Comparative quantification of Campylobacter jejuni from environmental samples using traditional and molecular biological techniques

2009 ◽  
Vol 55 (6) ◽  
pp. 633-641 ◽  
Author(s):  
Michael J. Rothrock ◽  
Kimberly L. Cook ◽  
Carl H. Bolster
Keyword(s):  
Campylobacter Jejuni ◽  
Environmental Samples ◽  
Limit Of Detection ◽  
Plate Count ◽  
E Coli ◽  
Common Causes ◽  
Plate Counts ◽  
Selective Plate ◽  
Potential Risks ◽  
Cell Concentrations

Campylobacter jejuni is one of the most common causes of gastroenteritis in the world. Given the potential risks to human, animal, and environmental health, the development and optimization of methods to quantify this important pathogen in environmental samples is essential. Two of the most commonly used methods for quantifying C. jejuni are selective plate counting and quantitative real-time PCR (qPCR). Unfortunately, little comparative research has been performed to evaluate the accuracy of these methods for quantification of C. jejuni in aqueous and solid matricies. In this study, the limit of detection and the level of resolution obtained using these 2 methods was evaluated for C. jejuni and compared with that of the common indicator organism Escherichia coli . The use of selective plate count media for quantification of C. jejuni resulted in a 0.7–1.2 log underestimation of cell concentrations, compared with qPCR in both water and column leachate samples, whereas E. coli concentrations were found to be similar with either technique. For C. jejuni, only the qPCR assay accurately measured 2-fold changes in cell concentrations in water samples, whereas concentrations of E. coli were accurately measured regardless of method. Based on these data, qPCR assays were found to be more accurate than selective plate counts for quantification of C. jejuni from environmental samples.

Microbiological investigations of rainwater and graywater collected for toilet flushing

2002 ◽  
Vol 46 (6-7) ◽  
pp. 311-316 ◽  
Author(s):  
H.-J. Albrechtsen
Keyword(s):  
Campylobacter Jejuni ◽  
Microbiological Quality ◽  
Plate Count ◽  
Microbial Water Quality ◽  
E Coli ◽  
Plate Count Agar ◽  
Hand Wash ◽  
Plate Counts ◽  
Heterotrophic Plate Counts ◽  
Micro Organisms

Seven Danish rainwater systems were investigated with respect to the microbial water quality. The general microbiological quality (total numbers of bacteria (AODC)), and heterotrophic plate counts on R2A and Plate Count Agar in the toilets supplied with rainwater were approximately the same as in the reference toilets supplied with drinking water. However, in 12 of the 27 analysed samples one or more pathogens were observed (Aeromonas sp., Pseudomonas aeruginosa, Legionella non-pneumophila, Campylobacter jejuni, Mycobacterium avium, and Cryptosporidium sp.). These pathogens were not found in any of the reference toilets (32 toilets). This means that the use of rainwater introduced new, potentially pathogenic micro-organisms into the households which would normally not occur in toilets supplied with water from waterworks. Furthermore, four graywater systems were investigated where water from the shower and hand wash basin was reused. The graywater systems gave more problems in terms of bad smell and substantially higher numbers of E. coli and Enterococcus in some toilet bowls supplied with graywater.

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

2016 ◽  
Vol 79 (7) ◽  
pp. 1143-1153 ◽  
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.

Low Prevalence of Salmonella and Shiga Toxin–Producing Escherichia coli in Lymph Nodes of Australian Beef Cattle

2017 ◽  
Vol 80 (12) ◽  
pp. 2105-2111 ◽  
Author(s):  
Gavin Bailey ◽  
Long Huynh ◽  
Lachlan Govenlock ◽  
David Jordan ◽  
Ian Jenson
Keyword(s):  
Escherichia Coli ◽  
Lymph Nodes ◽  
Shiga Toxin ◽  
Limit Of Detection ◽  
Ground Beef ◽  
Plate Count ◽  
Salmonella Spp ◽  
Live Animal ◽  
E Coli ◽  
Low Prevalence

ABSTRACT Salmonella contamination of ground beef has been viewed as originating from the surface of carcasses. Recent studies have identified lymph nodes as a potential source of Salmonella contamination because these tissues play an active role in containment of pathogens in the live animal and because some lymph nodes are unavoidably present in manufacturing beef trimmings or primal cuts that may be incorporated into ground beef. A survey was conducted of the microbiological status of lymph nodes from Australian cattle at the time of slaughter to determine the prevalence of microbiological contamination. Sets of lymph nodes (n = 197), consisting of the superficial cervical (prescapular), prepectoral, axillary, presternal, popliteal, ischiatic, subiliac (precrural), coxalis, and iliofemoralis (deep inguinal), were collected from five geographically separated Australian abattoirs over a period of 14 months. Samples were tested for the presence of Salmonella spp. and Shiga toxin–producing Escherichia coli by BAX PCR assay. Aerobic plate count, E. coli, and coliforms were enumerated with a lower limit of detection of 80 CFU per node. The observed prevalence of Salmonella within peripheral lymph nodes was 0.48% (7 of 1,464). Two of the seven lymph nodes in which Salmonella organisms were detected came from the same animal. Grass-fed, grain-fed, and cull dairy cattle were all found to have detectable Salmonella in lymph nodes. All Salmonella detections occurred during cooler months of the year. No Shiga toxin–producing E. coli were detected. Aerobic microorganisms were detected above the limit of quantification in 3.2% of nodes (median count 2.24 log per node), and E. coli was detected in 0.8% of nodes (median count 3.05 log per node). The low prevalence of Salmonella and low concentration of aerobic microorganisms in Salmonella-positive lymph nodes of Australian cattle at the time of slaughter suggest that the likelihood of lymph nodes contributing significantly to the presence of Salmonella in ground beef is low.

Bacterial Contamination in Saeng-go-gi, a Ready-to-Eat Fresh Raw Beef Dish Sold in Restaurants in South Korea

2015 ◽  
Vol 78 (3) ◽  
pp. 619-623 ◽  
Author(s):  
MYOUNG SU PARK ◽  
JIN SAN MOON ◽  
EWEN C. D. TODD ◽  
GYUNG JIN BAHK
Keyword(s):  
Bacterial Contamination ◽  
Latex Agglutination ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Foodborne Illnesses ◽  
E Coli ◽  
Plate Counts ◽  
Handling Practices ◽  
Contamination Levels ◽  
Food Handling Practices

This study investigated the bacterial contamination levels in ready-to-eat fresh raw beef, Saeng-go-gi in Korean, sold in restaurants. A total of 462 samples were analyzed by performing an aerobic bacterial plate count, a coliform count, and an Escherichia coli O157:H7 count. Aerobic bacterial plate counts of fresh raw beef obtained from Seoul, Cheonan, Daegu, Gunsan, and Gwangju retail store restaurants were 6.46, 6.89, 6.39, 6.58, and 6.67 log CFU/g, respectively, and coliforms were 4.05, 4.97, 4.76, 3.62, and 3.32 log CFU/g, respectively. Among the 462 assessed samples, suspected E. coli O157:H7 colonies were found in 32, 24, 20, 22, and 16 samples obtained from Seoul, Cheonan, Daegu, Gunsan, and Gwangju, respectively. The identity of these isolated colonies was further assessed by using a latex agglutination kit. The agglutination assay data showed that the isolates were not E. coli O157:H7. The data from this study could be used to design better food handling practices for reducing foodborne illnesses linked to fresh raw beef consumption.

Comparison of Brands of Media for Isolating Bacteria from Poultry, Beef and Shrimp

1984 ◽  
Vol 47 (5) ◽  
pp. 394-397 ◽  
Author(s):  
H. S. LILLARD ◽  
N. A. COX ◽  
J. S. BAILEY ◽  
J. E. THOMSON
Keyword(s):  
Escherichia Coli ◽  
Practical Significance ◽  
Plate Count ◽  
E Coli ◽  
Plate Counts ◽  
Aerobic Plate Count ◽  
Raw Shrimp

Five brands of media (BBL, Difco, Gibco, Oxoid and Scott) were evaluated for enumerating microorganisms by the aerobic plate count and by Enterobacteriaceae, Escherichia coli, and coliform counts, and for determining Salmonella incidence. Microbiological evaluations were done on raw chickens, raw beef and raw shrimp, except that Salmonella incidence was not determined on shrimp samples. There were statistically significant differences in total plate counts (with chicken, beef and shrimp), Enterobacteriaceae counts (with shrimp) coliforms (with chicken) and E. coli counts (with chicken) by the five brands of media, but these differences were too small to be of practical significance. It was concluded that no differences of practical significance were found among the five brands of media.

Bacteriological Profile of Raw, Frozen Chicken Nuggets

2008 ◽  
Vol 71 (3) ◽  
pp. 613-615 ◽  
Author(s):  
SOFRONI EGLEZOS ◽  
GARY A. DYKES ◽  
BIXING HUANG ◽  
NARELLE FEGAN ◽  
ED STUTTARD
Keyword(s):  
Plate Count ◽  
Chicken Nuggets ◽  
E Coli ◽  
Bacteriological Profile ◽  
Processing Facility ◽  
Plate Counts ◽  
The Mean ◽  
Aerobic Plate Count ◽  
Number Of Bacteria

The bacteriological profile of raw, frozen chicken nuggets manufactured at a chicken processing facility in Queensland, Australia, was determined. Chicken nuggets are manufactured by grinding poultry, adding premixes to incorporate spices, forming the meat to the desired size and shape, applying a batter and breading, freezing, and packaging. A total of 300 frozen batches were analyzed for aerobic plate count, Escherichia coli, and Salmonella over a period of 4 years. The mean of the aerobic plate count was 5.4 log CFU/g, and counts at the 90th, 95th, and 99th percentiles were 5.7, 5.9, and 6.5 log CFU/g, respectively. The maximum number of bacteria detected was 6.6 log CFU/g. E. coli prevalence was 47%, and of the positive samples, the mean was 1.9 log CFU/g; counts at the 90th, 95th, and 99th percentiles were 2.3, 2.4, and 2.8 log CFU/g, respectively. The maximum number of E. coli was 2.9 log CFU/g. The Salmonella prevalence was 8.7%, and 57.7% of these isolates were typed as Salmonella subspecies II 4,12,[27]:b:[e,n,x] (Sofia), a low-virulence serotype well adapted to Australian poultry flocks. There was a significant relationship (P < 0.05) between season and both aerobic plate counts and E. coli counts, and no correlation between E. coli counts and Salmonella prevalence. This study provides valuable data on the bacteriological quality of raw, frozen chicken nuggets.

Destruction de Microbacterium lacticum, Escherichia coli et Staphylococcus aureus au cours du séchage du lait par atomisation. I. Dénombrement sélectif des bactéries survivantes

1977 ◽  
Vol 23 (6) ◽  
pp. 716-720
Author(s):  
A. Chopin ◽  
G. Mocquot ◽  
Y. Le Graet
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Spray Drying ◽  
Skim Milk ◽  
Resistant Mutant ◽  
Plate Count ◽  
Mannitol Salt Agar ◽  
E Coli ◽  
Plate Count Agar ◽  
Plate Counts

In this paper a method which allows the measure of microbial death rate during spray-drying by means of a streptomycin-resistant mutant that can be grown on a streptomycin-containing agar is described. Plate counts of Microbacterium lacticum, Escherichia coli, and Staphylococcus aureus recovered from skim milk powders were done on plate count agar in the presence and absence of streptomycin and on various selective media. The powders were produced from evaporated milk previously inoculated with those organisms.Our results showed that the proposed method allows the recovery of 78% of M. lacticum, 61% of E. coli, and 100% of S. aureus that survived spray-drying. Recoveries of surviving E. coli on violet bile agar and brilliant green bile 2% were 34% and 29% respectively. Baird-Parker and mannitol salt agar media allow the recovery of all surviving S. aureus, thus showing that S. aureus cells did not lose their ability to grow in media containing 7.5% NaCl. Our results show that physiological injury of the cells during spray-drying differs from injury due to heating only. [Traduit par le journal]

Use of Simulation Tools To Illustrate the Effect of Data Management Practices for Low and Negative Plate Counts on the Estimated Parameters of Microbial Reduction Models

2014 ◽  
Vol 77 (8) ◽  
pp. 1372-1379 ◽  
Author(s):  
FRANCISCO GARCÉS-VEGA ◽  
BRADLEY P. MARKS
Keyword(s):  
Data Management ◽  
Management Practices ◽  
Limit Of Detection ◽  
Weibull Model ◽  
Microbial Reduction ◽  
Plate Count ◽  
Model Parameters ◽  
Negative Plate ◽  
Plate Counts ◽  
Log Linear

In the last 20 years, the use of microbial reduction models has expanded significantly, including inactivation (linear and nonlinear), survival, and transfer models. However, a major constraint for model development is the impossibility to directly quantify the number of viable microorganisms below the limit of detection (LOD) for a given study. Different approaches have been used to manage this challenge, including ignoring negative plate counts, using statistical estimations, or applying data transformations. Our objective was to illustrate and quantify the effect of negative plate count data management approaches on parameter estimation for microbial reduction models. Because it is impossible to obtain accurate plate counts below the LOD, we performed simulated experiments to generate synthetic data for both log-linear and Weibull-type microbial reductions. We then applied five different, previously reported data management practices and fit log-linear and Weibull models to the resulting data. The results indicated a significant effect (α = 0.05) of the data management practices on the estimated model parameters and performance indicators. For example, when the negative plate counts were replaced by the LOD for log-linear data sets, the slope of the subsequent log-linear model was, on average, 22% smaller than for the original data, the resulting model underpredicted lethality by up to 2.0 log, and the Weibull model was erroneously selected as the most likely correct model for those data. The results demonstrate that it is important to explicitly report LODs and related data management protocols, which can significantly affect model results, interpretation, and utility. Ultimately, we recommend using only the positive plate counts to estimate model parameters for microbial reduction curves and avoiding any data value substitutions or transformations when managing negative plate counts to yield the most accurate model parameters.

An Evaluation of Sampling Methods for the Detection of Escherichia coli and Salmonella on Turkey Carcasses

2005 ◽  
Vol 68 (1) ◽  
pp. 34-39 ◽  
Author(s):  
J. M. McEVOY ◽  
C. W. NDE ◽  
J. S. SHERWOOD ◽  
C. M. LOGUE
Keyword(s):  
Escherichia Coli ◽  
Breast Tissue ◽  
Sampling Methods ◽  
Skin Tissue ◽  
Plate Count ◽  
Microbiological Analysis ◽  
Bacterial Counts ◽  
E Coli ◽  
Plate Counts ◽  
Aerobic Plate Count

The efficacy of rinse, excision, and swab methods for the microbiological analysis of prechill turkey carcasses was investigated. Aerobic plate counts from a 50-cm2 area of the breast sampled by excision and by swabbing were compared. Escherichia coli and Salmonella recoveries were determined from turkeys sampled by a carcass rinse (CR), a modified rinse with the carcass supported in a swing (MCR), a two-site swab of 50 cm2 at the back and thigh (2S), a one-site swab of 50 cm2 beneath the wing (1S), a whole-carcass swab of the inner and outer carcass surface (WS), and excision of 25 g of neck skin tissue (NE). The effect of diluent volume (25, 50, and 100 ml) on E. coli counts from swab samples was also assessed. The aerobic plate count from breast tissue sampled by excision was greater than that by swabbing (P < 0.05). E. coli recoveries by the MCR method were similar to those by CR. E. coli counts from 1S and WS samples were higher when swabs were stomached in 50 rather than 25 ml of diluent (P < 0.05). For swabs stomached in 50 ml of diluent, E. coli recoveries by the MCR, 2S, 1S, and WS methods were similar. For swabs stomached in 50 ml of diluent, Salmonella recoveries by the WS and MCR methods were higher than those by the 2S and 1S methods. Excision was more effective than swabbing for obtaining total bacterial counts from reduced turkey carcass areas. Whole-carcass sampling by rinsing or swabbing is necessary for optimum Salmonella recovery. Sampling a reduced area of the carcass is sufficient for E. coli analysis.

scholarly journals The Efficacy of Lactic Acid Immersion as an Antimicrobial Intervention in Beef Sub-Primal Fabrication

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
D. E Casas
Keyword(s):  
Lactic Acid ◽  
Total Coliform ◽  
Food Microbiology ◽  
Plate Count ◽  
E Coli ◽  
Before And After ◽  
Plate Counts ◽  
Microbial Analysis ◽  
Aerobic Plate Count ◽  
Antimicrobial Intervention

ObjectivesTo perform an in-plant validation of a lactic acid immersion (2–5%) intervention in 6 different subprimals on the fabrication floor.Materials and MethodsSwab samples (n = 324) were taken before and after intervention application from six different processing lines. Each subprimal had a 500 cm2 area swabbed using sterile materials. Each repetition included 18 samples per line, 9 before and 9 after intervention, for a total of 108 samples per repetition. Swab samples were immediately chilled and shipped overnight to the TTU Food Microbiology laboratory for microbial analysis. Samples were stomached at 230 rpm for 30 s and for each subprimal, 3 individual samples were composited into one. Serial dilutions were performed and 1ml of each composite was plated onto Enterobacteriaceae, aerobic plate count, Escherichia coli and coliform Petrifilms in duplicate. Counts were transformed into LogCFU/cm2 and statistical analysis was performed to determine differences between before and after treatment samples with a 0.05 probability threshold.ResultsMicrobial counts of all four microorganisms evaluated were significantly reduced (P < 0.05) after the lactic acid immersion (2–5%) intervention application in subprimals. Total coliform counts before and after treatment were 0.31 and 0.06 LogCFU/cm2, respectively. Enterobacteriaceae counts in the subprimals were in average 0.40 LogCFU/cm2 before interventions and 0.06 LogCFU/cm2 after intervention application. Overall aerobic plate counts were 1.77 LogCFU/cm2 before intervention and 1.14 LogCFU/cm2 after intervention. Generic E. coli counts after intervention were lower than the detection limit (< 1 CFU/20 cm2).ConclusionBased on data collected, it is reasonable to conclude that the lactic acid immersion intervention is effective in reducing common microbial indicators on subprimals inside the fabrication floor, improving the safety of the product.

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