 1, 2.7, by EDTA extraction, and 2.1, in DTPA extracts. Leaf Zn, not affected by Zn additions, was between 12–14 mg kg^‐1.     

Development and validation of a lateral flow device for the detection of nicarbazin contamination in poultry feeds

Concentrations of the coccidiostat nicarbazin as low as 2 mg/kg in feed can result in violative drug residues arising in poultry liver. A lateral flow device (LFD) was developed for the detection of contaminating concentrations of nicarbazin following solvent extraction of poultry feeds. Test results, as determined by both visual and instrumental measurement, are available within minutes. For 22 feed samples, nicarbazin-free and fortified at 2 mg/kg, the % relative inhibition ranged from 0 to 45% and from 53 to 85%, respectively. Nicarbazin contamination at the critical concentration (2 mg/kg) can be determined in all cases providing the sampling is representative. A wide range of feed samples taken at a mill that incorporated nicarbazin into poultry feed were analyzed. Data generated for these samples by both the LFDs and a mass spectrometric method were compared, and a significant correlation was achieved.     

Liquid chromatographic determination of morphine sulfate and some contaminants in injections and bulk drug material

A liquid chromatographic (LC) procedure is described for the assay of morphine sulfate in bulk drug material and injection solutions. The bulk drug and injection samples are prepared by direct dilution with LC mobile solvent. The average bulk drug purity (5 manufacturers) determined by the LC method was 99.9% with a difference of 0.1% from the average purity (anhydrous) found by the official USP XX procedure. The average LC recovery (19 studies) of morphine sulfate added to injection samples was 99.4% with a coefficient of variation (CV) of 1.14%. Morphine sulfate content was determined in triplicate for 53 injection samples (1-15 mg morphine sulfate/mL) formulated by 6 manufacturers, using the proposed LC procedure. Individual sample CV (n = 3) averaged 1.14%. The LC method is simple and specific for morphine sulfate. Major degradation products, preservatives, and some contaminants and related compounds are separated during LC.     

Potassium fertilizer recommendations and changes in potassium soil test values as influenced by additions of potassium

Abstract

The A and B horizons of 28 Delaware soils were incubated with 0, 200, 1000 and 2000 ug K/g of soil for one week, one, two and six months. Potassium soil test values were determined using the double acid extractant. The amount of K necessary to raise the soil test value one unit varied between five and 12 ug K/g of soil and was influenced by time of incubation, soil type, amount of K added and soil horizon. Correlation coefficients between the units of K necessary to raise the soil test values one unit and sand, silt and clay and cation exchange capacity are presented. Increasing soil test values to some predetermined point does not appear agronomically or economically sound for the Coastal plain soils of Delaware. Using this procedure to determine fertilizer K recommendations results in recommendations several fold higher than those recommendations which result from using field crop response to determine the amount of K fertilizer to be applied.     

适宜电子束辐照延长醉泥螺货架期及蛋白质保持

为探明电子束辐照对醉泥螺的杀菌效果及辐照后醉泥螺感官品质与蛋白质营养价值的变化,为生食醉泥螺的辐照保鲜应用提供理论依据。以生食醉泥螺为研究材料,研究不同剂量电子束辐照对醉泥螺菌落总数、感官评分、蛋白质含量及其氨基酸组成的影响,并分析辐照后醉泥螺在冷藏和常温贮藏条件下的货架期变化。结果表明：1）经1～9 kGy剂量电子束辐照,醉泥螺的色泽和形态几乎没有变化,但7、9 kGy剂量组醉泥螺产生异味;2）辐照剂量越高,杀菌效果越好,当醉泥螺的初始菌落总数为1200 cfu/g时,菌落总数降至初始值10%所需的辐照剂量D10为3.46 kGy;3和5 kGy剂量的辐照对醉泥螺的抑菌效果明显,无论是冷藏还是常温贮藏,360 d内菌落总数均未超过5000 cfu/g;3）辐照对醉泥螺蛋白质含量无明显影响(P?0.05),不改变醉泥螺的限制性氨基酸种类,但经1、3、5 kGy辐照后,氨基酸总量、必需氨基酸总量及各必需氨基酸的氨基酸评分增加;4）结合电子束辐照对醉泥螺菌落总数及感官评分的影响,辐照剂量以3 kGy为宜,醉泥螺保质期冷藏条件下由对照组的5个月延长至12个月,常温条件下由对照组的不到1个月延长到3个月。该结果能为电子束辐照保鲜醉泥螺提供依据。