Inactivation of Escherichia coli O157:H7 and Salmonella Typhimurium DT 104 on Alfalfa Seeds by Levulinic Acid and Sodium Dodecyl Sulfate

2010 ◽  
Vol 73 (11) ◽  
pp. 2010-2017 ◽  
Author(s):  
TONG ZHAO ◽  
PING ZHAO ◽  
MICHAEL P. DOYLE
Keyword(s):  
Escherichia Coli ◽  
Sodium Dodecyl Sulfate ◽  
Salmonella Typhimurium ◽  
Levulinic Acid ◽  
Tap Water ◽  
Sodium Dodecyl ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Dodecyl Sulfate ◽  
Alfalfa Seeds

Studies were conducted to determine the best concentration and exposure time for treatment of alfalfa seeds with levulinic acid plus sodium dodecyl sulfate (SDS) to inactivate Escherichia coli O157:H7 and Salmonella without adversely affecting seed germination. Alfalfa seeds inoculated with a five-strain mixture of E. coli O157:H7 or Salmonella Typhimurium were dried in a laminar flow hood at 21°C for up to 72 h. Inoculated alfalfa seeds dried for 4 h then treated for 5 min at21°C with 0.5% levulinic acid and 0.05% SDS reduced the population of E. coli O157:H7 and Salmonella Typhimurium by 5.6 and 6.4 log CFU/g, respectively. On seeds dried for 72 h, treatment with 0.5% levulinic acid and 0.05% SDS for 20 min at 21°C reduced E. coli O157:H7 and Salmonella Typhimurium populations by 4 log CFU/g. Germination rates of alfalfa seeds treated with 0.5% levulinic acid plus 0.05% SDS for up to 1 h at 21°C were compared with a treatment of 20,000 ppm of calcium hypochlorite or tap water only. Treatment of alfalfa seeds with 0.5% levulinic acid plus 0.05% SDS for 5 min at 21°C resulted in a >3.0-log inactivation of E. coli O157:H7 and Salmonella.

Reductions of Shiga Toxin–Producing Escherichia coli and Salmonella Typhimurium on Beef Trim by Lactic Acid, Levulinic Acid, and Sodium Dodecyl Sulfate Treatments

2014 ◽  
Vol 77 (4) ◽  
pp. 528-537 ◽  
Author(s):  
TONG ZHAO ◽  
PING ZHAO ◽  
DONG CHEN ◽  
RAVIRAJSINH JADEJA ◽  
YEN-CON HUNG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Sodium Dodecyl Sulfate ◽  
Salmonella Typhimurium ◽  
Bactericidal Activity ◽  
Shiga Toxin ◽  
Levulinic Acid ◽  
Sodium Dodecyl ◽  
E Coli ◽  
Dodecyl Sulfate

Studies were done at 21°C to determine the bactericidal activity of lactic acid, levulinic acid, and sodium dodecyl sulfate (SDS) applied individually and in combination on Shiga toxin–producing Escherichia coli (STEC) in pure culture and to compare the efficacy of lactic acid and levulinic acid plus SDS treatments applied by spray or immersion to inactivate STEC and Salmonella (107 CFU/cm2) on beef trim pieces (10 by 10 by 7.5 cm). Application of 3% lactic acid for 2 min to pure cultures was shown to reduce E. coli O26:H11, O45:H2, O111:H8, O103:H2, O121:H2, O145:NM, and O157:H7 populations by 2.1, 0.4, 0.3, 1.4, 0.3, 2.1, and 1.7 log CFU/ml, respectively. Treatment with 0.5% levulinic acid plus 0.05% SDS for <1 min reduced the populations of all STEC strains to undetectable levels (>6 log/ml reduction). Beef surface temperature was found to affect the bactericidal activity of treatment with 3% levulinic acid plus 2% SDS (LV-SDS). Treating cold (4°C) beef trim with LV-SDS at 21, 62, or 81°C for 30 s reduced E. coli O157:H7 by 1.0, 1.1, or 1.4 log CFU/cm2, respectively, whereas treating beef trim at 8°C with LV-SDS at 12°C for 0.1, 1, 3, or 5 min reduced E. coli O157:H7 by 1.4, 2.4, 2.5, or 3.3 log CFU/cm2, respectively. Spray treatment of beef trim at 4°C with 5% lactic acid only reduced the E. coli O157:H7 population by 1.3 log CFU/cm2. Treating beef trim at 8°C with LV-SDS for 1, 2, or 3 min reduced Salmonella Typhimurium by 2.1, 2.6, and >5.0 log CFU/cm2, respectively. Hand massaging the treated beef trim substantially reduced contamination of both pathogens, with no detectable E. coli O157:H7 or Salmonella Typhimurium (<5 CFU/cm2) on beef trim pieces treated with LV-SDS. Reduction of E. coli O157:H7 and Salmonella Typhimurium populations was enhanced, but bactericidal activity was affected by the meat temperature.

Efficacy of Levulinic Acid–Sodium Dodecyl Sulfate against Encephalitozoon intestinalis, Escherichia coli O157:H7, and Cryptosporidium parvum

2011 ◽  
Vol 74 (1) ◽  
pp. 140-144 ◽  
Author(s):  
YNES R. ORTEGA ◽  
MARIA P. TORRES ◽  
JESSICA M. TATUM
Keyword(s):  
Escherichia Coli ◽  
Sodium Dodecyl Sulfate ◽  
Cryptosporidium Parvum ◽  
Levulinic Acid ◽  
Sodium Dodecyl ◽  
In Vitro Cultivation ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Encephalitozoon Intestinalis ◽  
Dodecyl Sulfate

Foodborne parasites are characterized as being highly resistant to sanitizers used by the food industry. In 2009, a study reported the effectiveness of levulinic acid in combination with sodium dodecyl sulfate (SDS) in killing foodborne bacteria. Because of their innocuous properties, we studied the effects of levulinic acid and SDS at various concentrations appropriate for use in foods, on the viability of Cryptosporidium parvum and Encephalitozoon intestinalis. The viability of Cryptosporidium and E. intestinalis was determined by in vitro cultivation using the HCT-8 and RK-13 cell lines, respectively. Two Escherichia coli O157:H7 isolates were also used in the present study: strain 932 (a human isolate from a 1992 Oregon meat outbreak) and strain E 0018 (isolated from calf feces). Different concentrations and combinations of levulinic acid and SDS were tested for their ability to reduce infectivity of C. parvum oocysts (105), E. intestinalis spores (106), and E. coli O157:H7 (107/ml) when in suspension. Microsporidian spores were treated for 30 and 60 min at 20 ± 2°C. None of the combinations of levulinic acid and SDS were effective at inactivating the spores or oocysts. When Cryptosporidium oocysts were treated with higher concentrations (3% levulinic acid–2% SDS and 2% levulinic acid–1% SDS) for 30, 60, and 120 min, viability was unaffected. E. coli O157:H7, used as a control, was highly sensitive to the various concentrations and exposure times tested. SDS and levulinic acid alone had very limited effect on E. coli O157:H7 viability, but in combination they were highly effective at 30 and 60 min of incubation. In conclusion, Cryptosporidium and microsporidia are not inactivated when treated for various periods of time with 2% levulinic acid–1% SDS or 3% levulinic acid–2% SDS at 20°C, suggesting that this novel sanitizer cannot be used to eliminate parasitic contaminants in foods.

Inactivation of Salmonella and Escherichia coli O157:H7 on Lettuce and Poultry Skin by Combinations of Levulinic Acid and Sodium Dodecyl Sulfate

2009 ◽  
Vol 72 (5) ◽  
pp. 928-936 ◽  
Author(s):  
TONG ZHAO ◽  
PING ZHAO ◽  
MICHAEL P. DOYLE
Keyword(s):  
Escherichia Coli ◽  
Sodium Dodecyl Sulfate ◽  
Organic Acids ◽  
Levulinic Acid ◽  
Sodium Dodecyl ◽  
Escherichia Coli O157 ◽  
Bacterial Populations ◽  
E Coli ◽  
Dodecyl Sulfate ◽  
Chicken Feces

Four organic acids (lactic acid, acetic acid, caprylic acid, and levulinic acid) and sodium dodecyl sulfate (SDS) were evaluated individually or in combination for their ability to inactivate Salmonella and Escherichia coli O157:H7. Results from pure culture assays in water with the treatment chemical revealed that 0.5% organic acid and 0.05 to 1% SDS, when used individually, reduced pathogen cell numbers by ≤2 log CFU/ml within 20 min at 21°C. The combination of any of these organic acids at 0.5% with 0.05% SDS resulted in >7 log CFU/ml inactivation of Salmonella and E. coli O157:H7 within 10 s at 21°C. A combination of levulinic acid and SDS was evaluated at different concentrations for pathogen reduction on lettuce at 21°C, on poultry (wings and skin) at 8°C, and in water containing chicken feces or feathers at 21°C. Results revealed that treatment of lettuce with a combination of 3% levulinic acid plus 1% SDS for <20 s reduced both Salmonella and E. coli O157:H7 populations by >6.7 log CFU/g on lettuce. Salmonella and aerobic bacterial populations on chicken wings were reduced by >5 log CFU/g by treatment with 3% levulinic acid plus 2% SDS for 1 min. Treating water heavily contaminated with chicken feces with 3% levulinic acid plus 2% SDS reduced Salmonella populations by >7 log CFU/ml within 20 s. The use of levulinic acid plus SDS as a wash solution may have practical application for killing foodborne enteric pathogens on fresh produce and uncooked poultry.

scholarly journals Sodium Dodecyl Sulfate Hypersensitivity of clpP and clpB Mutants of Escherichia coli

2002 ◽  
Vol 68 (8) ◽  
pp. 4117-4121 ◽  
Author(s):  
Soumitra Rajagopal ◽  
Narasimhan Sudarsan ◽  
Kenneth W. Nickerson
Keyword(s):  
Escherichia Coli ◽  
Sodium Dodecyl Sulfate ◽  
Uronic Acid ◽  
Sodium Dodecyl ◽  
Immunoblot Analysis ◽  
Wild Type ◽  
E Coli ◽  
Dodecyl Sulfate ◽  
Shock Proteins ◽  
Western Immunoblot Analysis

ABSTRACT We studied the hypersensitivity of clpP and clpB mutants of Escherichia coli to sodium dodecyl sulfate (SDS). Both wild-type E. coli MC4100 and lon mutants grew in the presence of 10% SDS, whereas isogenic clpP and clpB single mutants could not grow above 0.5% SDS and clpA and clpX single mutants could not grow above 5.0% SDS. For wild-type E. coli, cellular ClpP levels as determined by Western immunoblot analysis increased ca. sixfold as the levels of added SDS increased from 0 to 2%. Capsular colanic acid, measured as uronic acid, increased ca. sixfold as the levels of added SDS increased from 2 to 10%. Based on these findings, 3 of the 19 previously identified SDS shock proteins (M. Adamowicz, P. M. Kelley, and K. W. Nickerson, J. Bacteriol. 173:229-233, 1991) are tentatively identified as ClpP, ClpX, and ClpB.

scholarly journals Toxicity Biosensor for Sodium Dodecyl Sulfate Using Immobilized Green Fluorescent Protein ExpressingEscherichia coli

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Lia Ooi ◽  
Lee Yook Heng ◽  
Asmat Ahmad
Keyword(s):  
Green Fluorescent Protein ◽  
Sodium Dodecyl Sulfate ◽  
Fluorescent Protein ◽  
Dynamic Range ◽  
Tap Water ◽  
Sodium Dodecyl ◽  
Mutant Gene ◽  
E Coli ◽  
Dodecyl Sulfate ◽  
Green Fluorescent

Green fluorescent protein (GFP) is suitable as a toxicity sensor due to its ability to work alone without cofactors or substrates. Its reaction with toxicants can be determined with fluorometric approaches. GFP mutant gene (C48S/S147C/Q204C/S65T/Q80R) is used because it has higher sensitivity compared to others GFP variants. A novel sodium dodecyl sulfate (SDS) toxicity detection biosensor was built by immobilizing GFP expressingEscherichia coliink-Carrageenan matrix. Cytotoxicity effect took place in the toxicity biosensor which leads to the decrease in the fluorescence intensity. The fabricatedE. coliGFP toxicity biosensor has a wide dynamic range of 4–100 ppm, with LOD of 1.7 ppm. Besides, it possesses short response time (<1 min), high reproducibility (0.76% RSD) and repeatability (0.72% RSD,R2>0.98), and long-term stability (46 days).E. coliGFP toxicity biosensor has been applied to detect toxicity induced by SDS in tap water, river water, and drinking water. High recovery levels of SDS indicated the applicability ofE. coliGFP toxicity biosensor in real water samples toxicity evaluation.

Inactivation of Escherichia coli O157:H7, Salmonella Typhimurium DT104, and Listeria monocytogenes on Inoculated Alfalfa Seeds with a Fatty Acid–Based Sanitizer

2006 ◽  
Vol 69 (3) ◽  
pp. 582-590 ◽  
Author(s):  
PASCALE M. PIERRE ◽  
ELLIOT T. RYSER
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Fatty Acid ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Reference Concentration ◽  
Glycerol Monolaurate ◽  
Alfalfa Seeds

Alfalfa seeds were inoculated with a three-strain cocktail of Escherichia coli O157:H7, Salmonella enterica subsp. enterica serovar Typhimurium DT104, or Listeria monocytogenes by immersion to contain ∼6 to 8 log CFU/g and then treated with a fatty acid–based sanitizer containing 250 ppm of peroxyacid, 1,000 ppm of caprylic and capric acids (Emery 658), 1,000 ppm of lactic acid, and 500 ppm of glycerol monolaurate at a reference concentration of 1×. Inoculated seeds were immersed at sanitizer concentrations of 5×, 10×, and 15× for 1, 3, 5, and 10 min and then assessed for pathogen survivors by direct plating. The lowest concentration that decreased all three pathogens by &gt;5 log was 15×. After a 3-min exposure to the 15× concentration, populations of E. coli O157:H7, Salmonella Typhimurium DT104, and L. monocytogenes decreased by &gt;5.45, &gt;5.62, and &gt;6.92 log, respectively, with no sublethal injury and no significant loss in seed germination rate or final sprout yield. The components of this 15× concentration (treatment A) were assessed independently and in various combinations to optimize antimicrobial activity. With inoculated seeds, treatment C (15,000 ppm of Emery 658, 15,000 ppm of lactic acid, and 7,500 ppm of glycerol monolaurate) decreased Salmonella Typhimurium, E. coli O157:H7, and L. monocytogenes by 6.23 and 5.57 log, 4.77 and 6.29 log, and 3.86 and 4.21 log after 3 and 5 min of exposure, respectively. Treatment D (15,000 ppm of Emery 658 and 15,000 ppm of lactic acid) reduced Salmonella Typhimurium by &gt;6.90 log regardless of exposure time and E. coli O157:H7 and L. monocytogenes by 4.60 and &gt;5.18 log and 3.55 and 3.14 log after 3 and 5 min, respectively. No significant differences (P &gt; 0.05) were found between treatments A, C, and D. Overall, treatment D, which contained Emery 658 and lactic acid as active ingredients, reduced E. coli O157:H7, Salmonella Typhimurium, and L. monocytogenes populations by 3.55 to &gt;6.90 log and may provide a viable alternative to the recommended 20,000 ppm of chlorine for sanitizing alfalfa seeds.

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