Residues of five pesticides in field‐treated alfalfa seeds and alfalfa sprouts

1985 ◽  
Vol 20 (4) ◽  
pp. 445-456 ◽  
Author(s):  
T.E. Archer ◽  
W.O. Gauer
Keyword(s):  
Alfalfa Sprouts ◽  
Alfalfa Seeds

Effects of Community Versus Single Strain Inoculants on the Biocontrol of Salmonella and Microbial Community Dynamics in Alfalfa Sprouts†

2005 ◽  
Vol 68 (1) ◽  
pp. 40-48 ◽  
Author(s):  
ANABELLE MATOS ◽  
JAY L. GARLAND
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Community Dynamics ◽  
Community Level ◽  
Microbial Consortia ◽  
Single Strain ◽  
Acridine Orange Staining ◽  
Physiological Profiles ◽  
Alfalfa Sprouts ◽  
Alfalfa Seeds

Potential biological control inoculants, Pseudomonas fluorescens 2-79 and microbial communities derived from market sprouts or laboratory-grown alfalfa sprouts, were introduced into alfalfa seeds with and without a Salmonella inoculum. We examined their ability to inhibit the growth of this foodborne pathogen and assess the relative effects of the inoculants on the alfalfa microbial community structure and function. Alfalfa seeds contaminated with a Salmonella cocktail were soaked for 2 h in bacterial suspensions from each inoculant tested. Inoculated alfalfa seeds were grown for 7 days and sampled during days 1, 3, and 7. At each sampling, alfalfa sprouts were sonicated for 7 min to recover microflora from the surface, and the resulting suspensions were diluted and plated on selective and nonselective media. Total bacterial counts were obtained using acridine orange staining, and the percentage culturability was calculated. Phenotypic potential of sprout-associated microbial communities inoculated with biocontrol treatments was assessed using community-level physiological profiles based on patterns of use of 95 separate carbon sources in Biolog plates. Community-level physiological profiles were also determined using oxygen-sensitive fluorophore in BD microtiter plates to examine functional patterns in these communities. No significant differences in total and mesophilic aerobe microbial cell density or microbial richness resulting from the introduction of inoculants on alfalfa seeds with and without Salmonella were observed. P. fluorescens 2-79 exhibited the greatest reduction in the growth of Salmonella early during alfalfa growth (4.22 log at day 1), while the market sprout inoculum had the reverse effect, resulting in a maximum log reduction (5.48) of Salmonella on day 7. Community-level physiological profiles analyses revealed that market sprout communities peaked higher and faster compared with the other inoculants tested. These results suggest that different modes of actions of single versus microbial consortia biocontrol treatments may be involved.

Comparison of Aqueous Chemical Treatments To Eliminate Salmonella on Alfalfa Seeds

2000 ◽  
Vol 63 (11) ◽  
pp. 1475-1482 ◽  
Author(s):  
W. R. WEISSINGER ◽  
L. R. BEUCHAT
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
Tween 80 ◽  
The United States ◽  
Germination Percentage ◽  
Minimal Effect ◽  
Direct Plating ◽  
Chemical Treatments ◽  
Alfalfa Sprouts ◽  
Alfalfa Seeds

Several outbreaks of salmonellosis associated with alfalfa sprouts have been documented in the United States since 1995. This study was undertaken to evaluate various chemical treatments for their effectiveness in killing Salmonella on alfalfa seeds. Immersing inoculated seeds in solutions containing 20,000 ppm free chlorine (Ca[OCl]2), 5% Na3PO4, 8% H2O2, 1% Ca(OH)2, 1% calcinated calcium, 5% lactic acid, or 5% citric acid for 10 min resulted in reductions of 2.0 to 3.2 log10 CFU/g. Treatment with 1,060 ppm Tsunami or Vortex, 1,200 ppm acidified NaClO2, or 5% acetic acid were less effective in reducing Salmonella populations. With the exceptions of 8% H2O2, 1% Ca(OH)2, and 1% calcinated calcium that reduced populations by 3.2, 2.8, and 2.9 log10 CFU/g, respectively, none of treatments reduced the number of Salmonella by more than 2.2 log10 CFU/g without significantly reducing the seed germination percentage. Treatment with 5% acetic, lactic, or citric acids substantially reduced the ability of seeds to germinate. Treatment with 1% Ca(OH)2 in combination with 1% Tween 80, a surfactant, enhanced inactivation by 1.3 log10 CFU/g compared to treatment with 1% Ca(OH)2 alone. Presoaking seeds in water, 0.1% EDTA, 1% Tween 80, or 1% Tween 80 plus 0.1% EDTA for 30 min before treatment with water, 2,000 ppm NaOCl, or 2% lactic acid had a minimal effect on reducing populations of Salmonella. Results indicate that, although several chemical treatments cause reductions in Salmonella populations of up to 3.2 log10 CFU/g initially on alfalfa seeds when analyzed by direct plating, no treatment eliminated the pathogen, as evidenced by detection in enriched samples.

scholarly journals Differences in Growth of Salmonella enterica and Escherichia coli O157:H7 on Alfalfa Sprouts

2002 ◽  
Vol 68 (6) ◽  
pp. 3114-3120 ◽  
Author(s):  
A. O. Charkowski ◽  
J. D. Barak ◽  
C. Z. Sarreal ◽  
R. E. Mandrell
Keyword(s):  
Escherichia Coli ◽  
Irrigation Water ◽  
Salmonella Enterica ◽  
Fluorescent Protein ◽  
Human Pathogens ◽  
E Coli ◽  
Inoculum Dose ◽  
Alfalfa Sprouts ◽  
Green Fluorescent ◽  
Alfalfa Seeds

ABSTRACT Sprout producers have recently been faced with several Salmonella enterica and Escherichia coli O157:H7 outbreaks. Many of the outbreaks have been traced to sprout seeds contaminated with low levels of human pathogens. Alfalfa seeds were inoculated with S. enterica and E. coli O157:H7 strains isolated from alfalfa seeds or other environmental sources and sprouted to examine growth of these human pathogens in association with sprouting seeds. S. enterica strains grew an average of 3.7 log10 on sprouting seeds over 2 days, while E. coli O157:H7 strains grew significantly less, an average of 2.3 log10. The initial S. enterica or E. coli O157:H7 inoculum dose and seed-sprouting temperature significantly affected the levels of both S. enterica and E. coli O157:H7 on the sprouts and in the irrigation water, while the frequency of irrigation water replacement affected only the levels of E. coli O157:H7. Colonization of sprouting alfalfa seeds by S. enterica serovar Newport and E. coli O157:H7 strains transformed with a plasmid encoding the green fluorescent protein was examined with fluorescence microscopy. Salmonella serovar Newport colonized both seed coats and sprout roots as aggregates, while E. coli O157:H7 colonized only sprout roots.

scholarly journals The Evaluation of Antibacterial Activity of Copper Sheets in the Germination of Alfalfa Seeds (Medicago sativa L.) within a Rotating Drum

2020 ◽  
Vol 8 (4) ◽  
Author(s):  
José F. Reyes ◽  
Johannes P.F. De Bruijn ◽  
Guillermo F. Tolosa ◽  
Pedro M. Aqueveque ◽  
Christian L. Correa
Keyword(s):  
Antibacterial Activity ◽  
Medicago Sativa ◽  
Quality Parameters ◽  
Rotating Drum ◽  
Mass Unit ◽  
E Coli ◽  
Calcium Magnesium ◽  
Alfalfa Sprouts ◽  
Iron Manganese ◽  
Alfalfa Seeds

— The consumption of sprouts in the human diet has grown during the last years, but great concern raised from public health institutions, food industry and consumers regarding their safety since foodborne diseases caused by microorganisms have been reported. Copper metal as a contact surface was studied during the germination of alfalfa seeds (Medicago sativa L.) inside a rotating drum on a laboratory scale and compared with a plastic surface of food-grade. A system of three rotating drums was used inside a thermo-regulated chamber to germinate seeds. To evaluate the antibacterial activity of copper sheets, alfalfa seeds were inoculated with 4.2 log cfu g-1 of Escherichia coli and after 84 hours of germination sprouts were evaluated for E. coli, mesophilic aerobic bacteria, the content of copper and other minerals (potassium, calcium, magnesium, sodium, iron, manganese, and zinc), total mass, unit mass and length, and color. The contact of alfalfa sprouts with copper sheets allowed to reduce the E. coli load from 6.54 to <0.1 log cfu g-1. However, all sprouts exceeded in copper (> 10 ppm) according to Food Sanitary Regulations. Germinated mass and length decreased after copper treatments. No statistically significant differences were observed between treatments for the remaining quality parameters. Finally, it is concluded that copper was very efficient in reducing the microbial load of E. coli in alfalfa sprouts, complying with the regulations established by the Chilean Ministry of Health.

Effect of Hydrogen Peroxide Pretreatment on Physiological and Biochemical Variables during Germination of Alfalfa Seeds

2021 ◽  
Author(s):  
F. Muñoz-Salinas ◽  
E.G. Tovar-Pérez ◽  
R.G. Guevara-González ◽  
G.F. Loarca-Piña ◽  
Irineo Torres-Pacheco
Keyword(s):  
Hydrogen Peroxide ◽  
Antioxidant Properties ◽  
Biotic And Abiotic Stress ◽  
Biochemical Effects ◽  
Unpredictable Environments ◽  
Animal Feeding ◽  
Medicago Sativa L ◽  
Alfalfa Sprouts ◽  
Physiological And Biochemical ◽  
Alfalfa Seeds

Background: Hydrogen peroxide is reactive oxygen species that plays role in plant response to biotic and abiotic stress. The pretreatment with hydrogen peroxide can confer an adaptive capacity for the plants in unpredictable environments. The alfalfa (Medicago sativa L.) is the legume more utilized in animal feeding in the world. Moreover, the alfalfa sprouts are known for the phytochemicals that promote health with antioxidant properties. Methods: This work aimed to determine the effect of hydrogen peroxide in the pretreatment process of alfalfa seeds on variables as total germination, speed of germination, activity and antioxidant enzymes. The alfalfa seeds were soaked for 12 h in the next treatments 0, 98, 294, 490, 784, 980 mM of hydrogen peroxide. Result: The results showed that total germination was higher with the hydrogen peroxide than with water except 980 mM. The results of the present research indicated that hydrogen peroxide had physiological and biochemical effects on the germination processes of alfalfa.

Evaluation of Volatile Chemical Treatments for Lethality to Salmonella on Alfalfa Seeds and Sprouts

2001 ◽  
Vol 64 (4) ◽  
pp. 442-450 ◽  
Author(s):  
W. R. WEISSINGER ◽  
K. H. McWATTERS ◽  
L. R. BEUCHAT
Keyword(s):  
Acetic Acid ◽  
Sensory Quality ◽  
Allyl Isothiocyanate ◽  
Germination Percentage ◽  
Initial Population ◽  
Cinnamic Aldehyde ◽  
Control Seed ◽  
Chemical Treatments ◽  
Alfalfa Sprouts ◽  
Alfalfa Seeds

A study was done to evaluate natural volatile compounds for their ability to kill Salmonella on alfalfa seeds and sprouts. Acetic acid, allyl isothiocyanate (AIT), trans-anethole, carvacrol, cinnamic aldehyde, eugenol, linalool, methyl jasmonate, and thymol were examined for inhibitory and lethal activity against Salmonella by exposing inoculated alfalfa seeds to compounds (1,000 mg/liter of air) for 1, 3, and 7 h at 60°C. Only acetic acid, cinnamic aldehyde, and thymol caused significant reductions in Salmonella populations (&gt;3 log10 CFU/g) compared with the control (1.9 log10 CFU/g) after treatment for 7 h. Treatment of seeds at 50°C for 12 h with acetic acid (100 and 300 mg/liter of air) and thymol or cinnamic aldehyde (600 mg/liter of air) significantly reduced Salmonella populations on seeds (&gt;1.7 log10 CFU/g) without affecting germination percentage. Treatment of seeds at 50°C with AIT (100 and 300 mg/liter of air) and cinnamic aldehyde or thymol (200 mg/liter of air) did not significantly reduce populations compared with the control. Seed germination percentage was largely unaffected by treatment with gaseous acetic acid, AIT, cinnamic aldehyde, or thymol for up to 12 h at 50°C. The number of Salmonella on seeds treated at 70°C for 80 min with acetic acid (100 and 300 mg/liter of air), AIT (100 mg/liter of air), and cinnamic aldehyde and thymol (600 mg/liter of air) at water activity (aw) 0.66 was not significantly different than the number inactivated on seeds at aw 0.49. Acetic acid at 200 and 500 mg/liter of air reduced an initial population of 7.50 log10 CFU/g of alfalfa sprouts by 2.33 and 5.72 log10 CFU/g, respectively, within 4 days at 10°C, whereas AIT at 200 and 500 mg/liter of air reduced populations to undetectable levels; however, both treatments caused deterioration in sensory quality. Treatment of sprouts with 1 or 2 mg of AIT per liter of air adversely affected sensory quality but did not reduce Salmonella populations after 11 days of exposure at 10°C.

Behavior of Non-O157 Shiga Toxin–Producing Escherichia coli, Enteroinvasive E. coli, Enteropathogenic E. coli, and Enterotoxigenic E. coli Strains on Alfalfa Sprouts

2013 ◽  
Vol 76 (8) ◽  
pp. 1429-1433 ◽  
Author(s):  
CARLOS A. GÓMEZ-ALDAPA ◽  
ESMERALDA RANGEL-VARGAS ◽  
M. del REFUGIO TORRES-VITELA ◽  
ANGÉLICA VILLARRUEL-LÓPEZ ◽  
JAVIER CASTRO-ROSAS
Keyword(s):  
Escherichia Coli ◽  
Seed Germination ◽  
Shiga Toxin ◽  
Practical Significance ◽  
E Coli ◽  
Alfalfa Sprouts ◽  
Alfalfa Seeds

Data about the behavior of non-O157 Shiga toxin–producing Escherichia coli (non-O157 STEC), enteroinvasive E. coli (EIEC), enterotoxigenic E. coli (ETEC), and enteropathogenic E. coli (EPEC) on seeds and alfalfa sprouts are not available. The behavior of STEC, EIEC, ETEC, and EPEC was determined during germination and sprouting of alfalfa seeds at 20 ± 2°C and 30 ± 2°C and on alfalfa sprouts at 3 ± 2°C. When alfalfa seeds were inoculated with STEC, EIEC, ETEC, or EPEC strains, all these diarrheagenic E. coli pathotypes (DEPs) grew during germination and sprouting of seeds, reaching counts of approximately 5 and 6 log CFU/g after 1 day at 20 ± 2°C and 30 ± 2°C, respectively. However, when the sprouts were inoculated after 1 day of seed germination and stored at 20 ± 2°Cor30 ± 2°C, no growth was observed for any DEP during sprouting at 20 ± 2°Cor 30 ± 2°C for 9 days. Refrigeration reduced significantly (P &lt; 0.0.5) the number of viable DEPs on sprouts after 20 days in storage; nevertheless, these decreases have no practical significance for the safety of the sprouts.

Inactivation of Human Norovirus and Its Surrogates on Alfalfa Seeds by Aqueous Ozone

2015 ◽  
Vol 78 (8) ◽  
pp. 1586-1591 ◽  
Author(s):  
QING WANG ◽  
SARAH MARKLAND ◽  
KALMIA E. KNIEL
Keyword(s):  
Deionized Water ◽  
Murine Norovirus ◽  
Food Matrix ◽  
Human Norovirus ◽  
Viral Genomes ◽  
Tulane Virus ◽  
Foodborne Outbreaks ◽  
Alfalfa Sprouts ◽  
All Treatment ◽  
Alfalfa Seeds

Alfalfa sprouts have been associated with numerous foodborne outbreaks. Previous studies investigated the effectiveness of aqueous ozone on bacterially contaminated seeds, yet little is known about the response of human norovirus (huNoV). This study assessed aqueous ozone for the disinfection of alfalfa seeds contaminated with huNoV and its surrogates. The inactivation of viruses without a food matrix was also investigated. Alfalfa seeds were inoculated with huNoV genogroup II, Tulane virus (TV), and murine norovirus (MNV); viruses alone or inoculated on seeds were treated in deionized water containing 6.25 ppm of aqueous ozone with agitation at 22°C for 0.5, 1, 5, 15, or 30 min. The data showed that aqueous ozone resulted in reductions of MNV and TV infectivity from 1.66 ± 1.11 to 5.60 ± 1.11 log PFU/g seeds; for all treatment times, significantly higher reductions were observed for MNV (P &lt; 0.05). Viral genomes were relatively resistant, with a reduction of 1.50 ± 0.14 to 3.00 ± 0.14 log genomic copies/g seeds; the reduction of TV inoculated in water was similar to that of huNoV, whereas MNV had significantly greater reductions in genomic copies (P &lt; 0.05). Similar trends were observed in ozone-treated viruses alone, with significantly higher levels of inactivation (P &lt; 0.05), especially with reduced levels of infectivity for MNV and TV. The significant inactivation by aqueous ozone indicates that ozone may be a plausible substitute for chlorine as an alternative treatment for seeds. The behavior of TV was similar to that of huNoV, which makes it a promising surrogate for these types of scenarios.

scholarly journals Growth Dynamics of Salmonella enterica Strains on Alfalfa Sprouts and in Waste Seed Irrigation Water

2003 ◽  
Vol 69 (1) ◽  
pp. 548-553 ◽  
Author(s):  
Michael B. Howard ◽  
Steven W. Hutcheson
Keyword(s):  
Seed Germination ◽  
Irrigation Water ◽  
Salmonella Enterica ◽  
Meat Products ◽  
Growth Dynamics ◽  
Strongly Correlated ◽  
Germination Process ◽  
Alfalfa Sprouts ◽  
Clinically Significant ◽  
Alfalfa Seeds

ABSTRACT Alfalfa sprouts and other seed sprouts have been implicated in numerous outbreaks of salmonellosis. The source of these epidemics appears to have been low-level contamination of seeds by Salmonella bacteria that developed into clinically significant populations during the seed germination process. To test the possibility that Salmonella enterica strains carry host range determinants that allow them to grow on alfalfa, strains isolated from alfalfa or other sources were surveyed for their ability to grow on germinating alfalfa seeds. An S. enterica serovar Cubana strain originally isolated from contaminated alfalfa sprouts multiplied most rapidly during the initial 24 h of the seed germination process. Germinating alfalfa seeds supported the multiplication of S. enterica cells prior to the emergence of the root radicle at 72 h. Thereafter, much lower rates of multiplication were apparent. The ability of S. enterica to grow on germinating alfalfa seeds was independent of the serovar, isolation source, or virulence of the strain. Isolates obtained from alfalfa attained population levels similar to those observed for strains isolated from contaminated meat products or stools. Each of the strains could be detected in the waste irrigation water, with populations being strongly correlated with those detected on the germinating alfalfa seeds. The S. enterica strains were capable of utilizing the waste irrigation water as a sole carbon and nitrogen source. S. enterica strains thus appear to grow saprophytically on soluble organics released from seeds during early phases of germination. The ability to detect S. enterica in the waste irrigation water early in the germination process indicates that this method may be used as a simple way to monitor the contamination of sprouts during commercial operations.

Use of Green Fluorescent Protein Expressing Salmonella Stanley To Investigate Survival, Spatial Location, and Control on Alfalfa Sprouts

2001 ◽  
Vol 64 (12) ◽  
pp. 1891-1898 ◽  
Author(s):  
MEGHA GANDHI ◽  
SHERENE GOLDING ◽  
SIMA YARON ◽  
KARL R. MATTHEWS
Keyword(s):  
Green Fluorescent Protein ◽  
Laser Scanning ◽  
Fluorescent Protein ◽  
Plasmid Stability ◽  
Constitutive Expression ◽  
Epifluorescence Microscopy ◽  
Initial Population ◽  
Alfalfa Sprouts ◽  
Green Fluorescent ◽  
Alfalfa Seeds

Laser scanning confocal microscopy (LSCM) was used to observe the interaction of Salmonella Stanley with alfalfa sprouts. The green fluorescent protein (gfp) gene was integrated into the chromosome of Salmonella Stanley for constitutive expression, thereby eliminating problems of plasmid stability and loss of signal. Alfalfa seeds were inoculated by immersion in a suspension of Salmonella Stanley (ca. 107 CFU/ml) for 5 min at 22°C. Epifluorescence microscopy demonstrated the presence of target bacteria on the surface of sprouts. LSCM demonstrated bacteria present at a depth of 12μm within intact sprout tissue. An initial population of ca. 104 CFU/g seed increased to 7.0 log CFU/g during a 24-h germination period and then decreased to 4.9 log CFU/g during a 144-h sprouting period. Populations of Salmonella Stanley on alfalfa seeds decreased from 5.2 to 4.1 log CFU/g and from 5.2 to 2.8 log CFU/g for seeds stored 60 days at 5 and 22°C, respectively. The efficacy of 100, 200, 500, or 2,000 ppm chlorine in killing Salmonella Stanley associated with sprouts was determined. Treatment of sprouts in 2,000 ppm chlorine for 2 or 5 min caused a significant reduction in populations of Salmonella Stanley. Influence of storage on Salmonella Stanley populations was investigated by storing sprouts 4 days at 4°C. The initial population (7.76 log CFU/g) of Salmonella Stanley on mature sprouts decreased (7.67 log CFU/g) only slightly. Cross-contamination during harvest was investigated by harvesting contaminated sprouts, then directly harvesting noncontaminated sprouts. This process resulted in the transfer of ca. 105 CFU/g Salmonella Stanley to the noncontaminated sprouts.

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