Effect of Stress and Resuscitation on Recovery of Indicator Bacteria from Foods Using Hydrophobic Grid-Membrane Filtration

1982 ◽  
Vol 45 (14) ◽  
pp. 1326-1331 ◽  
Author(s):  
M. H. BRODSKY ◽  
P. BOLESZCZUK ◽  
P. ENTIS
Keyword(s):  
Membrane Filtration ◽  
Membrane Filter ◽  
Indicator Bacteria ◽  
Poultry Meat ◽  
Most Probable Number ◽  
Indicator Organism ◽  
Plate Method ◽  
Probable Number ◽  
E Coli ◽  
Raw Poultry

The effects of stress and resuscitation on selective enumeration of coliforms, Escherichia coli and enterococci in mechanically deboned raw poultry meat and in dried foods were studied using a hydrophobic grid membrane filter (HGMF) technique. The effects of four different stresses, sublethal heating, freezing, acid pH and drying, were examined on 25 to 30 samples per indicator organism for each type of stress. Counts obtained with resuscitation were compared statistically to direct selective counts for each series of samples. Also, both the direct and resuscitative HGMF results were compared to a 5-tube most probable number method for coliforms and E. coli and to a spread plate method for the enterococci. The use of appropriate resuscitation procedures not only produced a significant increase in counts over the direct HGMF procedure, but also yielded HGMF results that were statistically equivalent to those obtained by conventional methods.

Enumeration of Indicator Organisms in Foods Using the Automated Hydrophobic Grid-Membrane Filter Technique

1982 ◽  
Vol 45 (4) ◽  
pp. 292-296 ◽  
Author(s):  
M. H. BRODSKY ◽  
P. ENTIS ◽  
A. N. SHARPE ◽  
G. A. JARVIS
Keyword(s):  
Membrane Filtration ◽  
Membrane Filter ◽  
Optimal Recovery ◽  
Most Probable Number ◽  
Indicator Organisms ◽  
Probable Number ◽  
E Coli ◽  
Stressed Cells ◽  
And Staphylococcus Aureus ◽  
Filtration Technique

The automated HGMF technique was compared against accepted traditional methodology for the recovery and enumeration of coliforms, Escherichia coli, enterococci and Staphylococcus aureus from a variety of naturally and artificially contaminated foods. The overall ratios of recovery of the HGMF relative to conventional methods were 0.88 for coliforms, 0.80 for E. coli, 0.81 for enterococci and 0.80 for S. aureus. Our results suggest that the automated HGMF system is a viable alternative to conventional most-probable-number and spread plate techniques for the isolation and enumeration of foodborne microorganisms on selective media; however, consideration must be given to modifying procedures for the optimal recovery of stressed cells by this automated membrane filtration technique.

The relationship between three potential pathogens and pollution indicator organisms in Nova Scotian coastal waters

1983 ◽  
Vol 29 (10) ◽  
pp. 1261-1269 ◽  
Author(s):  
W. J. Robertson ◽  
R. S. Tobin
Keyword(s):  
Membrane Filtration ◽  
Indicator Bacteria ◽  
Fecal Coliforms ◽  
Most Probable Number ◽  
Indicator Organisms ◽  
Fecal Indicator ◽  
Filtration Method ◽  
Probable Number ◽  
Pollution Indicator ◽  
Nova Scotian

Fifteen stations, in two estuaries, along the Northumberland Strait of Nova Scotia were examined between June and September 1981 for a relationship between the concentrations of commonly monitored fecal indicator bacteria and the potential pathogens Candida albicans, Pseudomonas aeruginosa, and Vibrio parahaemolyticus. Increased densities of these three organisms were usually associated with high densities of indicator bacteria. Whereas C. albicans and P. aeruginosa occur in human fecal wastes, V. parahaemolyticus is indigenous to the marine environment and positively responds to elevated nutrient levels in sewage. There is also some evidence that these bacteria survive as long or longer in marine waters than the common indicator bacteria. While membrane-filtration techniques for the enumeration of C. albicans and P. aeruginosa proved satisfactory, a V. parahaemolyticus membrane-filtration method lacked specificity and was supplemented by a most-probable-number method. In marine recreational and shellfish waters, these three organisms could complement fecal coliforms and fecal streptococci as indicators of human fecal contamination.

scholarly journals Rapid single-tube confirmatory test forEscherichia coli

1982 ◽  
Vol 89 (1) ◽  
pp. 149-154 ◽  
Author(s):  
J. L. Smith ◽  
S. Rockliff
Keyword(s):  
Membrane Filtration ◽  
Confirmatory Test ◽  
Most Probable Number ◽  
Standing Committee ◽  
Traditional Methods ◽  
Probable Number ◽  
Single Tube ◽  
Laboratory Service ◽  
The Public ◽  
E Coli

SUMMARYA single-tube confirmatory test that allows a result to be obtained in 4 h has been developed from the single-tube confirmatory test recommended by the Joint Committee of the Public Health Laboratory Service and the Standing Committee of Analysts (PHLS/SCA, 1980). A variety of river, lake and reservoir samples were examined for the presence ofE. coliusing either most probable number (MPN) or membrane filtration (MF) technique, and the PHLS/SCA recommended confirmatory medium (LTMB) was evaluated against traditional methods. To improve the performance of LTMB, the medium was modified and this modified medium when used in 0·1 ml volumes and incubated for 4 h at 44°C provided 99% agreement with traditional methods.

Monitoring of E. coli and Enterococci in Lake Michigan Beach Sand

2020 ◽  
Author(s):  
Jin Li ◽  
Brett Bevers ◽  
Nabila Nafsin ◽  
Qian Liao
Keyword(s):  
Water Quality ◽  
Lake Michigan ◽  
Indicator Bacteria ◽  
Beach Sand ◽  
Most Probable Number ◽  
Probable Number ◽  
E Coli ◽  
Sampling Duration ◽  
The Impact ◽  
Mean Concentration

<p>Excessive fecal indicator bacteria concentration leads to swimming advisories that are very common to freshwater beaches. To evaluate the concentration and interaction of indicator bacteria in beach sand and water and to examine the factors that affect bacteria concentration, a study was undertaken at Bradford beach, Milwaukee county on the shore of Lake Michigan. In this research, results from monitoring of E. coli and Enterococci in sand and water from Lake Michigan beach were presented. Bacteria counts were obtained using the IDEXX Most Probable Number (MPN) method. An attempt was made to establish a direct ratio of bacteria counts between the two most common eluents used to detach bacteria from sand, i.e., deionized water (DI) and phosphate buffered saline (PBS). The beach sand bacteria count was analyzed using the EPA CANARY event detection software to identify the onset of periods of anomalous water quality. Analysis of beach sand from this study show that for E. coli, it may be possible to establish a relationship between the results generated using two eluents. Results from the model indicates that sand can be a better potential reservoir for indicator bacteria survival than water as a source. The results also show that CANARY may be useful as an early warning system for monitoring beach contamination and may help to identify any abnormal condition very quickly. Also, in this study, the factors that contributed to the high concentration of bacteria resulting in abnormal water quality events are examined which are the impact of Algae in beach water sample and the rainfall effect during the overall month of sampling duration. CANARY software can best indicate the impact of the presence of Algae on bacteria concentration. The analysis of rainfall effect on bacteria concentration was done using statistical software by determining the significance (p-value) between the seasonal mean concentration of E. coli and the mean concentration of E. coli during the sampling duration and from the analyses it is evaluated that rainfall does affect the bacteria concentration. Moreover, the correlation coefficient indicates greater impact of rainfall event on bacteria concentration relative to the presence of Algae level. Regression analysis was also done to estimate the best model that describes the relation between E. coli and water temperature resulting in weak negative linear relationship between the variables.</p>

scholarly journals Two Rapid Methods for Detection of Escherichia coli Exceeding 104/g Action Levels: Precollaborative Study

2006 ◽  
Vol 89 (5) ◽  
pp. 1317-1326
Author(s):  
Michael A Grant ◽  
Jane S Wernberg ◽  
Khanh T Van ◽  
Angelina M Albert
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Reference Method ◽  
Most Probable Number ◽  
Lauryl Sulfate ◽  
Probable Number ◽  
E Coli ◽  
Potential Alternative ◽  
Aoac Method ◽  
Action Levels

Abstract The current AOAC Method 966.24 for enumeration of Escherichia coli in foods uses a most probable number (MPN) procedure with extensive confirmation steps. Two new methods based on membrane filtration (MF) were compared to the MPN reference method for detection of high levels of E. coli in 5 food types, some of which represent categories for which the U.S. Food and Drug Administration (FDA) mandates additional testing if an action level of 104/g E. coli is exceeded. Ground beef, which is not FDA regulated, was also tested. The 5 food types were all inoculated at 3 levels: 102/g, ≥104/g, and ≥105/g E. coli. An MF protocol using either m-ColiBlue24® (CB) or lauryl sulfate tryptose plus BCIG (LST/BCIG) was an effective potential alternative to the reference method. Sensitivity and specificity for both CB and LST/BCIG were 98 and 100%, respectively. Agreement between MPN and both CB and LST/BCIG was 98%. The 2 proposed methods allow completion of both presumptive and confirmatory steps in 13 days, whereas the reference method requires as many as 11 days. Exclusivity testing with 50 non-E. coli strains indicated 100% were correctly ruled out by the proposed protocols. Inclusivity testing was used to determine whether typical results were obtained after incubation of E. coli cultures on CB or LST/BCIG for 24 h. Of 50 E. coli strains tested, 100% yielded typical results after incubation on CB, and 98% yielded typical results after incubation on LST/BCIG.

Membrane Filter Method Based on FC-5-Bromo-4-Chloro-3-lndolyl-β-d-Glucuronide Medium Facilitates Enumeration of Escherichia coli in Foods and Poultry Carcass Rinses

1998 ◽  
Vol 61 (3) ◽  
pp. 360-364 ◽  
Author(s):  
A. N. SHARPE ◽  
L. J. PARRINGTON
Keyword(s):  
Escherichia Coli ◽  
Membrane Filter ◽  
Most Probable Number ◽  
Filter Method ◽  
Simple Method ◽  
Probable Number ◽  
E Coli ◽  
Membrane Filter Method ◽  
Alfalfa Sprouts ◽  
Bean Sprouts

Three enumeration methods for Escherichia coli in foods, the Health Protection Branch most-probable-number (MPN) method MFHPB-19, a hydrophobic grid membrane filter method MFHPB-26 (HGMF-indole), and a hydrophobic grid membrane filter method utilizing 5-bromo-4-chloro-3-indolyl-β-d-glucuronide in a (modified) mFC agar (HGMF-FC-BCIG) were compared in 80 food samples that included naturally and artificially contaminated raw vegetables, mung bean and alfalfa sprouts, raw meats, and chicken carcass rinses. The number of samples confirmed as positive for E. coli were 44, 36, and 42 for the MPN, HGMF-indole, and HGMF-FC-BCIG methods, respectively. By the MPN method, E. coli was detected in 3 samples at levels below the limits of detection of the HGMFs; but the MPN method was very time-consuming. With the HGMF-indole procedure E. coli was missed in 4 artificially contaminated samples. With the HGMF-FC-BCIG method E. coli was enumerated in 1 sample of bean sprouts missed by both the MPN and HGMF-indole procedures. High levels of indole-positive Klebsiella spp. in bean sprouts interfered with the HGMF-indole method, but the blue colonies of E. coli were easily observed in the HGMF-FC-BCIG method. Specificity of the HGMF-FC-BCIG method is high enough that routine confirmation should be unnecessary; however, confirmation of presumptive E. coli is easier since no lethal indole-staining step is involved. It appears to be a very simple method for quantifying E. coli in foods or carcass rinses.

Development and evaluation of methods to detect coliphages in large volumes of water

2004 ◽  
Vol 50 (1) ◽  
pp. 211-217 ◽  
Author(s):  
M.D. Sobsey ◽  
M.V. Yates ◽  
F-C. Hsu ◽  
G. Lovelace ◽  
D. Battigelli ◽  
...  
Keyword(s):  
Membrane Filter ◽  
Most Probable Number ◽  
Filter Method ◽  
Cellulose Ester ◽  
Enrichment Method ◽  
Probable Number ◽  
E Coli ◽  
Filter Methods ◽  
Water Volumes ◽  
Male Specific

New and improved methods have been developed to detect somatic and male-specific coliphages in large volumes of water by single agar layer (SAL), enrichment and membrane filter methods. Somatic coliphages were detected efficiently on E. coli hosts C and CN13, male-specific coliphages were detected more efficiently on E. coli Famp than on Salmonella typhimurium WG49 and both types of coliphages were detected simultaneously on E. coli C3000. For water volumes of up to 100 ml, the SAL method was efficient and reliable. For water volumes of <1 L and as many as 10 multiple 1 L volumes, the enrichment method was efficient in detecting very low numbers of coliphages. Membrane filter methods, in which coliphages were adsorbed to and eluted from filters, also were relatively efficient, but they were less efficient than SAL and enrichment methods and were considered to be more cumbersome. For filter adsorption-elution methods, coliphage recoveries were most efficient for cellulose ester filters, less efficient for electropositive 1MDS filters and least efficient for a direct membrane filter method. Overall, the enrichment method was preferred because of its ability to easily and rapidly detect low levels of coliphages in large sample volumes by either presence-absence or most probable number quantification.

Aerobic Plate Counts of 100-ml Samples in Plastic Bags1

1987 ◽  
Vol 50 (4) ◽  
pp. 296-299
Author(s):  
SOPHIA G. CAMPBELL ◽  
PAUL A. HARTMAN
Keyword(s):  
Membrane Filtration ◽  
Most Probable Number ◽  
Plate Method ◽  
Probable Number ◽  
Direct Plating ◽  
Viable Bacteria ◽  
Plate Counts ◽  
Agar Media

Counts from samples that contained low numbers of bacteria were determined by mixing the samples with double-strength agar media in 42-oz (1.2-L) Whirl-Pak bags. The bag-plate method was compared with other direct-plating methods and the most-probable-number and membrane-filtration procedures. Results obtained by using the bag method were as reliable as methods commonly used for analysis of samples that contain low numbers of viable bacteria.

Quantification, Serovars, and Antibiotic Resistance of Salmonella Isolated from Retail Raw Chicken Meat in Vietnam

2014 ◽  
Vol 77 (1) ◽  
pp. 57-66 ◽  
Author(s):  
YEN T. TA ◽  
TRUNG THANH NGUYEN ◽  
PHUONG BICH TO ◽  
DA XUAN PHAM ◽  
HAO THI HONG LE ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Production System ◽  
Chicken Meat ◽  
Poultry Meat ◽  
Most Probable Number ◽  
Probable Number ◽  
Phenotypic Resistance ◽  
Cell Counts ◽  
Significant Difference ◽  
Raw Poultry

The objectives of this study were to quantify Salmonella counts on retail raw poultry meat in Vietnam and to phenotypically characterize (serovars and antibiotic resistance) the isolates. A total of 300 chicken carcasses were collected from two cities and two provinces in Vietnam. Salmonella counts on the samples were determined according to the most-probable-number (MPN) method of the U.S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS). A total of 457 isolates were serotyped and tested for antibiotic susceptibility. Overall, 48.7% of chicken samples were Salmonella positive with a count of 2.0 log MPN per carcass. There were no significant differences (P > 0.05) in log MPN per carcass by the study variables (market type, storage condition, and chicken production system). There was a significant difference (P < 0.05) in Salmonella-positive prevalence by chicken production system. Among the 22 Salmonella serovars identified, Albany was the most frequent (34.1%), followed by Agona (15.5%) and Dabou (8.8%). Resistance to at least one antibiotic was common (i.e., 73.3%), with high resistance to tetracycline (59.1%) and ampicillin (41.6%). Resistance to three antibiotics was the most frequently found multidrug resistance profile (17.7%, n = 81); the profile that was resistant to the highest number of drugs was resistant to nine antibiotics (0.7%, n = 3). Only Salmonella Albany posed phenotypic resistance to ceftriaxone (a drug of choice to treat severe cases of salmonellosis). The data revealed that, whereas Salmonella prevalence on raw poultry was high (48.7%), counts were low, which suggests that the exposure risk to Salmonella is low. However, improper storage of raw chicken meat and cross-contamination may increase Salmonella cell counts and pose a greater risk for infection. These data may be helpful in developing risk assessment models and preventing the transmission of foodborne Salmonella from poultry to humans in Vietnam.

Detection of Escherichia coli in Drinking Water Sources of Filter Units and Supply Water

2016 ◽  
Vol 19 (2) ◽  
pp. 206-210
Author(s):  
Arman Chowdhory ◽  
Nafisa Kabir ◽  
Md Mazharul Islam Chowdhury ◽  
Jakir Ahmed Chowdhury
Keyword(s):  
Drinking Water ◽  
Membrane Filtration ◽  
Tap Water ◽  
Pharmaceutical Journal ◽  
Water Sources ◽  
Most Probable Number ◽  
Probable Number ◽  
E Coli ◽  
Bacteriological Test ◽  
Positive Results

The identification of coliforms has been extensively used as an indicator of drinking water quality. The study was aimed to identify the presence or absence of E. coli from drinking water. Samples were collected from different filtration units and tap water sources of an institution in Dhaka city. All the samples were tested through presumptive, confirmed and completed bacteriological test through MPN (most probable number) using 3 sets of lactose broth (LB) media and MF (membrane filtration) technique using bacteriological filter and nutrient agar media to find out the CFU (colony forming unit). About 10% of samples showed positive results for E. coli in completed test, and also gave positive results in confirmed test and gram staining; having no more than 1100 MPN per 100 ml for samples of filter taps but the source water remained negative.Bangladesh Pharmaceutical Journal 19(2): 206-210, 2016

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