Cations Reduce Antimicrobial Efficacy of Lysozyme-Chelator Combinations

2004 ◽  
Vol 67 (2) ◽  
pp. 285-294 ◽  
Author(s):  
J. S. BOLAND ◽  
P. M. DAVIDSON ◽  
B. BRUCE ◽  
J. WEISS
Keyword(s):  
Mechanistic Model ◽  
Monovalent Cation ◽  
Antimicrobial Efficacy ◽  
Titration Calorimetry ◽  
Escherichia Coli O157 ◽  
Tetraacetic Acid ◽  
Mineral Salts ◽  
E Coli ◽  
Strain Type ◽  
Antimicrobial Effectiveness

Reduction of the antimicrobial efficacy of lysozyme-chelator combinations against two Escherichia coli O157:H7 strains on addition of mineral salts was studied. The objective of the study was to determine the effect of type and concentration of mono-, di-, and trivalent mineral salts on the antimicrobial effectiveness of lysozyme and various chelators against E. coli O157:H7. Seven salts (Al3+, Ca2+, Fe2+, Fe3+, K+, Mg2+, and Na+) at 1 to 10 mM were added to aqueous solutions of lysozyme and disodium ethylenediamine tetraacetic acid (EDTA), disodium pyrophosphate (DSPP), or pentasodium tripolyphosphate (PSTPP) at pH 6, 7, or 8 and applied to cultures of E. coli O157:H7 strains 932 and H1730. Inhibitory activity of lysozyme chelator combinations against both strains was completely lost after addition of ≥1 mM Ca2+ and Mg2+ at pH 7 and 8. At pH 6, antimicrobial activity of lysozyme-EDTA against both strains was retained in the presence of calcium or magnesium cations. DSPP-lysozyme inhibited strain H1730 at pH 6 despite the presence of Mg2+. Concentrations above 4 mM Fe2+ neutralized activity of all lysozyme-chelator combinations. Reversal of inhibition by lysozyme-chelator complexes by the monovalent Na+ and K+ ions depended on E. coli O157:H7 strain type. Neither monovalent cation reversed inhibition of strain 932. However, Na+ and K+ reversed lysozyme-chelator inhibition of strain H1730. The addition of ≥1 mM Fe3+ or Al3+ was effective in reversing inhibition of both strains by lysozyme and EDTA at pH 6, 7, and 8. Isothermal titration calorimetry was used to determine the amount of ion-speci c competitive binding of free cations by EDTA-lysozyme combinations. A mechanistic model for the antimicrobial functionality of chelator-lysozyme combinations is proposed.

Inhibition of Escherichia coli O157:H7 in Ripening Dry Fermented Sausage by Ground Yellow Mustard

2008 ◽  
Vol 71 (3) ◽  
pp. 486-493 ◽  
Author(s):  
GARY H. GRAUMANN ◽  
RICHARD A. HOLLEY
Keyword(s):  
Escherichia Coli ◽  
Starter Culture ◽  
Escherichia Coli O157 ◽  
Fermented Sausage ◽  
Yellow Mustard ◽  
E Coli ◽  
Dry Fermented Sausage ◽  
Hydrolysis Of ◽  
Antimicrobial Effectiveness ◽  
Dry Sausage

Compounds generated by the enzymatic hydrolysis of glucosinolates naturally present in mustard powder are potently bactericidal against Escherichia coli O157:H7. Because E. coli O157:H7 can survive the dry fermented sausage manufacturing process, 2, 4, and 6% (wt/wt) nondeheated (hot) mustard powder or 6% (wt/wt) deheated (cold) mustard powder were added to dry sausage batter inoculated with E. coli O157:H7 at about 7 log CFU/g to evaluate the antimicrobial effectiveness of the powders. Reductions in E. coli O157:H7 populations, changes in pH and water activity (aw), effects on starter culture (Pediococcus pentosaceus and Staphylococcus carnosus) populations, and effects of mustard powder on sausage texture (shear) were monitored during ripening. Nondeheated mustard powder at 2, 4, and 6% in dry sausage (0.90 aw) resulted in significant reductions in E. coli O157:H7 (P < 0.05) of 3.4, 4.4, and 6.9 log CFU/g, respectively, within 30 days of drying. During fermentation and drying, mustard powder did not affect P. pentosaceus and S. carnosus activity in any of the treatments. Extension of drying to 36 and 48 days reduced E. coli O157:H7 by >5 log CFU/g in the 4 and 2% mustard powder treatments, respectively. The 6% deheated mustard powder treatment provided the most rapid reductions of E. coli O157:H7 (yielding <0.20 log CFU/g after 24 days) by an unknown mechanism and was the least detrimental (P < 0.05) to sausage texture.

Inactivation of Escherichia coli O157:H7 and Salmonella and Native Microbiota on Fresh Strawberries by Antimicrobial Washing and Coating

2018 ◽  
Vol 81 (8) ◽  
pp. 1227-1235 ◽  
Author(s):  
MINGMING GUO ◽  
TONY Z. JIN ◽  
JOSHUA B. GURTLER ◽  
XUETONG FAN ◽  
MADHAV P. YADAV
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Allyl Isothiocyanate ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Native Microflora ◽  
Pathogen Populations ◽  
Antimicrobial Treatments ◽  
Antimicrobial Effectiveness

ABSTRACT Antimicrobial washing (AW), antimicrobial coating (AC), and a combination of washing followed by coating (AW+AC) were evaluated for their ability to inactivate artificially inoculated foodborne pathogens and native microbiota on strawberries stored at 4°C. Strawberries were inoculated with a six-strain composite of Escherichia coli O157:H7 and Salmonella; treated by AW, AC, or AW+AC; and stored at 4°C for 3 weeks. The washing solution contained 90 ppm of peracetic acid, and the coating solution consisted of chitosan (1%, w/v), allyl isothiocyanate (1%, v/v), and corn-bio fiber gum (5%, w/v). The effectiveness of the antimicrobial treatments against E. coli O157:H7 and Salmonella pathogens and native microflora on strawberries and their impact on fruit quality (appearance, weight loss, color, and firmness) were determined. By the end of storage, pathogen populations on strawberries were 2.5 (AW+AC), 2.9 (AC), 3.8 (AW), and 4.2 log CFU for the positive (untreated) control. AW+AC treatments also inactivated the greatest population of native microflora, followed by the AC treatment alone. AW+AC treatments showed additional antimicrobial effectiveness against these two pathogens and native microflora. Both AW+AC and AC treatments preserved the color, texture, and appearance of strawberries throughout storage. The coating treatments (AW+AC and AC alone) further reduced the loss of moisture throughout storage. The AW treatment was the least effective in reducing populations of pathogens and native microflora and in maintaining the quality of strawberries throughout storage. This study demonstrates a method to improve the microbiological safety, shelf life, and quality of strawberries.

Antimicrobial Effects of Weak Acids on the Survival of Escherichia coli O157:H7 under Anaerobic Conditions†‡

2011 ◽  
Vol 74 (6) ◽  
pp. 893-898 ◽  
Author(s):  
HUIYING J. LU ◽  
FREDERICK BREIDT ◽  
ILENYS M. PÉREZ-DÍAZ ◽  
JASON A. OSBORNE
Keyword(s):  
Escherichia Coli ◽  
Food Products ◽  
Escherichia Coli O157 ◽  
Weak Acids ◽  
Anaerobic Conditions ◽  
Antimicrobial Effects ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction ◽  
Antimicrobial Effectiveness

Outbreaks of disease due to vegetative bacterial pathogens associated with acid foods (such as apple cider) have raised concerns about acidified vegetables and related products that have a similar pH (3.2 to 4.0). Escherichia coli O157:H7 and related strains of enterohemorrhagic E. coli (EHEC) have been identified as the most acid resistant vegetative pathogens in these products. Previous research has shown that the lack of dissolved oxygen in many hermetically sealed acid or acidified food products can enhance survival of EHEC compared with their survival under aerobic conditions. We compared the antimicrobial effects of several food acids (acetic, malic, lactic, fumaric, benzoic, and sorbic acids and sulfite) on a cocktail of EHEC strains under conditions representative of non–heat-processed acidified vegetables in hermetically sealed jars, holding the pH (3.2) and ionic strength (0.342) constant under anaerobic conditions. The overall antimicrobial effectiveness of weak acids used in this study was ranked, from most effective to least effective: sulfite > benzoic acid > sorbic acid > fumaric acid > l- and d-lactic acid > acetic acid > malic acid. These rankings were based on the estimated protonated concentrations required to achieve a 5-log reduction in EHEC after 24 h of incubation at 30°C. This study provides information that can be used to formulate safer acid and acidified food products and provides insights about the mode of action of weak acids against EHEC.

scholarly journals In Vivo and Ex Vivo Evaluations of Bacteriophages e11/2 and e4/1c for Use in the Control of Escherichia coli O157:H7

2010 ◽  
Vol 76 (21) ◽  
pp. 7210-7216 ◽  
Author(s):  
Lucia Rivas ◽  
Brid Coffey ◽  
Olivia McAuliffe ◽  
Mary J. McDonnell ◽  
Catherine M. Burgess ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Limit Of Detection ◽  
Ex Vivo ◽  
Escherichia Coli O157 ◽  
Fecal Shedding ◽  
E Coli ◽  
Significant Difference ◽  
Phage Cocktail ◽  
Antimicrobial Effectiveness

ABSTRACT This study investigated the effect of bacteriophages (phages) e11/2 and e4/1c against Escherichia coli O157:H7 in an ex vivo rumen model and in cattle in vivo. In the ex vivo rumen model, samples were inoculated with either 103 or 106 CFU/ml inoculum of E. coli O157:H7 and challenged separately with each bacteriophage. In the presence of phage e11/2, the numbers of E. coli O157:H7 bacteria were significantly (P < 0.05) reduced to below the limit of detection within 1 h. Phage e4/1c significantly (P < 0.05) reduced E. coli O157:H7 numbers within 2 h of incubation, but the number of surviving E. coli O157:H7 bacteria then remained unchanged over a further 22-h incubation period. The ability of a phage cocktail of e11/2 and e4/1c to reduce the fecal shedding of E. coli O157:H7 in experimentally inoculated cattle was then investigated in two cattle trials. Cattle (yearlings, n = 20 for trial one; adult fistulated cattle, n = 2 for trial two) were orally inoculated with 1010 CFU of E. coli O157:H7. Animals (n = 10 for trial one; n = 1 for trial two) were dosed daily with a bacteriophage cocktail of 1011 PFU for 3 days postinoculation. E. coli O157:H7 and phage numbers in fecal and/or rumen samples were determined over 7 days postinoculation. E. coli O157:H7 numbers rapidly declined in all animals within 24 to 48 h; however, there was no significant difference (P > 0.05) between the numbers of E. coli O157:H7 bacteria shed by the phage-treated or control animals. Phages were recovered from the rumen but not from the feces of the adult fistulated animal in trial two but were recovered from the feces of the yearling animals in trial one. While the results from the rumen model suggest that phages are effective in the rumen, further research is required to improve the antimicrobial effectiveness of phages for the elimination of E. coli O157:H7 in vivo.

Comparison of Antimicrobial Efficacy of Multiple Beef Hide Decontamination Strategies To Reduce Levels of Escherichia coli O157:H7 and Salmonella

2008 ◽  
Vol 71 (11) ◽  
pp. 2223-2227 ◽  
Author(s):  
BRANDON A. CARLSON ◽  
JOHN RUBY ◽  
GARY C. SMITH ◽  
JOHN N. SOFOS ◽  
GINA R. BELLINGER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Acetic Acid ◽  
Sodium Hydroxide ◽  
Organic Material ◽  
Sodium Sulfide ◽  
Sodium Metasilicate ◽  
Antimicrobial Efficacy ◽  
Escherichia Coli O157 ◽  
E Coli

This study involved a comparison of the antimicrobial efficacy of several beef hide decontamination interventions to identify those that more effectively reduced levels of Escherichia coli O157:H7 and Salmonella. Whole beef hides were inoculated with E. coli O157:H7 and Salmonella and decontaminated with sprays of solutions of acetic acid (AA; 10%, 55°C), lactic acid (LA; 10%, 55°C), sodium hydroxide (SH; 3%, 23°C), sodium metasilicate (SM; 4%, 23°C), or sodium hydroxide (1.5%), followed by high-pressure washing with chlorinated (0.02%) water (SHC; both applied at 23°C) or water (W; 23°C) or by deluging with solutions of potassium cyanate (PC; 2.4%, 30°C) or sodium sulfide (SS; 6.2%, 30°C). All spraying treatments (AA, LA, SH, SM, and SHC) resulted in removal of visual organic material, whereas the dehairing treatments (PC and SS) successfully removed hair along with visual organic material. The PC, SS, and SHC treatments resulted in the greatest reductions of E. coli O157:H7 (P &lt; 0.05), by 5.1, 4.8, and 5.0 log CFU/cm2, respectively. The SS and SHC treatments decreased Salmonella by 4.2 and 4.4 log CFU/cm2, respectively, compared with the water treatment, which reduced levels by 1.7 log CFU/cm2 (P &lt; 0.05). The SH, AA, and LA treatments also lowered both E. coli O157:H7 and Salmonella by at least 2.0 log CFU/cm2. The treatments that were effective in this study deserve further consideration for commercial implementation as hide decontamination interventions.

Comparison of EDTA and Apo-Lactoferrin with Lysozyme on the Growth of Foodborne Pathogenic and Spoilage Bacteria

1994 ◽  
Vol 57 (1) ◽  
pp. 62-65 ◽  
Author(s):  
K. D. PAYNE ◽  
S. P. OLIVER ◽  
P. M. DAVIDSON
Keyword(s):  
Escherichia Coli ◽  
Slow Growth ◽  
Ethylenediaminetetraacetic Acid ◽  
Antimicrobial Effect ◽  
Practical Significance ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Spoilage Bacteria ◽  
Practical Effect ◽  
Antimicrobial Effectiveness

Combinations of ethylenediaminetetraacetic acid (EDTA) or apo-lactoferrin (Apo-Lf) and lysozyme were evaluated for their antimicrobial effectiveness in ultra-high temperature pasteurized milk against Pseudomonas fluorescens, Salmonella typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes. Neither P. fluorescens nor S. typhimurium growth was influenced by EDTA, Apo-Lf or lysozyme alone or in combinations. Escherichia coli O157:H7 was inhibited by EDTA alone, but no increase in antimicrobial effectiveness was noted in the presence of lysozyme. In contrast, EDTA and lysozyme had a significant interactive antimicrobial effect against L. monocytogenes. Apo-Lf, at concentrations up to 2.5 mg/ml, displayed similar inhibition patterns with lysozyme against the E. coli O157:H7 and L. monocytogenes however, the magnitude of inhibition was much less and of little practical significance. When evaluated over time, EDTA (1.5–2.5 mg/ml)-lysozyme (150 μg/ml) slowed growth of E. coli and was bactericidal to L monocytogenes. Apo-lactoferrin (15 mg/ml)-lysozyme (150 μg/ml) had little practical effect on E. coli growth but did slow growth of L. monocytogenes.

Antimicrobial Effects of Zataria multiflora and Ocimum basilicum on Escherichia coli O157:H7 During Ripening of Traditional Lighvan Cheese

2020 ◽  
Vol 16 (3) ◽  
pp. 373-380
Author(s):  
Mohammad B. Zendeh ◽  
Vadood Razavilar ◽  
Hamid Mirzaei ◽  
Khosrow Mohammadi
Keyword(s):  
Escherichia Coli ◽  
Essential Oils ◽  
Dairy Products ◽  
Antimicrobial Agents ◽  
Escherichia Coli O157 ◽  
Zataria Multiflora ◽  
Antimicrobial Effects ◽  
E Coli ◽  
Common Causes ◽  
Lighvan Cheese

Background: Escherichia coli O157:H7 is one of the most common causes of contamination in Lighvan cheese processing. Using from natural antimicrobial essential oils is applied method to decrease the rate of microbial contamination of dairy products. The present investigation was done to study the antimicrobial effects of Z. multiflora and O. basilicum essential oils on survival of E. coli O157:H7 during ripening of traditional Lighvan cheese. Methods: Leaves of the Z. multiflora and O. basilicum plants were subjected to the Clevenger apparatus. Concentrations of 0, 100 and 200 ppm of the Z. multiflora and 0, 50 and 100 ppm of O. basilicum essential oils and also 103 and 105 cfu/ml numbers of E. coli O157:H7 were used. The numbers of the E. coli O157:H7 bacteria were analyzed during the days 0, 30, 60 and 90 of the ripening period. Results: Z. multiflora and O. basilicum essential oils had considerable antimicrobial effects against E. coli O157:H7. Using the essential oils caused decrease in the numbers of E. coli O157:H7 bacteria in 90th days of ripening (P <0.05). Using from Z. multiflora at concentration of 200 ppm can reduce the survival of E. coli O157:H7 in Lighvan cheese. Conclusion: Using Z. multiflora and O. basilicum essential oils as good antimicrobial agents can reduce the risk of foodborne bacteria and especially E. coli O157:H7 in food products.

Microbiological Examination of Vegetable Seed Sprouts in Korea

2009 ◽  
Vol 72 (4) ◽  
pp. 856-859 ◽  
Author(s):  
HOIKYUNG KIM ◽  
YOUNGJUN LEE ◽  
LARRY R. BEUCHAT ◽  
BONG-JUNE YOON ◽  
JEE-HOON RYU
Keyword(s):  
Microbiological Quality ◽  
Aerobic Bacteria ◽  
Escherichia Coli O157 ◽  
Enterobacter Sakazakii ◽  
Department Stores ◽  
E Coli ◽  
Traditional Markets ◽  
Radish Sprouts ◽  
Online Stores

Sprouted vegetable seeds used as food have been implicated as sources of outbreaks of Salmonella and Escherichia coli O157:H7 infections. We profiled the microbiological quality of sprouts and seeds sold at retail shops in Seoul, Korea. Ninety samples of radish sprouts and mixed sprouts purchased at department stores, supermarkets, and traditional markets and 96 samples of radish, alfalfa, and turnip seeds purchased from online stores were analyzed to determine the number of total aerobic bacteria (TAB) and molds or yeasts (MY) and the incidence of Salmonella, E. coli O157:H7, and Enterobacter sakazakii. Significantly higher numbers of TAB (7.52 log CFU/g) and MY (7.36 log CFU/g) were present on mixed sprouts than on radish sprouts (6.97 and 6.50 CFU/g, respectively). Populations of TAB and MY on the sprouts were not significantly affected by location of purchase. Radish seeds contained TAB and MY populations of 4.08 and 2.42 log CFU/g, respectively, whereas populations of TAB were only 2.54 to 2.84 log CFU/g and populations of MY were 0.82 to 1.69 log CFU/g on alfalfa and turnip seeds, respectively. Salmonella and E. coli O157:H7 were not detected on any of the sprout and seed samples tested. E. sakazakii was not found on seeds, but 13.3% of the mixed sprout samples contained this potentially pathogenic bacterium.

An Aggregation-Induced Emission Material Labeling Antigen-Based Lateral Flow Immunoassay Strip for Rapid Detection of Escherichia coli O157:H7

2021 ◽  
pp. 247263032098193
Author(s):  
Cheng Liu ◽  
Shuiqin Fang ◽  
Yachen Tian ◽  
Youxue Wu ◽  
Meijiao Wu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rapid Detection ◽  
Foodborne Pathogen ◽  
Test Strip ◽  
Lateral Flow ◽  
Detection Sensitivity ◽  
Lateral Flow Immunoassay ◽  
Escherichia Coli O157 ◽  
Aggregation Induced Emission ◽  
E Coli

Escherichia coli O157:H7 ( E. coli O157:H7) is a dangerous foodborne pathogen, mainly found in beef, milk, fruits, and their products, causing harm to human health or even death. Therefore, the detection of E. coli O157:H7 in food is particularly important. In this paper, we report a lateral flow immunoassay strip (LFIS) based on aggregation-induced emission (AIE) material labeling antigen as a fluorescent probe for the rapid detection of E. coli O157:H7. The detection sensitivity of the strip is 105 CFU/mL, which is 10 times higher than that of the colloidal gold test strip. This method has good specificity and stability and can be used to detect about 250 CFU of E. coli O157:H7 successfully in 25 g or 25 mL of beef, jelly, and milk. AIE-LFIS might be valuable in monitoring food pathogens for rapid detection.

Bacteriophages reduce Escherichia coli O157:H7 levels in experimentally inoculated sheep

2009 ◽  
Vol 89 (2) ◽  
pp. 285-293 ◽  
Author(s):  
S J Bach ◽  
R P Johnson ◽  
K. Stanford ◽  
T A McAllister
Keyword(s):  
Escherichia Coli ◽  
Oral Administration ◽  
Coliform Bacteria ◽  
Escherichia Coli O157 ◽  
Fecal Shedding ◽  
Total Coliforms ◽  
E Coli ◽  
Oral Inoculation ◽  
Experimental Treatments ◽  
And Control

Bacteriophage biocontrol has potential as a means of mitigating the prevalence of Escherichia coli O157:H7 in ruminants. The efficacy of oral administration of bacteriophages for reducing fecal shedding of E. coli O157:H7 by sheep was evaluated using 20 Canadian Arcott rams (50.0 ± 3.0) housed in four rooms (n = 5) in a contained facility. The rams had ad libitum access to drinking water and a pelleted barley-based total mixed ration, delivered once daily. Experimental treatments consisted of administration of E. coli O157:H7 (O157), E. coli O157:H7+bacteriophages (O157+phage), bacteriophages (phage), and control (CON). Oral inoculation of the rams with 109 CFU of a mixture of four nalidixic acid-resistant strains of E. coli O157:H7 was performed on day 0. A mixture of 1010 PFU of bacteriophages P5, P8 and P11 was administered on days -2, -1, 0, 6 and 7. Fecal samples collected on 14 occasions over 21 d were analyzed for E. coli O157:H7, total E. coli, total coliforms and bacteriophages. Sheep in treatment O157+phage shed fewer (P < 0.05) E. coli O157:H7 than did sheep in treatment O157. Populations of total coliforms and total E. coli were similar (P < 0.05) among treatments, implying that bacteriophage lysis of non-target E. coli and coliform bacteria in the gastrointestinal tract did not occur. Bacteriophage numbers declined rapidly over 21 d, which likely reduced the chance of collision between bacteria and bacteriophage. Oral administration of bacteriophages reduced shedding of E. coli O157:H7 by sheep, but a delivery system that would protect bacteriophages during passage through the intestine may increase the effectiveness of this strategy as well as allow phage to be administered in the feed.Key words: Escherichia coli O157:H7, bacteriophage, sheep, environment, coliforms

Sign in / Sign up

Export Citation Format

Share Document