scholarly journals Statistical Analyses: Possible Reasons for Unreliability of Source Tracking Efforts

2005 ◽  
Vol 71 (8) ◽  
pp. 4690-4695 ◽  
Author(s):  
Clarivel Lasalde ◽  
Roberto Rodríguez ◽  
Gary A. Toranzos
Keyword(s):  
Cluster Analysis ◽  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis ◽  
Microbiological Quality ◽  
Statistical Analyses ◽  
Indicator Organisms ◽  
E Coli ◽  
Quality Of Water

ABSTRACT Analyses for the presence of indicator organisms provide information on the microbiological quality of water. Indicator organisms recommended by the United States Environmental Protection Agency for monitoring the microbiological quality of water include Escherichia coli, a thermotolerant coliform found in the feces of warm-blooded animals. These bacteria can also be isolated from environmental sources such as the recreational and pristine waters of tropical rain forests in the absence of fecal contamination. In the present study, E. coli isolates were compared to E. coli K12 (ATCC 29425) by restriction fragment length polymorphism using pulsed-field gel electrophoresis. Theoretically, genomic DNA patterns generated by PFGE are highly specific for the different isolates of an organism and can be used to identify variability between environmental and fecal isolates. Our results indicate a different band pattern for almost every one of the E. coli isolates analyzed. Cluster analysis did not show any relations between isolates and their source of origin. Only the discriminant function analysis grouped the samples with the source of origin. The discrepancy observed between the cluster analysis and discriminant function analysis relies on their mathematical basis. Our validation analyses indicate the presence of an artifact (i.e., grouping of environmental versus fecal samples as a product of the statistical analyses used and not as a result of separation in terms of source of origin) in the classification results; therefore, the large genetic heterogeneity observed in these E. coli populations makes the grouping of isolates by source rather difficult, if not impossible.

scholarly journals Are the defined substrate-based methods adequate to determine the microbiological quality of natural recreational waters?

2009 ◽  
Vol 8 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Marta Sofia Valente ◽  
Paulo Pedro ◽  
M. Carmen Alonso ◽  
Juan J. Borrego ◽  
Lídia Dionísio
Keyword(s):  
Standard Method ◽  
Membrane Filtration ◽  
Microbiological Quality ◽  
Recreational Waters ◽  
Total Coliforms ◽  
E Coli ◽  
Quality Of Water ◽  
Routine Monitoring ◽  
Rapid Tests

Monitoring the microbiological quality of water used for recreational activities is very important to human public health. Although the sanitary quality of recreational marine waters could be evaluated by standard methods, they are time-consuming and need confirmation. For these reasons, faster and more sensitive methods, such as the defined substrate-based technology, have been developed. In the present work, we have compared the standard method of membrane filtration using Tergitol-TTC agar for total coliforms and Escherichia coli, and Slanetz and Bartley agar for enterococci, and the IDEXX defined substrate technology for these faecal pollution indicators to determine the microbiological quality of natural recreational waters. ISO 17994:2004 standard was used to compare these methods. The IDEXX for total coliforms and E. coli, Colilert®, showed higher values than those obtained by the standard method. Enterolert® test, for the enumeration of enterococci, showed lower values when compared with the standard method. It may be concluded that more studies to evaluate the precision and accuracy of the rapid tests are required in order to apply them for routine monitoring of marine and freshwater recreational bathing areas. The main advantages of these methods are that they are more specific, feasible and simpler than the standard methodology.

Assessment of the Microbiological Quality of Meat Pies from Retail Sale in England 2013

2016 ◽  
Vol 79 (5) ◽  
pp. 781-788 ◽  
Author(s):  
JIM McLAUCHLIN ◽  
HEATHER AIRD ◽  
ANDRE CHARLETT ◽  
NICOLA ELVISS ◽  
ANDREW FOX ◽  
...  
Keyword(s):  
Food Poisoning ◽  
Microbiological Quality ◽  
Foodborne Illness ◽  
Indicator Organisms ◽  
E Coli ◽  
Microbiological Parameters ◽  
Bacillus Spp ◽  
The Individual ◽  
Coagulase Positive Staphylococci

ABSTRACT Outbreaks of foodborne illness caused by Bacillus cereus and Listeria monocytogenes in England associated with meat pie consumption were detected in 2012. To obtain baseline data for pies unrelated to outbreaks, 862 samples of ready-to-eat meat pies were collected at retail or from catering facilities in England in 2013 and examined to enumerate food-poisoning bacteria and indicator organisms using Organization for Standardization (ISO) methods for Listeria spp. including L. monocytogenes (ISO 11290), Clostridium perfringens (ISO 21528), coagulase-positive staphylococci including Staphylococcus aureus (ISO 6888), Bacillus spp. including B. cereus (ISO 1737), Escherichia coli (ISO 16649), Enterobacteriaceae (ISO 21528), and aerobic colony counts (ACCs; ISO 4833). Microbiological quality was satisfactory in 94% of samples, borderline in 5%, and unsatisfactory in 1%. The proportion of pies from markets that were borderline or unsatisfactory significantly increased, and the proportion of borderline or unsatisfactory pies from supermarkets significantly decreased. Among the refrigerated (0 to 15°C) pies, microbiological quality significantly decreased in pies stored at >8°C and further significantly decreased at in pies stored at ambient temperature (>15 to 25°C). Samples collected at 25 to 40°C had the highest proportion of borderline or unsatisfactory results, but results improved in pies stored at >40°C. The most common cause for borderline or unsatisfactory results was elevated ACCs (5% of all samples). Within the individual microbiological parameters, borderline or unsatisfactory results resulted from elevated Enterobacteriaceae or Bacillus levels (10 samples for each), C. perfringens levels (2 samples), and S. aureus or E. coli levels (1 sample each). L. monocytogenes was recovered from one pie at <10 CFU/g. A literature review revealed a range of microbiological hazards responsible for food poisoning and meat pie consumption, and surveillance data from 1992 to 2012 from England indicated that C. perfringens was the most commonly reported cause of outbreaks of foodborne illness.

Male-Specific Coliphages as an Additional Fecal Contamination Indicator for Screening Fresh Carrots

2003 ◽  
Vol 66 (1) ◽  
pp. 88-93 ◽  
Author(s):  
SEEMA ENDLEY ◽  
LINGENG LU ◽  
EVERARDO VEGA ◽  
MICHAEL E. HUME ◽  
SURESH D. PILLAI
Keyword(s):  
Fecal Contamination ◽  
Microbiological Quality ◽  
Indicator Organisms ◽  
Viral Pathogens ◽  
E Coli ◽  
Bacterial Contaminants ◽  
Viral Indicators ◽  
Additional Level ◽  
Male Specific

The objective of this study was to evaluate the efficacy of male-specific (F+) coliphages as a fecal-contaminationindicator for fresh carrots. The prevalence of specific pathogens and indicator organisms on the surface of carrots obtained from a farm, truck, and processing shed was studied. Twenty-five carrot samples collected from each of these locations were washed, and aliquots of the wash were analyzed for the presence of F+ coliphages, Escherichia coli, Salmonella, and Shigella. Additionally, the Salmonella isolates were genotyped using pulsed-field gel electrophoresis (PFGE). Our studies detected the presence of F+ coliphages, E. coli, and Salmonella on carrots. All samples, however, tested negative for Shigella. Although none of the carrot samples from the field were positive for E. coli, one sample was positive for Salmonella, and another was positive for F+ coliphages. From the truck, two carrot samples (8%) were positive for Salmonella, four (16%) were positive for F+ coliphages, and four (16%) were positive for E. coli. None of the carrot samples from the processing shed were positive for Salmonella. However, 2 carrot samples (8%) were positive for E. coli, and 14 carrot samples (56%) were positive for F+ coliphages. The PFGE results suggest that there were three distinct Salmonella genotypes among the carrot samples from the truck and that the Salmonella isolates identified on carrot samples from the field and truck locations were different. Microbiological screening of fresh produce such as carrots (which can be exposed to fecal contaminants in soils and water) should ensure the detection of both viral and bacterial contaminants. Overall, in this study, F+ coliphages were detected in 25% of the carrot samples, compared to E. coli (8%), Salmonella (4%), and Shigella (0%). The results suggest F+ coliphages can serve as a conservative indicator of fecally associated viruses on carrots. This suggests that in addition to E. coli screening, F+ coliphages should be included when produce such as carrots that are vulnerable to fecal contaminants are screened. Since the detection of specific enteric viral pathogens is expensive, screening for viral indicators of fecal contamination using F+ coliphages can be an economical approach to providing an additional level of assurance about the microbiological quality of fresh carrots.

A Technique for Identifying the Subgroup Membership of Certain Misarticulating Children

1982 ◽  
Vol 25 (2) ◽  
pp. 162-166 ◽  
Author(s):  
Anita F. Johnson ◽  
Ralph L. Shelton ◽  
William B. Arndt
Keyword(s):  
Cluster Analysis ◽  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Auditory Processing ◽  
Function Analysis ◽  
Cluster Membership ◽  
Reading Measures

Cluster analysis was used to identify two homogenous clusters of 8–9½-year-old children who misarticulated /s/, /r/, or both. The analysis was based on the children's scores on 40 measures of language, reading, auditory processing, and other variables. Discriminant function analysis was then used to identify a subset of five measures and a means of computing classification scores. These measures and the classification scores can be used to identify the cluster membership of new subjects. The use of classification scores for identifying cluster membership was cross-validated against cluster analysis of a second group of children. The two clusters are described in terms of their performance on language and reading measures.

scholarly journals The effect of container-biofilm on the microbiological quality of water used from plastic household containers

2003 ◽  
Vol 1 (3) ◽  
pp. 101-108 ◽  
Author(s):  
P. Jagals ◽  
C. Jagals ◽  
T. C. Bokako
Keyword(s):  
Heterotrophic Bacteria ◽  
Microbiological Quality ◽  
Total Coliform ◽  
Human Consumption ◽  
Microbiological Contamination ◽  
Supply Source ◽  
E Coli ◽  
Quality Of Water ◽  
Storage Containers

Studies in Southern Africa have shown that even when microbiologically safe water is supplied to developing communities at communal standpipes, contamination by high numbers of pathogenic microorganisms may occur during the processes of fetching water from the supply source and storage during use at home, rendering such waters unsafe for human consumption. This study investigated the occurrence of biofilm in PVC storage containers as one possible reason for this deterioration, using heterotrophic bacteria and total coliform counts as well as turbidity as indicators. A second objective was to determine whether biofilm in water-storage containers could contribute to hazardous microbiological contamination indicated by Escherichia coli and Clostridium perfringens. Results indicated that increased microbiological contamination is associated with biofilm. The biofilm harbours heterotrophic bacteria, total coliforms and C. perfringens. E. coli could not be associated directly with the levels of biofilm in containers but rather appears to be introduced intermittently from the ambient domestic environment. When dislodged with the biofilm, these bacteria contributed substantially to the deterioration of the microbiological quality of supplied water stored in plastic containers.

Academic Goal Profiles: A Comparison of Blind and Sighted Students

2012 ◽  
Vol 15 (3) ◽  
pp. 1043-1054 ◽  
Author(s):  
Francisco Pablo Holgado Tello ◽  
Leandro Navas Martínez ◽  
Irene Jover Mira
Keyword(s):  
Cluster Analysis ◽  
Factor Analysis ◽  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Visually Impaired ◽  
Function Analysis ◽  
Goal Theory ◽  
Academic Goals ◽  
Visually Impaired Students

Based on academic goal theory, we compared the goals of visually impaired and sighted students. Participants included 171 students affiliated with ONCE (the National Spanish Organization for the Blind) and 163 sighted students, ranging from 8 to 27 years of age, who responded to the Spanish adaptation (González, Torregrosa, & Navas, 2002) of the goals questionnaire created by Hayamizu, Ito, and Yohiazaki (1989) and Hayamizu and Weiner (1991). Factor analysis indicated that goals varied among these students and that new ones arose in this study; furthermore, the model remained invariable regardless of students' status (visually impaired versus sighted). Cluster analysis revealed three distinct profiles in terms of academic goals, while discriminant function analysis suggested these profiles vary as a function of students' status (visually impaired versus sighted). It seems that visually impaired students hold more learning-oriented academic goals.

Microbiological Quality of Water Immersion–Chilled and Air-Chilled Broilers

2011 ◽  
Vol 74 (9) ◽  
pp. 1531-1535 ◽  
Author(s):  
LEI ZHANG ◽  
JONG Y. JEONG ◽  
KISHOREKUMAR K. JANARDHANAN ◽  
ELLIOT T. RYSER ◽  
IKSOON KANG
Keyword(s):  
Water Immersion ◽  
Cetylpyridinium Chloride ◽  
Microbiological Quality ◽  
E Coli ◽  
Quality Of Water ◽  
Spoilage Bacteria ◽  
Processing Line ◽  
Commercial Processing ◽  
On Farm

Carcass chilling during broiler processing is a critical step in preventing growth of pathogenic and spoilage bacteria. The objective of this study was to compare the microbiological quality of air- and water-chilled broiler carcasses processed at the same commercial facility. For each of four replications, 15 broilers were collected from the same commercial processing line after evisceration, after spraying with cetylpyridinium chloride (a cationic disinfectant), and after air chilling or water immersion chilling (WIC). All carcasses were quantitatively examined for mesophilic aerobic bacteria, Escherichia coli, coliforms, and Campylobacter as well as for the presence of Salmonella and Campylobacter. No significant differences (P > 0.05) were seen between air and water chilling for E. coli or coliforms or for the incidence of Salmonella and Campylobacter. Lower numbers of Campylobacter were recovered from WIC than from air-chilled carcasses (P < 0.05), but the incidence of Campylobacter on WIC carcasses was similar, suggesting that some Campylobacter organisms were injured rather than killed during WIC. In-line spraying with the disinfectant effectively decreased the incidence of Salmonella and Campylobacter on prechilled carcasses; however, cells presumably injured by the sanitizer recovered during chilling. Therefore, on-farm intervention strategies remain critically important in minimizing the spread of microbial contaminants during processing.

scholarly journals Management of Microbiological Contamination of the Water Network of a Newly Built Hospital Pavilion

Pathogens ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 75
Author(s):  
Osvalda De Giglio ◽  
Giusy Diella ◽  
Marco Lopuzzo ◽  
Francesco Triggiano ◽  
Carla Calia ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Microbiological Quality ◽  
Silver Ions ◽  
Waterborne Diseases ◽  
Water Safety ◽  
Water Network ◽  
E Coli ◽  
Quality Of Water ◽  
Water Safety Plan

The good installation, as well as commissioning plan, of a water network is a crucial step in reducing the risk of waterborne diseases. The aim of this study was to monitor the microbiological quality of water from a newly built pavilion before it commenced operation. Overall, 91 water samples were tested for coliforms, Escherichia coli, enterococci, Pseudomonas aeruginosa and Legionella at three different times: T0 (without any water treatment), T1 (after treatment with hydrogen peroxide and silver ions at initial concentration of 20 mg/L and after flushing of water for 20 min/day for seven successive days) and T2 (15 days later). Coliforms were detected in 47.3% of samples at T0, 36.3% at T1 and 4.4% at T2. E. coli was isolated in 4.4% of the samples only at T1, while enterococci appeared in 12.1% of the samples at T1 and in 2.2% at T2. P. aeruginosa was isolated in 50.5% of the samples at T0, 29.7% at T1 and 1.1% at T2. Legionella pneumophila serogroup 8 was isolated in 80.2% of the samples at T0, 36.3% at T1 and 2.2% at T2. Our results confirmed the need for a water safety plan in new hospital pavilions to prevent the risk of waterborne diseases.

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