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1.
Ovomucin glycopeptide (OGP) was prepared by size exclusion chromatography after Pronase digestion of hen egg ovomucin, and the binding of OGP to foodborne pathogens (Bacillus cereus,Clostridium perfringens, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enteritidis, Salmonella typhimurium, and Staphylococcus aureus) was investigaed. Binding assays with biotinylated bacteria as probes in microtiter plates showed that OGP bound to only E. coli O157:H7 among these foodborne pathogens. Periodate treatment markedly reduced the binding ability, indicating that E. coli O157:H7 bound to carbohydrate moieties of OGP. Lectin blot analysis with Maackia amurensis (MAA) and Sambucus nigra (SNA), which are specific for oligosaccharides containing sialic acid, revealed their binding sites in OGP were similar to the E. coli O157:H7 binding sites that were probed with biotinylated E. coli O157:H7 after Western blotting of OGP. Sialydase treatment of OGP abolished its ability to bind E. coli O157:H7, demonstrating that sialic acid played an important role in the binding. These results suggest that OGP has E. coli O157:H7-specific binding sites that consist of sialic acid. On the basis of these properties, OGP has the potential to be an ingredient with a protective effect against E. coli O157:H7 infection and to be a novel probe for the detection of E. coli O157:H7 in the food hygiene field.  相似文献   

2.
Meats need to be heated to inactivate foodborne pathogens such as Escherichia coli O157:H7. High-temperature treatment used to prepare well-done meats increases the formation of carcinogenic heterocyclic amines (HCAs). We evaluated the ability of plant extracts, spices, and essential oils to simultaneously inactivate E. coli O157:H7 and suppress HCA formation in heated hamburger patties. Ground beef with added antimicrobials was inoculated with E. coli O157:H7 (10(7) CFU/g). Patties were cooked to reach 45 °C at the geometric center, flipped, and cooked for 5 min. Samples were then taken for microbiological and mass spectrometry analysis of HCAs. Some compounds were inhibitory only against E. coli or HCA formation, while some others inhibited both. Addition of 5% olive or apple skin extracts reduced E. coli O157:H7 populations to below the detection limit and by 1.6 log CFU/g, respectively. Similarly, 1% lemongrass oil reduced E. coli O157:H7 to below detection limits, while clove bud oil reduced the pathogen by 1.6 log CFU/g. The major heterocyclic amines 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were concurrently reduced with the addition of olive extract by 79.5% and 84.3% and with apple extract by 76.1% and 82.1%, respectively. Similar results were observed with clove bud oil: MeIQx and PhIP were reduced by 35% and 52.1%, respectively. Addition of onion powder decreased formation of PhIP by 94.3%. These results suggest that edible natural plant compounds have the potential to prevent foodborne infections as well as carcinogenesis in humans consuming heat-processed meat products.  相似文献   

3.
The molecular motion of water was studied in glucono-δ-lactone-acidified skim milk powder (SMP) solutions with various pH values and dry matter contents. NMR relaxometry measurements revealed that lowering the pH in SMP solutions affected 17O and 1H T2 relaxation rates almost identically. Consequently, the present study indicates that the proteins present in the samples do not affect the 1H relaxation behavior markedly, even at relatively high SMP concentrations (15-25%). Comparison of rheological measurements and NMR measurements suggested that the collapse of κ-casein during acidification could contribute to the initial decrease in 17O and 1H relaxation rate in the pH range between 6.6 and 5.5 for 15% SMP and in the pH range between 6.6 and 5.9 for 25% SMP. However, below pH 5.5 the viscosity and 17O and 1H NMR relaxation rates did not correlate, revealing that the aggregation of casein micelles, which increases viscosity below pH 5.5, does not involve major repartitioning of water.  相似文献   

4.
Water characteristics and meat microstructure of NaHCO3-enhanced pork were compared with NaCl- and Na4O7P2-enhanced pork using low-field proton NMR relaxometry, advanced microscopy techniques, and traditional meat quality measurements. Porcine samples were enhanced at 4 degrees C for 48 h with sodium salts individually and in the following combinations: (i) 5% NaCl, (ii) 5% Na4O7P2, (iii) 3% NaHCO3, (iv) 5% NaCl and 5% Na4O7P2, (v) 5% NaCl and 3% NaHCO3, (vi) 5% Na4O7P2 and 3% NaHCO3, and (vii) 5% NaCl, 5% Na4O7P2, and 3% NaHCO3. Independently of the marinade used, the water-binding capacity was improved, cooking loss was reduced, and the yield was enhanced compared with nonmarinated pork samples. This was also reflected in the water mobility within the samples measured by proton NMR relaxometry. Visualization of samples by confocal laser scanning microscopy (CLSM) revealed salt-dependent microstructural changes in the green pork samples treated with NaHCO3, giving rise to nearly complete disintegration of overall structures. High-resolution visualization by atomic force microscopy (AFM) further suggested that a higher cooking loss in sodium chloride-enhanced samples could be ascribed to less solubilization and higher heat-induced protein denaturation compared with phosphate- and bicarbonate-enhanced samples.  相似文献   

5.
All eight C6-aliphatic alcohol and aldehyde compounds in naturally occurring green leaves showed bacteriostatic effects against Staphylococcus aureus IFO 12732, methicillin-resistant S. aureus, Escherichia coli IFO 3301, E. coli O157:H7, and Salmonella enteritidis, with bacteriostatic activities of less than 12.5 microg mL(-1). In this study, the susceptibility of Gram-positive bacteria tested was observed to be greater than that of Gram-negative bacteria. The bactericidal action of the aldehyde compounds was found to be much stronger than that of the alcohol compounds under both liquid and gaseous conditions. The most effective compound was (3E)-hexenal at concentrations of 0.1 and 1 microg mL(-1), which killed 2.1 x 10(5) cfu mL(-1) of S. aureus IFO 12732 and 1.4 x 10(5) cfu mL(-1) of E. coli IFO 3301, respectively, by direct contact with the compound. Lethality of (3E)-hexenal against S. aureus IFO 12732 and E. coli IFO 3301 was also observed as a result of gaseous contact at concentrations of 3 and 30 microg mL(-1), respectively. The bactericidal effects of 30 microg mL(-1) (3E)-hexenal were thoroughly maintained throughout periods of 2 days and 1 day against S. aureus IFO 12732 and E. coli IFO 3301, respectively, by a complex formation with alpha-cyclodextrin.  相似文献   

6.
Chemical compositions and inhibitory effects of essential oils of Turkish oregano (Origanum minutiflorum O. Schwarz & P. H. Davis), bay laurel (Laurus nobilis L.), Spanish lavender (Lavandula stoechas subsp. stoechas L.), and fennel (Foeniculum vulgare Mill.) on Escherichia coli O157:H7, Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus were determined. After the essential oils were applied on the foodborne pathogens at doses of 0 (control), 5, 10, 20, 30, 40, 50, and 80 microL/mL, the resultant numbers of cells surviving were counted. Results revealed that all essential oils exhibited a very strong antibacterial activity against the tested bacteria (P < 0.05). Gas chromatography-mass spectrophotometry analyses revealed that carvacrol (68.23%), 1,8-cineole (60.72%), fenchone (55.79%), and trans-anethole (85.63%) were the predominant constituents in Turkish oregano, bay laurel, Spanish lavender, and fennel essential oils, respectively.  相似文献   

7.
Mobility and distribution of water in cassava (rainy and drought crops) and potato starches were studied by solid state and NMR relaxometry as a function of H(2)O and D(2)O contents ranging from 0 to 44% (dry basis). Measurements of relative mobility derived from (2)H solid state NMR were based on relative area and line shape analysis. The narrow peak (mobile component) started to show at 5% and increased with increasing D(2)O content. This increase in mobile fraction was accompanied by a line narrowing. The mobile fractions of deuterons reached a >98% level above 15% D(2)O, which is well below the water holding capacity of starch ( approximately 27%) and the previously assigned "glassy-rubbery transition point" (24.3%; Jouppila, K.; Roos, Y. H. The physical state of amorphous corn starch and its impact on crystallization. Carbohydr. Polym. 1997, 32, 95-104). This reconfirms the liquidlike nature of water in the so-called glassy state of starch granules. The plasticization effect of water on starch chains was observed at 14-17% for cassava and potato starches as indicated by the T(1) minimum. This, however, did not seem to relate to the difference observed in swelling among the starches studied.  相似文献   

8.
Milk protein-based edible films containing 1.0% (w/v) oregano, 1.0% (w/v) pimento, or 1.0% oregano-pimento (1:1) essential oils mix were applied on beef muscle slices to control the growth of pathogenic bacteria and increase the shelf life during storage at 4 degrees C. Meat and film were periodically tested during 7 days for microbial and biochemical analysis. The lipid oxidation potential of meat was evaluated by the determination of thiobarbituric reactive substances (TBARS). The availability of phenolic compounds from essential oils was evaluated by the determination of total phenolic compounds present in the films during storage. Antioxidant properties of films during storage were also evaluated following a modified procedure of the N,N-diethyl-p-phenylenediamine colorimetric method. Oregano-based films stabilized lipid oxidation in beef muscle samples, whereas pimento-based films presented the highest antioxidant activity. The application of bioactive films on meat surfaces containing 10(3) colony-forming units/cm2 of Escherichia coli O157:H7 or Pseudomonas spp. showed that film containing oregano was the most effective against both bacteria, whereas film containing pimento oils seems to be the least effective against these two bacteria. A 0.95 log reduction of Pseudomonas spp. level, as compared to samples without film, was observed at the end of storage in the presence of films containing oregano extracts. A 1.12 log reduction of E. coli O157:H7 level was noted in samples coated with oregano-based films.  相似文献   

9.
Abstract. Slurry from farm animals may contaminate water supplies, rivers and bathing waters with faecal coliforms, such as Escherichia coli . Where animals harbour the O157 strain the hazard to human health is particularly high, but both the hazard level, and the low incidence and sporadic nature of the excretion of E. coli O157 make it difficult to study this strain under field conditions. The survival of total E. coli and of E. coli O157 were compared in the laboratory for two soils under controlled temperature and moisture. E. coli O157 die-off rate was the same as or quicker than for total E. coli . This result meant that field experiments studying the fate of total E. coli should give a satisfactory evaluation of the risk of water contamination by the O157 strain. In four field experiments at three sites, slurry containing total E. coli numbers of 2.2 × 104 to 5.7 × 105 colony forming units per mL (c.f.u. mL–1) was applied to drained field plots. Field die-off was faster than expected from laboratory experiments, especially in one experiment where two weeks dry weather followed application. In all but this experiment, the first drain flow events after slurry application led to very high E. coli concentrations in the drains (103 to 104 c.f.u. mL–1). E. coli O157 was present in the slurry used for two of the experiments (33 c.f.u. per 100 mL in each case). However the proportion of E.coli O157 was very low (about 1 in 105) and it was not detected in the drainage water. After the first week E. coli drainage water numbers decreased rapidly but they were 1–10 c.f.u. mL–1 for much of the sampling period after slurry application (1–3 months).  相似文献   

10.
Major active compounds from essential oils are well-known to possess antimicrobial activity against both pathogen and spoilage microorganisms. The aim of this work was to determine the alteration of the membrane fatty acid profile as an adaptive mechanism of the cells in the presence of a sublethal concentration of antimicrobial compound in response to a stress condition. Methanolic solutions of thymol, carvacrol, limonene, cinnamaldehyde, and eugenol were added into growth media of Escherichia coli O157:H7, Salmonella enterica serovar typhimurium, Pseudomonas fluorescens, Brochothrix thermosphacta, and Staphylococcus aureus strains. Fatty acid extraction and gas chromatographic analysis were performed to assess changes in membrane fatty acid composition. Substantial changes were observed on the long chain unsaturated fatty acids when the E. coli and Salmonella strains grew in the presence of limonene and cinnamaldehyde and carvacrol and eugenol, respectively. All compounds influenced the fatty acid profile of B. thermosphacta, while Pseudomonas and S. aureus strains did not show substantial changes in their fatty acid compositions.  相似文献   

11.
Escherichia coli O157:H7 has an unusually high resistance to acidic environments. Some research has revealed that acid-adapted cells, by exposure to moderately acidic conditions, are more resistant to a subsequent strong acidic challenge or other stress. This study was conducted to understand the protein expression regulation of acid tolerance response (ATR) of a local isolated E. coli O157:H7 TWC01 (TWC01) induced by an acidic environment. TWC01 cells were acid adapted by using hydrochloric acid (HCl) or lactic acid as acidifier to induce ATR. The total proteins of adapted cells were extracted for proteomic analysis and protein identification by matrix-assisted laser desorption ionization quadrupole time-of-flight tandem mass spectrometry (MALDI-Q-TOF MS/MS). Furthermore, the effects of acid adaptation on shiga-like toxin (stx) secretion were examined. Results revealed that acid adaptation depressed stx production of E. coli O157:H7 TWC01 during adaptation and did not improve post-stress toxin production. Image analysis of the gel indicated that numerous proteins were up-regulated and that lactic acid had a greater effect than HCl did (percentages of up-regulated proteins were 57.64 and 35.47%, respectively). Analysis of proteins by mass spectrometry revealed that most of the up-regulated proteins were metabolism-related, including phosphoglycerate kinase (PGK), glutamate decarboxylases alpha and beta (GadA, GadB), adenine phosphoribosyltransferase (APRT), and dihydrodipicolinate synthase (DHDPS). Others were related to translation (e.g., elongation factor Tu, elongation factor G), protein folding (e.g., alkyl hydroperoxide reductase), and membrane proteins (e.g., ompA precursor and ompR). The variation of protein expression showed that acid resistance was induced in TWC01 and was primarily manifested via expression of up-regulated proteins that contribute to increased energy conservation and polypeptide synthesis.  相似文献   

12.
1H NMR relaxometry is used in earth science as a non‐destructive and time‐saving method to determine pore size distributions (PSD) in porous media with pore sizes ranging from nm to mm. This is a broader range than generally reported for results from X‐ray computed tomography (X‐ray CT) scanning, which is a slower method. For successful application of 1H NMR relaxometry in soil science, it is necessary to compare PSD results with those determined from conventional methods. The PSD of six disturbed soil samples with various textures and soil organic matter (SOM) content were determined by conventional soil water retention at matric potentials between −3 and −390 kPa (pF 1.5–3.6). These PSD were compared with those estimated from transverse relaxation time (T2) distributions of water in soil samples at pF 1.5 using two different approaches. In the first, pore sizes were estimated using a mean surface relaxivity of each soil sample determined from the specific surface area. In the second and new approach, two surface relaxivities for each soil sample, determined from the T2 distributions of the soil samples at different matric potentials, were used. The T2 distributions of water in the samples changed with increasing soil matric potential and consisted of two peaks at pF 1.5 and one at pF 3.6. The shape of the T2 distributions at pF 1.5 was strongly affected by soil texture and SOM content (R2 = 0.51 − 0.95). The second approach (R2 = 0.98) resulted in good consistency between PSD, determined by soil water retention, and 1H NMR relaxometry, whereas the first approach resulted in poor consistency. Pore sizes calculated from the NMR data ranged from 100 μm to 10 nm. Therefore, the new approach allows 1H NMR relaxometry to be applied for the determination of PSD in soil samples and for studying swelling of SOM and clay and its effects on pore size in a fast and non‐destructive way. This is not, or only partly, possible by conventional soil water retention or X‐ray CT.  相似文献   

13.
Edible films, as carriers of antimicrobial compounds, constitute an approach for incorporating plant essential oils (EOs) onto fresh-cut fruit surfaces. The effect against Escherichia coli O157:H7 of oregano, cinnamon, and lemongrass oils in apple puree film-forming solution (APFFS) and in an edible film made from the apple puree solution (APEF) was investigated along with the mechanical and physical properties of the films. Bactericidal activities of APFFS, expressed as BA50 values (BA50 values are defined as the percentage of antimicrobial that killed 50% of the bacteria under the test conditions) ranged from 0.019% for oregano oil to 0.094% for cinnamon oil. Oregano oil in the apple puree and in the film was highly effective against E. coli O157:H7. The data show that (a) the order of antimicrobial activities was oregano oil > lemongrass oil > cinnamon oil and (b) addition of the essential oils into film-forming solution decreased water vapor permeability and increased oxygen permeability, but did not significantly alter the tensile properties of the films. These results show that plant-derived essential oils can be used to prepare apple-based antimicrobial edible films for various food applications.  相似文献   

14.
Abstract. Escherichia coli serotype O157 is a virulent human pathogen the global incidence of which has increased. It has been demonstrated that cattle are the primary reservoir of this pathogen. This has serious implications for the land-based disposal of organic wastes such as cattle manure, cattle slurry and abattoir waste. Further, it also has serious ramifications for the protection of surface and groundwater drinking supplies and public access to pasture land. However, while soil and vegetation can be expected to directly influence the survival of this pathogen, there is a paucity of information concerning the behaviour and survival of E. coli O157 in agricultural environments. It appears that E. coli O157 presently contaminates between 1 to 15% of UK cattle herds, depending on region, and that faecal excretion of the bacterium shows a distinct seasonality which also reflects the incidence of human infections. E. coli O157 can remain viable in soil for greater than 4 months and appears to be a highly resilient pathogen possessing the capability to adapt easily to environmental stresses. While most human cases of E. coli O157 related food poisoning have been associated with the consumption of contaminated meat and dairy products, there is also evidence that human infection has occurred through the ingestion of contaminated soil, fruit and vegetables and drinking water. In this review the potential threat to human health posed by the application of contaminated organic wastes to soil and possible strategies for reducing the amount of pathogen entering the food chain are highlighted.  相似文献   

15.
Recently, there has been a surge of interest in understanding the survival of Shiga toxin-producing Escherichia coli (STEC) in aquatic environments. Fifteen strains of STEC were monitored, individually, in untreated well water samples incubated at 10 and 22^C for 56 days. The strains were selected from three serogroups (O26, Ol11 and O157) and represented five distinct ERIC (enterobacterial repetitive intergenic concensus)-genotypes. The microcosms were prepared in triplicate and inoculated at an initial cell density of about 7.0 log CFU/ml well water. At 10^C, the cell density of five STEC strains fell below the detection limit of 0.8 log CFU/ml by day 56. Of the ten persisting strains, four showed superior survival with cell densities decreasing to an average of about 5 log CFU/ml while the remaining six strains showed moderate levels of survival, decreasing to an average cell density of about 3 log CFU/ml. At 22^C, strain H32 (genotype I) and H15 (genotype B) persisted at 1.1 log CFU/ml and 2.2 log CFU/ml in 56 days, respectively. The other 13 STEC strains dropped below the detection limit between weeks 3 to 8. The 15 strains demonstrated highly variable levels of survival with no correlation between ERIC-genotypes or serogroups and the strains' ability to persist in the well water samples. Although strain H32 (O157:H7) persisted significantly longer than strain H22 (O157:H7) in natural well water at both 10 and 22^C, both strains survived equally well in sterile well water, indicating that individual STEC strains vary in their ability to compete with background microbial populations.  相似文献   

16.
Water-binding properties of myofibrils extracted from porcine muscle, and added hemoglobin with and without exposure to H2O2, were characterized using low-field proton NMR T2 relaxometry. The effects of pH and ionic strength in the samples were investigated as pH was adjusted to 5.4, 6.2, and 7.0 and ionic strength was adjusted to 0.29, 0.46, and 0.71 M, respectively. The formation of dityrosine as a measure of oxidative protein cross-linking revealed a significant increase in dityrosine concentrations upon H2O2 activation. The formation of dityrosine was strongly pH-dependent and increased with decreasing pH. In addition, increased levels of thiobarbituric acid reactive substances were observed upon addition of H2O2, implying that lipid oxidation was enhanced, however, with a different oxidation pattern as compared to the myofibrillar proteins. Low-field NMR relaxation measurements revealed reduced T2 relaxation times upon H2O2 activation, which corresponds to reduced water-holding capacity upon oxidation. However, a direct relationship between degree of oxidation and T2 relaxation time was not observed with various pH values and ionic strengths, and further studies are needed for a complete understanding of the effect of oxidation on myofibrillar functionality.  相似文献   

17.
The risk of enteropathogens to food and water is highly dependent on their survival in soil environments. Here, the effects of soil type, particle size, the presence of natural organic matter (NOM) or Fe/Al (hydro)oxides on pathogenic Escherichia coli O157:H7 survival in sterilized soil particles were assessed through survival, attachment, metabolic activity, and qRT-PCR analyses. The abundance of inoculated E. coli O157:H7 in Brown soil (Alfisol) particles increased 0.6–1.4 log10 CFU/g within 3 days (except for NOM-stripped clay), while that in Red soil (Ultisol) particles decreased rapidly in 8 days post-inoculation. Additionally, survival of bacteria was significantly enhanced when Fe/Al (hydro)oxides had been removed from Red soil particles. For the two soils, E. coli O157:H7 survived the longest in NOM-present clays and the bacterial adenosine 5′-triphosphate (ATP) levels were 0.7–2.0 times greater in clays than in sands and silts on day 8. Moreover, clays were more effective than silts and sands in binding cells and changing the expressions of acetate pathway-associated genes (pta and ackA). For silts and sands, E. coli O157:H7 decayed more rapidly in the presence of NOM and similar trends of bacterial ATP levels were observed between NOM-stripped and NOM-present soil particles, indicating that the primary role of NOM was not as a nutrient supply. These findings indicate that soil particles function mainly through attachment to change the metabolic pathway of E. coli O157:H7 and ultimately impact the survival of bacterial pathogens in soils.  相似文献   

18.
《Applied soil ecology》2011,47(3):398-404
The inactivation of Escherichia coli O157:H7 (CCUG 44857) and Salmonella enterica serovar Typhimurium was investigated in two agricultural soils (sandy loam and silty clay) amended with poultry manure, cattle manure slurry or human urine. The study was performed in soil lysimeters placed outdoors, and was repeated over two consecutive years. The amendments, inoculated with E. coli O157:H7 and Salmonella Typhimurium, were mixed with soil on the top of the lysimeters. Samples were collected from the top 5-cm layer of each lysimeter at regular intervals, and the inactivation was monitored over 6 months, by the plate spread method and by enrichment. The inactivation was modelled by fitting a non-linear model to the data, and pathogen reduction times were calculated (90 and 99% reduction). The results showed that the inactivation of E. coli O157:H7 and Salmonella Typhimurium varied depending on the manure type used and its carbon content. The longest inactivation time occurred in samples amended with poultry manure, in which both E. coli O157:H7 and Salmonella Typhimurium were detected up to day 90 with the spread plate method. The most rapid inactivation for both pathogens occurred in soil amended with urine. However, low amounts of culturable E. coli O157:H7 and Salmonella Typhimurium were detected by enrichment throughout the study period (180 days), regardless of manure type.  相似文献   

19.

Purpose

The Escherichia coli (E. coli) O157:H7 survival dynamics in original and pH-modified agricultural soils were investigated to determinate how E. coli O157:H7 survival responded to the pH values of different soils, identify the relationships between E. coli O157:H7 survival time (t d ) and soil properties, and assess the potential pathogen contamination after soil pH changed.

Materials and methods

The six soil samples were collected from different provinces of China, and 18 pH-modified soil samples were obtained from original soils by treating the original soils with direct electric current. The E. coli O157:H7 cells were inoculated into 24 soils and incubated at soil moisture of ?33 kPa and 25 °C. The soils were sampled for determining the numbers of E. coli O157:H7 at given time intervals over the incubation. The effects of soil pH change and other properties on the t d values were analyzed.

Results and discussion

The t d values in the test soils were between 7.1—24.7 days. Results indicate that soil pH, texture, and free Fe2O3 (Fed) were the most important factors impacting the t d values in the test soils. Further, the response of E. coli O157:H7 survival to pH change varied with different soils. In the acidic soils (shorter t d values), the t d values decreased as the pH decreased and Fed increased, while in the neutral or alkaline soils (pH?≥?6.45, longer t d values), the t d values did not change significantly with pH.

Conclusions

The changes of amorphous and free sesquioxides induced by pH change might strengthen the response of E. coli O157:H7 survival to soil pH. Closer attention should be paid to E. coli O157:H7 long survival in soils and its potential environmental contamination risk.  相似文献   

20.
中性电解水对鸡蛋表面的清洗灭菌效果   总被引：3，自引：4，他引：3  
为寻求一种高效、安全、无污染的禽蛋清洗消毒剂,采用无隔膜电解装置电解稀盐酸溶液制备中性电解水（pH值6.0～7.5）考查不同有效氯浓度、处理时间和温度条件下中性电解水对鸡蛋人工接种鸡白痢沙门氏菌（Salmonella pullorum,鸡蛋表面的初始菌落数对数为6.19～6.26 log10 (cfu/g)）和大肠杆菌O157:H7（鸡蛋表面的初始菌落数对数为6.12～6.19 log10 (cfu/g)）的杀灭效果。结果表明,中性电解水对2种病菌均具有较强的杀灭效果,其杀菌效果随着有效氯浓度和处理时间的增加而增强,但温度对中性电解水的杀菌效果影响不显著。对菌悬液的杀菌试验表明：当中性电解水有效氯质量浓度为1.5 mg/L时,可以在20℃下3 min内完全杀灭鸡白痢沙门氏菌（初始含菌数的对数为 8.12 log10 (cfu/mL)）;质量浓度为2 mg/L时,可以100%杀灭大肠杆菌O157:H7（初始含菌数的对数为7.78 log10 (cfu/mL)）。当中性电解水清洗消毒被人工污染的鸡蛋表面时,有效氯质量浓度为12 mg/L、处理3 min可将鸡蛋表面的鸡白痢沙门氏菌全部杀灭,大肠杆菌O157:H7菌落数对数降低到1.0 log10 (cfu/g) 以下,且处理废液中没有残存菌,无二次污染问题。因此,中性电解水可以代替化学杀菌剂应用于鸡蛋清洗消毒。  相似文献   

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