Effect of Sampling Time on the Total Recovery Rate of AGI - 30 Impingers for E. coli Aerosols

Abstract Recovery of metals from chromated copper arsenate (CCA)-treated southern pine wood particles was investigated by extraction in a microwave reactor with binary combinations of acetic acid (AA), oxalic acid (OxA), and phosphoric acid (PhA). Use of OxA was not successful, as insoluble copper oxalate complexes impeded copper removal. The combination of OxA and AA also had adverse effects on copper extraction. In contrast, the combination of AA and PhA enhanced the chromium recovery rate. The highest recovery rate of metals could be achieved with a mixture of 2.75% PhA and 0.5% AA at 130°C for 10 min in the microwave oven. The total recovery rate approached 100% for arsenic, 96.7% for chromium, and 98.6% for copper in a one-step process.

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Changes in Aerobic Plate and Escherichia coli–Coliform Counts and in Populations of Inoculated Foodborne Pathogens on Inshell Walnuts during Storage

Journal of Food Protection ◽

10.4315/0362-028x.jfp-15-553 ◽

2016 ◽

Vol 79 (7) ◽

pp. 1143-1153 ◽

Cited By ~ 8

Author(s):

JOHN C. FRELKA ◽

GORDON R. DAVIDSON ◽

LINDA J. HARRIS

Keyword(s):

Escherichia Coli ◽

Listeria Monocytogenes ◽

Relative Humidity ◽

Low Temperature ◽

Foodborne Pathogens ◽

Limit Of Detection ◽

Sampling Time ◽

E Coli ◽

Plate Counts ◽

Forced Air

ABSTRACT After harvest, inshell walnuts are dried using low-temperature forced air and are then stored in bins or silos for up to 1 year. To better understand the survival of bacteria on inshell walnuts, aerobic plate counts (APCs) and Escherichia coli–coliform counts (ECCs) were evaluated during commercial storage (10 to 12°C and 63 to 65% relative humidity) over 9 months. APCs decreased by 1.4 to 2.0 log CFU per nut during the first 5 months of storage, and ECCs decreased by 1.3 to 2.2 log CFU per nut in the first month of storage. Through the remaining 4 to 8 months of storage, APCs and ECCs remained unchanged (P > 0.05) or decreased by <0.15 log CFU per nut per month. Similar trends were observed on kernels extracted from the inshell walnuts. APCs and ECCs were consistently and often significantly higher on kernels extracted from visibly broken inshell walnuts than on kernels extracted from visibly intact inshell walnuts. Parameters measured in this study were used to determine the survival of five-strain cocktails of E. coli O157:H7, Listeria monocytogenes, and Salmonella inoculated onto freshly hulled inshell walnuts (~8 log CFU/g) after simulated commercial drying (10 to 12 h; 40°C) and simulated commercial storage (12 months at 10°C and 65% relative humidity). Populations declined by 2.86, 5.01, and 4.40 log CFU per nut for E. coli O157:H7, L. monocytogenes, and Salmonella, respectively, after drying and during the first 8 days of storage. Salmonella populations changed at a rate of −0.33 log CFU per nut per month between days 8 and 360, to final levels of 2.83 ± 0.79 log CFU per nut. E. coli and L. monocytogenes populations changed by −0.17 log CFU per nut per month and −0.26 log CFU per nut per month between days 8 and 360, respectively. For some samples, E. coli or L. monocytogenes populations were below the limit of detection by plating (0.60 log CFU per nut) by day 183 or 148, respectively; at least one of the six samples was positive at each subsequent sampling time by either plating or by enrichment.

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Hollow-Fiber Ultrafiltration for the Concentration and Simultaneous Recovery of Multiple Pathogens in Contaminated Foods

Journal of Food Protection ◽

10.4315/0362-028x-72.12.2547 ◽

2009 ◽

Vol 72 (12) ◽

pp. 2547-2552 ◽

Cited By ~ 11

Author(s):

HEE-YEON KIM ◽

HYEUN-JIN PARK ◽

GWANGPYO KO

Keyword(s):

Hollow Fiber ◽

Food Samples ◽

Murine Norovirus ◽

Viral Pathogens ◽

Recovery Rates ◽

Total Recovery ◽

E Coli ◽

Reverse Transcription Pcr ◽

Elution Buffer ◽

Multiple Pathogens

We investigated the possibility of using hollow-fiber ultrafiltration (HUF) for the simultaneous recovery of multiple microorganisms in food samples. MS2 bacteriophage, E. coli, Bacillus subtilis spores, and murine norovirus (MNV) were each inoculated into 5 liters of either distilled water (DW) or glycine elution buffer and then concentrated using hollow-fiber polysulfone ultrafilters. The resulting concentrates were further analyzed by either cultivation or TaqMan real-time reverse transcription PCR assay. The overall average recovery rates were 7.1% in DW and 17.1% in glycine elution buffer. When the virus, vegetative bacteria, and bacterial spores were simultaneously inoculated into DW, glycine, or Tris-HCl elution buffers, on average 16.8% of inoculated microorganisms were recovered by HUF. The addition of 3% beef extract blocking buffer to HUF increased the total recovery rate to 46.1%, with incremental recovery rates increasing sharply for B. subtilis spores and MNV. Use of HUF resulted in E. coli recovery rates of 68.0% on lettuce and 66.2% on ham and MNV recovery rates of 1.5% on lettuce and 5.8% on ham. Our study demonstrates that HUF can be effective at simultaneously recovering and concentrating diverse bacterial and viral pathogens from foods.

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Comparison of Two Sampling Methods for Escherichia coli O157:H7 Detection in Feedlot Cattle

Journal of Food Protection ◽

10.4315/0362-028x-68.8.1724 ◽

2005 ◽

Vol 68 (8) ◽

pp. 1724-1728 ◽

Cited By ~ 14

Author(s):

M. L. KHAITSA ◽

M. L. BAUER ◽

P. S. GIBBS ◽

G. P. LARDY ◽

D. DOETKOTT ◽

...

Keyword(s):

Escherichia Coli ◽

Sampling Methods ◽

Feedlot Cattle ◽

Sampling Time ◽

Escherichia Coli O157 ◽

Confounding Factors ◽

Rank Tests ◽

E Coli ◽

Signed Rank ◽

Sampling Times

Two sampling methods (rectoanal swabs and rectal fecal grabs) were compared for their recovery of Escherichia coli O157:H7 from feedlot cattle. Samples were collected from 144 steers four times during the finishing period by swabbing the rectoanal mucosa with cotton swabs and immediately obtaining feces from the rectum of each individual steer. The number of steers with detectable E. coli O157:H7 increased from 2 of 144 (1.4%) cattle on arrival at the feedlot to 10 of 144 (6.9%) after 1 month, 76 of 143 (52.8%) after 7 months, and 30 of 143 (20.8%) at the last sampling time before slaughter. Wilcoxon signed-rank tests indicated that the two sampling methods gave different results for sampling times 3 and 4 (P < 0.05) but not for sampling time 2 (P = 0.16). Agreement between the two sampling methods was poor (kappa < 0.2) for three of the four sampling times and moderate (kappa = 0.6) for one sampling time, an indication that in this study rectoanal swabs usually were less sensitive than rectal fecal grabs for detection of E. coli O157:H7 in cattle. Overall, the herd of origin was not significantly associated with E. coli O157:H7 results, but the weight of the steers was. Further investigation is needed to determine the effects of potential confounding factors (e.g., size and type of swab, consistency of feces, site sampled, and swabbing technique) that might influence the sensitivity of swabs in recovering E. coli O157:H7 from the rectoanal mucosa of cattle.

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Hydrogenetic, Diagenetic and Hydrothermal Processes Forming Ferromanganese Crusts in the Canary Island Seamounts and Their Influence in the Metal Recovery Rate with Hydrometallurgical Methods

Minerals ◽

10.3390/min9070439 ◽

2019 ◽

Vol 9 (7) ◽

pp. 439 ◽

Cited By ~ 8

Author(s):

Egidio Marino ◽

Francisco Javier González ◽

Thomas Kuhn ◽

Pedro Madureira ◽

Anna V. Wegorzewski ◽

...

Keyword(s):

Canary Islands ◽

Recovery Rate ◽

Inductively Coupled Plasma ◽

Metal Recovery ◽

Critical Metals ◽

Total Recovery ◽

Inductively Coupled ◽

Ferromanganese Crusts ◽

Electron Probe Micro Analyzer ◽

Hydrometallurgical Method

Four pure hydrogenetic, mixed hydrogenetic-diagenetic and hydrogenetic-hydrothermal Fe-Mn Crusts from the Canary Islands Seamount Province have been studied by Micro X-Ray Diffraction, Raman and Fourier-transform infrared spectroscopy together with high resolution Electron Probe Micro Analyzer and Laser Ablation Inductively Coupled Plasma Mass Spectrometry in order to find the correlation of mineralogy and geochemistry with the three genetic processes and their influence in the metal recovery rate using an hydrometallurgical method. The main mineralogy and geochemistry affect the contents of the different critical metals, diagenetic influenced crusts show high Ni and Cu (up to 6 and 2 wt. %, respectively) (and less Co and REY) enriched in very bright laminae. Hydrogenetic crusts on the contrary show High Co and REY (up to 1 and 0.5 wt. %) with also high contents of Ni, Mo and V (average 2500, 600 and 1300 μg/g). Finally, the hydrothermal microlayers from crust 107-11H show their enrichment in Fe (up to 50 wt. %) and depletion in almost all the critical elements. One hydrometallurgical method has been used in Canary Islands Seamount Province crusts in order to quantify the recovery rate of valuable elements in all the studied crusts except the 107-11H, whose hydrothermal critical metals’ poor lamina were too thin to separate from the whole crust. Digestion treatment with hydrochloric acid and ethanol show a high recovery rate for Mn (between 75% and 81%) with respect to Fe (49% to 58%). The total recovery rate on valuable elements (Co, Ni, Cu, V, Mo and rare earth elements plus yttrium (REY)) for the studied crusts range between 67 and 92% with the best results for Co, Ni and V (up to 80%). The genetic process and the associated mineralogy seem to influence the recovery rate. Mixed diagenetic/hydrogenetic crust show the lower recovery rate for Mn (75%) and Ni (52.5%) both enriched in diagenetic minerals (respectively up to 40 wt. % and up to 6 wt. %). On the other hand, the presence of high contents of undigested Fe minerals (i.e., Mn-feroxyhyte) in hydrogenetic crusts give back low recovery rate for Co (63%) and Mo (42%). Finally, REY as by-product elements, are enriched in the hydrometallurgical solution with a recovery rate of 70–90% for all the studied crusts.

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A Longitudinal Study of Stuttering in Children

Journal of Speech Language and Hearing Research ◽

10.1044/jshr.3904.826 ◽

1996 ◽

Vol 39 (4) ◽

pp. 826-826 ◽

Cited By ~ 1

Author(s):

Ehud Yairi ◽

Nicoline Ambrose

Keyword(s):

Longitudinal Study ◽

Recovery Rate ◽

Preliminary Report ◽

Spontaneous Recovery ◽

Statistical Significance ◽

Treated Group ◽

Untreated Group ◽

Success Rates ◽

Total Recovery ◽

Post Onset

It has come to our attention that minor errors occurred in Table 3 on p. 759 of the Yairi and Ambrose article, "A Longitudinal Study of Stuttering in Children: A Preliminary Report," which appeared in the August 1992 issue (Vol. 35, pp. 755–760). A revised version of the table appears below that includes both the original values and the corrected values (in boldface). As can be seen, the differences are indeed minor. The changes do not affect the reported patterns or level of statistical significance. In the untreated group, 7 or 78% recovered by 24 months post-onset and 1 additional subject recovered later, making a total recovery rate of 89%, with 11% persistent. In the treated group, 11 or 61% recovered by 24 months post-onset and an additional 5 recovered later, again totalling 89% recovery and 11% persistent. These data do not in any way indicate that treatment is not beneficial nor that it has no effect but simply that success rates for treated individuals must take spontaneous recovery into account. We regret the error.

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Combined effect of chelating agents and ultrasound on biofilm removal from stainless steel surfaces. Application to “Escherichia coli milk” and “Staphylococcus aureus milk” biofilms

Biofilms ◽

10.1017/s1479050504001140 ◽

2004 ◽

Vol 1 (1) ◽

pp. 65-73 ◽

Cited By ~ 24

Author(s):

N. Oulahal ◽

A. Martial-Gros ◽

M. Bonneau ◽

L. J. Blum

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Stainless Steel ◽

Recovery Rate ◽

Combined Treatment ◽

Chelating Agent ◽

Ultrasonic Waves ◽

E Coli ◽

Closed Surfaces ◽

Biofilm Removal

Two ultrasonic devices – flat (T1) and curved (T2) ultrasonic transducers – were developed to remove biofilms from opened and closed surfaces, respectively. The aim is to standardize biofilm removal for in situ sanitary control in the food industry. The biofilms studied in this work were model biofilms made with milk on stainless steel sheets. We have shown in a previous study that sonication could be employed to remove and resuspend biofilm consistently, with a good recovery rate, from opened surfaces. Plate counting was used to assess the efficiency of each treatment. A total removal of Escherichia coli and Staphylococcus aureus from model biofilms was obtained with T1: 10 s at 40 kHz. However, ultrasound applied with T2 (a patented curved transducer developed for closed surfaces: 10 s at 40 kHz) failed to completely remove these model biofilms: 30±7% and 66±10% for E. coli and S. aureus biofilms, respectively. In order to improve the biofilm removal from closed surfaces with T2, the effect of the application of ultrasound in combination with chelating agent preparations was investigated. The application of ultrasound with T2 in 0.05 mol EDTA or EGTA per litre dislodged the E. coli milk model biofilm, with 100±10% and 100±5% recovery yields, respectively. These results showed a synergism between ultrasonic waves and chelator preparations, i.e. the combination achieved three times the recovery rate of sonication alone (30%). However, when the same treatment was applied to the S. aureus milk model biofilm, the combined treatment with EDTA or EGTA did not significantly improve the recovery of the biofilm cells: 74±26% with EDTA at 0.025 mol/l and 41–47% with EGTA at 0.025 mol/l and 0.05 mol/l, respectively, compared with 66±10% for sonication alone. The combined treatment was in agreement with an industrial control, i.e. a good reproducible recovery of the biofilm in a few seconds (10 s) for E. coli milk biofilms but not for S. aureus biofilms.

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Efficacy of Electrolyzed Oxidizing Water for Inactivating Escherichia coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes

Applied and Environmental Microbiology ◽

10.1128/aem.65.9.4276-4279.1999 ◽

1999 ◽

Vol 65 (9) ◽

pp. 4276-4279 ◽

Cited By ~ 183

Author(s):

Kumar S. Venkitanarayanan ◽

Gabriel O. Ezeike ◽

Yen-Con Hung ◽

Michael P. Doyle

Keyword(s):

Escherichia Coli ◽

Listeria Monocytogenes ◽

Salmonella Enteritidis ◽

Sampling Time ◽

Deionized Water ◽

Escherichia Coli O157 ◽

Water Control ◽

E Coli ◽

Complete Inactivation ◽

Control Samples

ABSTRACT The efficacy of electrolyzed oxidizing water for inactivatingEscherichia coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes was evaluated. A five-strain mixture of E. coli O157:H7,S. enteritidis, or L. monocytogenes of approximately 108 CFU/ml was inoculated in 9 ml of electrolyzed oxidizing water (treatment) or 9 ml of sterile, deionized water (control) and incubated at 4 or 23°C for 0, 5, 10, and 15 min; at 35°C for 0, 2, 4, and 6 min; or at 45°C for 0, 1, 3, and 5 min. The surviving population of each pathogen at each sampling time was determined on tryptic soy agar. At 4 or 23°C, an exposure time of 5 min reduced the populations of all three pathogens in the treatment samples by approximately 7 log CFU/ml, with complete inactivation by 10 min of exposure. A reduction of ≥7 log CFU/ml in the levels of the three pathogens occurred in the treatment samples incubated for 1 min at 45°C or for 2 min at 35°C. The bacterial counts of all three pathogens in control samples remained the same throughout the incubation at all four temperatures. Results indicate that electrolyzed oxidizing water may be a useful disinfectant, but appropriate applications need to be validated.

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Virulence factors and phylogenetic group profile of uterine Escherichia coli in early postpartum of high-producing dairy cows

Animal Production Science ◽

10.1071/an17729 ◽

2019 ◽

Vol 59 (10) ◽

pp. 1898

Author(s):

Luana de Cássia Bicudo ◽

Eunice Oba ◽

Sony Dimas Bicudo ◽

Domingos da Silva Leite ◽

Amanda Keller Siqueira ◽

...

Keyword(s):

Escherichia Coli ◽

Virulence Factors ◽

Pasteurella Multocida ◽

Anaerobic Bacteria ◽

Sampling Time ◽

Phylogenetic Groups ◽

E Coli ◽

Haemolytic Streptococcus ◽

Early Postpartum ◽

Group Profile

Escherichia coli is the most common contaminant of the bovine uterus in the first few weeks postpartum, and one of the most important pathogens involved in uterine infections. This bacterium is characterised by diverse virulence factors (VF); however, the profile of E. coli VF in physiologic postpartum uterine contamination is not well established. Therefore, the present study aimed to investigate the prevalence of intrauterine bacteria, a set of virulence factors and phylogroups of E. coli isolates, leukogram and uterine cytology in 75 Holstein cows at 24 h (Sampling time 1) and 14 days (Sampling time 2) postpartum. Escherichia coli, α-haemolytic Streptococcus, Trueperella pyogenes, and Pasteurella multocida were the most common microorganisms isolated in pure culture, whereas E. coli and Clostridium perfringens Type A, E. coli and α-haemolytic Streptococcus, and E. coli and Proteus mirabilis were the most frequent microorganisms in mixed colonies at both studied sampling times. In the 59 E. coli isolates after 24 h (n = 35) and 14 days (n = 24) postpartum, the genes detected for VF were fimH, iucD/aer, kps, hlyA, usp, vt1 and vt2. Most E. coli strains detected in both moments of study belonged to Commensal phylogenetic groups A and B1, whereas Pathogenic groups D and B2 were identified at 24 h and 14 days postpartum respectively. All cows presented suitable immune response against the presence of bacteria in uterine lumen, observed by leukocytosis, neutrophilia, lymphocytosis and monocytosis at leukogram and a high number of polymorphonuclear leukocytes in uterine cytology, in both studied moments. Thus, a complex diversity of aerobic and anaerobic bacteria is involved in uterine contamination in the early postpartum of cows, besides the predominance of E. coli. Moreover, the genes fimH, iucD/aer, hlyA, kps, usp, vt1 and vt2 play a key role in the virulence of E. coli in this period.

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Thermal Inactivation of a Single Strain Each of Serotype O26:H11, O45:H2, O103:H2, O104:H4, O111:H−, O121:H19, O145:NM, and O157:H7 Cells of Shiga Toxin–Producing Escherichia coli in Wafers of Ground Beef†

Journal of Food Protection ◽

10.4315/0362-028x.jfp-12-429 ◽

2013 ◽

Vol 76 (8) ◽

pp. 1434-1437 ◽

Cited By ~ 13

Author(s):

J. B. LUCHANSKY ◽

A. C. S. PORTO-FETT ◽

B. A. SHOYER ◽

J. PHILLIPS ◽

D. EBLEN ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Thermal Inactivation ◽

Ground Beef ◽

Sampling Time ◽

Single Strain ◽

E Coli ◽

D Values ◽

Cooking Times ◽

Sterile Filter

For each of two trials, freshly ground beef of variable fat content (higher: 70:30 %lean:%fat; lower: 93:7 %lean:%fat) was separately inoculated with ca. 7.0 log CFU/g of a single strain of Escherichia coli serotypes O26:H11, O45:H2, O103:H2, O104:H4, O111:H−, O121:H19, O145:NM, and O157:H7. Next, ca. 3-g samples of inoculated beef were transferred into sterile filter bags and then flattened (ca. 1.0 mm thick) and vacuum sealed. For each temperature and sampling time, three bags of the inoculated wafers of beef were submerged in a thermostatically controlled water bath and heated to an internal temperature of 54.4°C (130°F) for up to 90 min, to 60°C (140°F) for up to 4 min, or to 65.6°C (150°F) for up to 0.26 min. In lower fat wafers, D-values ranged from 13.5 to 23.6 min, 0.6 to 1.2 min, and 0.05 to 0.08 min at 54.4, 60.0, and 65.6°C, respectively. Heating higher fat wafers to 54.4, 60.0, and 65.6°C generated D-values of 18.7 to 32.6, 0.7 to 1.1, and 0.05 to 0.2 min, respectively. In addition, we observed reductions of ca. 0.7 to 6.7 log CFU/g at 54.4°C after 90 min, ca. 1.1 to 6.1 log CFU/g at 60.0°C after 4 min, and 0.8 to 5.8 log CFU/g at 65.6°C after 0.26 min. Thus, cooking times and temperatures effective for inactivating a serotype O157:H7 strain of E. coli in ground beef were equally effective against the seven non-O157:H7 Shiga toxin–producing strains investigated herein.

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