Comparison of Chlorine and a Prototype Produce Wash Product for Effectiveness in Killing Salmonella and Escherichia coli O157:H7 on Alfalfa Seeds

2001 ◽  
Vol 64 (2) ◽  
pp. 152-158 ◽  
Author(s):  
LARRY R. BEUCHAT ◽  
THOMAS E. WARD ◽  
CHARLES A. PETTIGREW
Keyword(s):  
Escherichia Coli ◽  
Human Health ◽  
Organic Material ◽  
Bacterial Pathogens ◽  
Environmental Hazards ◽  
Effective Alternative ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Alfalfa Seeds

Outbreaks of Salmonella and Escherichia coli O157:H7 infections associated with alfalfa and other seed sprouts have occurred with increased frequency in recent years. This study was undertaken to determine the efficacy of a liquid prototype produce wash product (Fit), compared with water and chlorinated water, in killing Salmonella and E. coli O157:H7 inoculated onto alfalfa seeds. We investigated the efficacy of treatments as influenced by seeds from two different lots obtained from two seeds suppliers and by two methods of inoculation. The efficacy of treatments was influenced by differences in seed lots and amount of organic material in the inoculum. Significant (α = 0.05) reductions in Salmonella populations on seeds treated with 20,000 ppm of chlorine or Fit for 30 min ranged from 2.3 to 2.5 log10 CFU/g and 1.7 to 2.3 log10 CFU/g, respectively. Reductions (α = 0.05) in E. coli O157:H7 ranged from 2.0 to 2.1 log10 CFU/g and 1.7 to more than 5.4 log10 CFU/g of seeds treated, respectively, with 20,000 ppm of chlorine or Fit. Compared with treatment with 200 ppm of chlorine, treatment with either 20,000 ppm of chlorine or Fit resulted in significantly higher reductions in populations of Salmonella and E. coli O157:H7. None of the treatments eliminated these pathogens as evidenced by their detection on enrichment of treated seeds. Considering the human health and environmental hazards associated with the use of 20,000 ppm of chlorine, Fit provides an effective alternative to chlorine as a treatment to significantly reduce bacterial pathogens that have been associated with alfalfa seeds.

Efficacy of Chemical Treatments in Eliminating Salmonella and Escherichia coli O157:H7 on Scarified and Polished Alfalfa Seeds

2001 ◽  
Vol 64 (10) ◽  
pp. 1489-1495 ◽  
Author(s):  
SARAH L. HOLLIDAY ◽  
ALAN J. SCOUTEN ◽  
LARRY R. BEUCHAT
Keyword(s):  
Escherichia Coli ◽  
Chemical Treatment ◽  
Organic Material ◽  
Pathogenic Bacteria ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Mechanical Abrasion ◽  
Chemical Treatments ◽  
The Impact ◽  
Alfalfa Seeds

Alfalfa seeds are sometimes subjected to a scarification treatment to enhance water uptake, which results in more rapid and uniform germination during sprout production. It has been hypothesized that this mechanical abrasion treatment diminishes the efficacy of chemical treatments used to kill or remove pathogenic bacteria from seeds. A study was done to compare the effectiveness of chlorine (20,000 ppm), H2O2 (8%), Ca(OH)2 (1%), Ca(OH)2 (1%) plus Tween 80 (1%), and Ca(OH)2 (1%) plus Span 20 (1%) treatments in killing Salmonella and Escherichia coli O157:H7 inoculated onto control, scarified, and polished alfalfa seeds obtained from two suppliers. The influence of the presence of organic material in the inoculum carrier on the efficacy of sanitizers was investigated. Overall, treatment with 1% Ca(OH)2 was the most effective in reducing populations of the pathogens. Reduction in populations of pathogens on seeds obtained from supplier 1 indicate that chemical treatments are less efficacious in eliminating the pathogens on scarified seeds compared to control seeds. However, the effectiveness of chemical treatment in removing Salmonella and E. coli O157:H7 from seeds obtained from supplier 2 was not markedly affected by scarification or polishing. The presence of organic material in the inoculum carrier did not have a marked influence on the efficacy of chemicals in reducing populations of test pathogens. Additional lots of control, scarified, and polished alfalfa seeds of additional varieties need to be tested before conclusions can be drawn concerning the impact of mechanical abrasion on the efficacy of chemical treatment in removing or killing Salmonella and E. coli O157:H7.

Chemical and Irradiation Treatments for Killing Escherichia coli O157:H7 on Alfalfa, Radish, and Mung Bean Seeds

2003 ◽  
Vol 66 (5) ◽  
pp. 767-774 ◽  
Author(s):  
M. L. BARI ◽  
E. NAZUKA ◽  
Y. SABINA ◽  
S. TODORIKI ◽  
K. ISSHIKI
Keyword(s):  
Escherichia Coli ◽  
Heat Treatment ◽  
Mung Bean ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Chemical Treatments ◽  
Dry Heat ◽  
Pathogen Populations ◽  
Dry Heat Treatment ◽  
Alfalfa Seeds

In this study, the effectiveness of dry-heat treatment in combination with chemical treatments (electrolyzed oxidizing [EO] water, califresh-S, 200 ppm of active chlorinated water) with and without sonication in eliminating Escherichia coli O157:H7 on laboratory-inoculated alfalfa, radish, and mung bean seeds was compared with that of dry-heat treatment in combination with irradiation treatment. The treatment of mung bean seeds with EO water in combination with sonication followed by a rinse with sterile distilled water resulted in reductions of approximately 4.0 log10 CFU of E. coli O157:H7 per g, whereas reductions of ca. 1.52 and 2.64 log10 CFU/g were obtained for radish and alfalfa seeds. The maximum reduction (3.70 log10 CFU/g) for mung bean seeds was achieved by treatment with califresh-S and chlorinated water (200 ppm) in combination with sonication and a rinse. The combination of dry heat, hot EO water treatment, and sonication was able to eliminate pathogen populations on mung bean seeds but was unable to eliminate the pathogen on radish and alfalfa seeds. Other chemical treatments used were effective in greatly reducing pathogen populations on radish and alfalfa seeds without compromising the quality of the sprouts, but these treatments did not result in the elimination of pathogens from radish and alfalfa seeds. Moreover, a combination of dry-heat and irradiation treatments was effective in eliminating E. coli O157:H7 on laboratory-inoculated alfalfa, radish, and mung bean seeds. An irradiation dose of 2.0 kGy in combination with dry heat eliminated E. coli O157:H7 completely from alfalfa and mung bean seeds, whereas a 2.5-kGy dose of irradiation was required to eliminate the pathogen completely from radish seeds. Dry heat in combination with irradiation doses of up to 2.0 kGy did not unacceptably decrease the germination percentage for alfalfa seeds or the length of alfalfa sprouts but did decrease the lengths of radish and mung bean sprouts.

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 >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 >5.45, >5.62, and >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 >6.90 log regardless of exposure time and E. coli O157:H7 and L. monocytogenes by 4.60 and >5.18 log and 3.55 and 3.14 log after 3 and 5 min, respectively. No significant differences (P > 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 >6.90 log and may provide a viable alternative to the recommended 20,000 ppm of chlorine for sanitizing alfalfa seeds.

Efficacy of Sanitizer Treatments on Survival and Growth Parameters of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on Fresh-Cut Pieces of Cantaloupe during Storage†

2015 ◽  
Vol 78 (7) ◽  
pp. 1288-1295 ◽  
Author(s):  
DIKE O. UKUKU ◽  
LIHAN HUANG ◽  
CHRISTOPHER SOMMERS
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Growth Parameters ◽  
Bacterial Pathogens ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Mesophilic Bacteria ◽  
Survival And Growth ◽  
Fresh Cut

For health reasons, people are consuming fresh-cut fruits with or without minimal processing and, thereby, exposing themselves to the risk of foodborne illness if such fruits are contaminated with bacterial pathogens. This study investigated survival and growth parameters of Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and aerobic mesophilic bacteria transferred from cantaloupe rind surfaces to fresh-cut pieces during fresh-cut preparation. All human bacterial pathogens inoculated on cantaloupe rind surfaces averaged ~4.8 log CFU/cm2, and the populations transferred to fresh-cut pieces before washing treatments ranged from 3 to 3.5 log CFU/g for all pathogens. A nisin-based sanitizer developed in our laboratory and chlorinated water at 1,000 mg/liter were evaluated for effectiveness in minimizing transfer of bacterial populations from cantaloupe rind surface to fresh-cut pieces. Inoculated and uninoculated cantaloupes were washed for 5 min before fresh-cut preparation and storage of fresh-cut pieces at 5 and 10°C for 15 days and at 22°C for 24 h. In fresh-cut pieces from cantaloupe washed with chlorinated water, only Salmonella was found (0.9 log CFU/g), whereas E. coli O157:H7 and L. monocytogenes were positive only by enrichment. The nisin-based sanitizer prevented transfer of human bacteria from melon rind surfaces to fresh-cut pieces, and the populations in fresh-cut pieces were below detection even by enrichment. Storage temperature affected survival and the growth rate for each type of bacteria on fresh-cut cantaloupe. Specific growth rates of E. coli O157:H7, Salmonella, and L. monocytogenes in fresh-cut pieces were similar, whereas the aerobic mesophilic bacteria grew 60 to 80% faster and had shorter lag phases.

Combination Treatments for Killing Escherichia coli O157:H7 on Alfalfa, Radish, Broccoli, and Mung Bean Seeds

2009 ◽  
Vol 72 (3) ◽  
pp. 631-636 ◽  
Author(s):  
M. L. BARI ◽  
D. NEI ◽  
K. ENOMOTO ◽  
S. TODORIKI ◽  
S. KAWAMOTO
Keyword(s):  
Escherichia Coli ◽  
Heat Treatment ◽  
Mung Bean ◽  
Germination Rate ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Dry Heat ◽  
Pathogen Populations ◽  
Dry Heat Treatment ◽  
Alfalfa Seeds

In this study, the effectiveness of prolonged dry-heat treatment (50°C) alone or in combination with chemical treatments (1% oxalic acid, 0.03% phytic acid, 50% ethanol, electrolyzed acidic water, and electrolyzed alkaline water) in eliminating Escherichia coli O157:H7 on laboratory-inoculated alfalfa, radish, broccoli, and mung bean seeds was compared with that of dry-heat treatment in combination with irradiation treatment. Dry-heat treatment for 17 or 24 h alone could reduce E. coli O157:H7 numbers to below detectable levels in radish, broccoli, and alfalfa seeds, but was unable to reduce the pathogen numbers to below the detectable level in mung bean seeds. In addition, dry-heat treatment for 17 h plus sanitizer treatments were effective in greatly reducing pathogen populations on radish, broccoli, and alfalfa seeds, without compromising the quality of the sprouts, but these treatments did not eliminate the pathogen from radish and alfalfa seeds. Seventeen hours of dry heat followed by a 1.0-kGy dose of irradiation completely eliminated E. coli O157:H7 from radish and mung bean seeds, whereas only a minimum radiation dose of 0.25 kGy was required to completely eliminate the pathogen from broccoli and alfalfa seeds. Dry heat in combination with radiation doses of up to 1.0 kGy did not negatively impact the seed germination rate or length of alfalfa, broccoli, and radish seeds or the length of alfalfa, broccoli, and radish sprouts, but did decrease the length of mung bean sprouts.

Comparison of Chemical Treatments to Eliminate Enterohemorrhagic Escherichia coli O157:H7 on Alfalfa Seeds

1999 ◽  
Vol 62 (4) ◽  
pp. 318-324 ◽  
Author(s):  
PETER J. TAORMINA ◽  
LARRY R. BEUCHAT
Keyword(s):  
Escherichia Coli ◽  
Germination Percentage ◽  
Enterohemorrhagic Escherichia Coli ◽  
Active Chlorine ◽  
Escherichia Coli O157 ◽  
Dramatic Decrease ◽  
E Coli ◽  
Surfactant Treatment ◽  
Chemical Treatments ◽  
Alfalfa Seeds

The focus of this study was to determine the efficacy of various chemicals in eliminating 2.04 to 3.23 log10 CFU/g of Escherichia coli O157:H7 from alfalfa seeds and to determine the survivability of the pathogen on seeds stored for prolonged periods at three temperatures. Significant (P ≤ 0.05) reductions in populations of E. coli O157:H7 on inoculated seeds were observed after treatments with 500 and 1,000 ppm of active chlorine (as Ca[OCl]2) for 3 but not 10 min and with ≥2,000 ppm of Ca(OCl)2 regardless of pretreatment with a surfactant. Treatment with 20,000 ppm of active chlorine failed to kill 2.68 log10 CFU/g of seeds. Acidified NaClO2 (500 ppm) was effective in reducing populations of the pathogen by >2 logs per g. Acidified ClO2 significantly reduced populations of E. coli O157:H7 on seeds at concentrations ≥100 ppm, and 500 ppm of ClO2 reduced the pathogen from 2.7 log10 CFU/g to <0.5 CFU/g. Chlorine (as NaOCl) was not effective at concentrations ≤1,000 ppm; significant reduction was achieved only after treatment with 2,000 ppm for 3 or 10 min. Notable reduction in populations was observed after treatment with 30 or 70% C2H3OH, but there was a dramatic decrease in germination percentage. Treatment with 0.2% H2O2 significantly reduced populations, and the organism was not detected by direct plating after treatment with ≥1% H2O2. Significant reduction in population of E. coli O157:H7 occurred after treatment with 1% trisodium phosphate, 40 ppm of Tsunami and Vortexx, and 1% Vegi-Clean. A significant decrease in the number of E. coli O157:H7 on dry seeds was observed within 1 week of storage at 25 and 37°C, but not at 5°C. Between 1 and 38 weeks, populations on seeds stored at 5°C remained relatively constant. The pathogen was recovered from alfalfa seeds initially containing 3.04 log10 CFU/g after storage at 25 or 37°C for 38 weeks but not 54 weeks.

Behavior of Enterohemorrhagic Escherichia coli O157:H7 on Alfalfa Sprouts during the Sprouting Process as Influenced by Treatments with Various Chemicals

1999 ◽  
Vol 62 (8) ◽  
pp. 850-856 ◽  
Author(s):  
PETER J. TAORMINA ◽  
LARRY R. BEUCHAT
Keyword(s):  
Escherichia Coli ◽  
Cold Storage ◽  
Treatment Method ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Chemical Treatments ◽  
Alfalfa Sprouts ◽  
Germinated Seeds ◽  
Alfalfa Seeds

The behavior of Escherichia coli O157:H7 on alfalfa seeds subjected to conditions similar to those used commercially to grow and market sprouts as it is affected by applications of NaOCl, Ca(OCl)2, acidified NaClO2, acidified ClO2, Na3PO4, Vegi-Clean, Tsunami, Vortexx, or H2O2 at various stages of the sprouting process was determined. Application of 2,000 ppm of NaOCl, 200 and 2,000 ppm of Ca(OCl)2, 500 ppm of acidified ClO2, 10,000 ppm of Vegi-Clean, 80 ppm of Tsunami, or 40 and 80 ppm of Vortexx to germinated seeds significantly reduced the population of E. coli O157:H7. With the exception of acidified NaOCl2 at 1,200 ppm, spray applications of these chemicals did not significantly reduce populations or control the growth of E. coli O157:H7 on alfalfa sprouts during the sprouting process. Populations of E. coli on alfalfa sprouts peaked at 6 to 7 log10 CFU/g 48 h after initiation of the sprouting process and remained stable despite further spraying with chemicals. The population of E. coli O157:H7 on sprouts as they entered cold storage at 9 ± 2°C remained essentially unchanged for up to 6 days. None of the chemical treatments evaluated was able to eliminate or satisfactorily reduce E. coli O157:H7 on alfalfa seeds and sprouts. Observations on the ability of E. coli O157:H7 to grow during production of alfalfa sprouts not subjected to chemical treatments are similar to those from a previous study in our laboratory on the behavior of Salmonella Stanley. Our results do not reveal a chemical treatment method to eliminate the pathogen from alfalfa sprouts. We have demonstrated that currently recommended procedures for sanitizing alfalfa seeds fail to eliminate E. coli O157:H7 and that the pathogen can grow to populations exceeding 7 log10 CFU/g of sprouts produced using techniques not dissimilar to those used in the sprout industry.

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.

Thermal Inactivation of Salmonella and Escherichia coli O157:H7 on Alfalfa Seeds

2007 ◽  
Vol 70 (7) ◽  
pp. 1698-1703 ◽  
Author(s):  
GUOPING FENG ◽  
JOHN J. CHUREY ◽  
RANDY W. WOROBO
Keyword(s):  
Escherichia Coli ◽  
Heat Treatment ◽  
Thermal Inactivation ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Dry Heat ◽  
Sprouted Seeds ◽  
Alfalfa Sprouts ◽  
Alfalfa Seeds

Alfalfa seeds inoculated with five strains of Salmonella or Escherichia coli O157:H7 were subjected to dry heat at 55°C for up to 8 days. Five-log reductions in Salmonella or E. coli O157:H7 on seeds were observed. No pathogens were detected on the sprouted seeds, which were initially inoculated with ca. 2 log CFU/g of Salmonella or more than 8 log CFU/g of E. coli O157:H7. The percentages of germination of the alfalfa seeds did not significantly decrease after 6 days of heating at 55°C. These results showed that heat treatment of alfalfa seeds at 55°C for up to 6 days was effective in enhancing the safety of alfalfa sprouts without affecting germination significantly.

Fates of Seeded Escherichia coli O157:H7 and Salmonella on Selected Fresh Culinary Herbs during Refrigerated Storage

2006 ◽  
Vol 69 (8) ◽  
pp. 1997-2001 ◽  
Author(s):  
WEI-YEA HSU ◽  
AMARAT SIMONNE ◽  
PONGPHEN JITAREERAT
Keyword(s):  
Escherichia Coli ◽  
Normal Distribution ◽  
Storage Time ◽  
Bacterial Pathogens ◽  
Microbial Populations ◽  
Escherichia Coli O157 ◽  
Refrigerated Storage ◽  
E Coli ◽  
Test Conditions ◽  
Culinary Herbs

The fates of seeded Escherichia coli O157:H7 and Salmonella on selected fresh culinary herbs were evaluated at a refrigerated temperature (4°C). Fresh herbs, including cilantro, oregano, basil, chive, parsley, and rosemary, were inoculated with six-strain mixtures of E. coli O157:H7 and Salmonella, and the microbial populations were monitored at 1, 5, 11, 16, 19, and 24 days. For both pathogens, a significant decrease in the population (P < 0.0001) occurred within the first 5 days of storage (<0.8 log). Both pathogens remained the highest on cilantro and the lowest on rosemary (P < 0.0001). Storage time had a significant effect on the survival of E. coli O157:H7; populations declined as storage time progressed. Although storage of cilantro, basil, and chive was terminated after 19 days because of deteriorated quality, significant numbers of both pathogens were recovered from the remaining fresh herbs after 24 days of storage. The results showed that both bacteria were extremely persistent on all test herbs under the test conditions. The results also reinforce the concept that, once contaminated, bacterial pathogens can persist on fresh herbs throughout a normal distribution time.

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