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.

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.

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 < 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.

Reduction of Salmonella enterica on Alfalfa Seeds with Acidic Electrolyzed Oxidizing Water and Enhanced Uptake of Acidic Electrolyzed Oxidizing Water into Seeds by Gas Exchange

2003 ◽  
Vol 66 (11) ◽  
pp. 2017-2022 ◽  
Author(s):  
SILVIA D. STAN ◽  
MARK A. DAESCHEL
Keyword(s):  
Salmonella Enterica ◽  
Antimicrobial Effect ◽  
Aqueous System ◽  
Gas Composition ◽  
Optimum Ratio ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Water Ph ◽  
Alfalfa Sprouts ◽  
Alfalfa Seeds

Alfalfa sprouts have been implicated in several salmonellosis outbreaks in recent years. The disinfectant effects of acidic electrolyzed oxidizing (EO) water against Salmonella enterica both in an aqueous system and on artificially contaminated alfalfa seeds were determined. The optimum ratio of seeds to EO water was determined in order to maximize the antimicrobial effect of EO water. Seeds were combined with EO water at ratios (wt/vol) of 1:4, 1:10, 1:20, 1:40, and 1:100, and the characteristics of EO water (pH, oxidation reduction potential [ORP], and free chlorine concentration)were determined. When the ratio of seeds to EO water was increased from 1:4 to 1:100, the pH decreased from 3.82 to 2.63, while the ORP increased from +455 to +1,073 mV. EO water (with a pH of 2.54 to 2.38 and an ORP of +1,083 to +1,092 mV) exhibited strong potential for the inactivation of S. enterica in an aqueous system (producing a reduction of at least 6.6 log CFU/ml). Treatment of artificially contaminated alfalfa seeds with EO water at a seed–to–EO water ratio of 1:100 for 15 and 60 min significantly reduced Salmonella populations by 2.04 and 1.96 log CFU/g, respectively (P < 0.05), while a Butterfield's buffer wash decreased Salmonella populations by 0.18 and 0.23 log CFU/g, respectively. After treatment, EO water was Salmonella negative by enrichment with or without neutralization. Germination of seeds was not significantly affected (P > 0.05) by treatment for up to 60 min in electrolyzed water. The uptake of liquid into the seeds was influenced by the internal gas composition (air, N2, or O2) of seeds before the liquid was added.

Evaluation of PCR Detection of Salmonella in Alfalfa Sprouts and Spent Irrigation Water Collected during Sprouting of Naturally Contaminated Seed

2013 ◽  
Vol 76 (2) ◽  
pp. 314-317 ◽  
Author(s):  
NICOLE MAKS ◽  
TONG-JEN FU
Keyword(s):  
Irrigation Water ◽  
Pcr Detection ◽  
Most Probable Number ◽  
Probable Number ◽  
Peptone Water ◽  
Low Levels ◽  
Alfalfa Sprouts ◽  
The U.S ◽  
Alfalfa Seeds

This study evaluated the efficacy of a PCR-based system (DuPont Qualicon BAX) for detection of Salmonella in sprouts and spent irrigation water collected during sprouting of seeds naturally contaminated with Salmonella. Alfalfa seeds were grown in Mason jars at 20 and 30°C for 3 days. Levels of Salmonella present in the water and sprouts were determined by most-probable-number (MPN) analysis. Background microflora levels were also determined. Samples of spent irrigation water and sprouts were enriched overnight individually in tetrathionate broth and in buffered peptone water with novobiocin at 42°C and then run in the BAX system. Samples were also enriched according to the U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA BAM) method for Salmonella as a comparison. Salmonella levels were lower at 20°C compared with 30°C for some trials, and background microflora levels ranged from 107 to 108 CFU/g or ml at 20°C and 108 to 109 CFU/g or ml at 30°C. In trials with a Salmonella level >1.1 MPN/g or ml, both the BAX and FDA BAM methods were able to detect Salmonella in all samples. In trials with lower levels (0.21 MPN/g or ml or lower) of Salmonella, BAX was able to detect more positive samples than FDA BAM. For one trial with <0.003 MPN/g or ml of Salmonella, the presence of the pathogen was not indicated by either the BAX or the FDA BAM method. The results suggest that PCR detected low levels of Salmonella in sprouts or spent irrigation water collected from sprouting of naturally contaminated seeds.

Characterisation of Salmonella enterica clones carrying mcr-1 plasmids in meat products and patients in Northern Thailand using long read sequencing

2021 ◽  
pp. 109314
Author(s):  
Prapas Patchanee ◽  
Nipa Chokesajjawatee ◽  
Pannita Santiyanont ◽  
Phongsakorn Chuammitri ◽  
Manu Deeudom ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Meat Products ◽  
Northern Thailand ◽  
Long Read

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.

Analysis of Bone Age Data From National Cooperative Growth Study Substudy VII

PEDIATRICS ◽  
1999 ◽  
Vol 104 (Supplement_5) ◽  
pp. 1031-1036
Author(s):  
Stephen F. Kemp ◽  
Judy P. Sy
Keyword(s):  
Age Determination ◽  
Bone Age ◽  
Strongly Correlated ◽  
Growth Study ◽  
Gh Therapy ◽  
Pubertal Stage ◽  
Significant Difference ◽  
Clinically Significant ◽  
National Cooperative ◽  
Age Determinations

National Cooperative Growth Study substudy VII was conducted 1) to compare standardized hand–wrist and knee bone age determinations in pubertal children treated with growth hormone (GH); 2) to compare local determinations of bone ages with centrally determined bone ages; 3) to relate the response to GH therapy to the bone age determinations; and 4) to ascertain the predictive value of each type of bone age determination. Eligible subjects were those in the National Cooperative Growth Study who were at Tanner pubertal stage 2 or greater for breasts (girls) or genitals (boys). Radiographs of the hand–wrist were taken annually, and radiographs of the knee were taken at the beginning and the end of the study. Separate bone age determinations were made from these radiographs. A combined hand–wrist and knee bone age determination also was derived. There were 990 patients in the study; in 925 (677 boys), there were both hand–wrist and knee bone age determinations from the baseline pubertal radiographs. There was only one radiographic assessment in 496 patients, two in 205 patients, and three to eight in the remaining patients. The strongest correlation was between the hand–wrist bone age and the hand–wrist plus knee bone age (r = .995). Also strongly correlated were knee with hand–wrist (r = .872) and knee with hand–wrist plus knee (r = .914). For none of these bone age methods was any statistically significant difference found between the methods. The locally determined bone ages correlated strongly with the centrally determined bone ages for knee (r = .850), hand–wrist (r = .928), and hand–wrist plus knee (r = .930); however, the locally determined knee and hand–wrist values were less (by ∼0.3 year) than the centrally determined values. These differences, however, do not appear to be clinically significant.

Use of Spent Irrigation Water for Microbiological Analysis of Alfalfa Sprouts

2001 ◽  
Vol 64 (6) ◽  
pp. 802-806 ◽  
Author(s):  
T. FU ◽  
D. STEWART ◽  
K. REINEKE ◽  
J. ULASZEK ◽  
J. SCHLESSER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Irrigation Water ◽  
Foodborne Illness ◽  
Microbiological Analysis ◽  
Escherichia Coli O157 ◽  
Salmonella Infection ◽  
Commercial Scale ◽  
Microbiological Testing ◽  
Rotary Drum ◽  
Alfalfa Sprouts

Numerous outbreaks of foodborne illness have been linked to the consumption of raw sprouts. Sprout producers have been advised by the Food and Drug Administration to include microbiological testing of spent irrigation water during production as part of an overall strategy to enhance the safety of sprouts. Alfalfa sprouts and irrigation water were analyzed to show the feasibility of using irrigation water for monitoring the microbiological safety of sprouts. Sprouts and water were produced and harvested from both commercial-scale (rotary drum) and consumer-scale (glass jars) equipment. Rapid increases of aerobic mesophiles occurred during the first 24 h of sprouting, with maximum levels achieved after 48 to 72 h. The counts in irrigation water were on average within approximately 1 log of their respective counts in the sprouts. Similar results were obtained for analysis of Escherichia coli O157:H7 in irrigation water and sprouts grown from artificially inoculated seeds. Testing of spent irrigation water indicated the contamination status of alfalfa sprouts grown from seeds associated with outbreaks of Salmonella infection.

Sign in / Sign up

Export Citation Format

Share Document