Enumeration of Escherichia coli O157 in Outbreak-Associated Gouda Cheese Made with Raw Milk

2015 ◽  
Vol 78 (9) ◽  
pp. 1733-1737 ◽  
Author(s):  
ALEXANDER GILL ◽  
DENISE OUDIT
Keyword(s):  
Escherichia Coli ◽  
Raw Milk ◽  
Most Probable Number ◽  
Prolonged Storage ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
E Coli ◽  
Aging Period ◽  
Gouda Cheese ◽  
Cheese Products

In this article, we discuss the enumerative analysis for Escherichia coli O157 in two raw milk Gouda cheese products (A and B), implicated in an outbreak of 29 cases of E. coli O157:H7 illness that occurred across Canada in 2013. Samples were enumerated for E. coli O157 by most probable number (MPN) over a period of 30 to 60 days after the end of the outbreak. Samples (55.55 g) of product A (n = 14) were analyzed at 146 to 180 days postproduction. E. coli O157 was isolated from six samples at 19.9 to 44.6 MPN/kg. The E. coli O157 concentration of product A estimated from the results of all 14 samples was 9.5 MPN/kg. Samples (55.55 g) of product B (n = 20) were analyzed at 133 to 149 days postproduction. E. coli O157 was isolated from four samples at 19.9 MPN/kg. The E. coli O157 concentration of product B estimated from the results of all 20 samples was 3.7 MPN/kg. Analysis of a 305-g sample of product A (n = 1) stored at 4°C until 306 days postproduction revealed that the E. coli O157 concentration had declined to 3.6 MPN/kg. E. coli O157 could not be isolated from 555-g samples of product B (n = 5) after 280 days postproduction. The physicochemical parameters (pH, water activity, percent moisture, and percent salt) of both cheese products were found to be in the normal range for this type of product. The results of this study demonstrate that E. coli O157 could not replicate during storage at 4°C in the products tested but was capable of survival following aging and prolonged storage. This indicates that, if contaminated, the minimum 60-day aging period, which is required for raw milk Gouda cheeses, is not sufficient in all cases to ensure that the product does not contain viable cells of E. coli O157. The results also indicate that samples sizes greater than 100 g may be required to reliably detect E. coli O157 in cheese products associated with outbreaks.

Outbreak of Escherichia coli O157:H7 Infections Linked to Aged Raw Milk Gouda Cheese, Canada, 2013

2017 ◽  
Vol 81 (2) ◽  
pp. 325-331 ◽  
Author(s):  
Andrea Currie ◽  
Eleni Galanis ◽  
Pedro A. Chacon ◽  
Regan Murray ◽  
Lynn Wilcott ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Primary Source ◽  
Raw Milk ◽  
Core Sample ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Aging Period ◽  
Dairy Plant ◽  
Gouda Cheese ◽  
Canadian Provinces

ABSTRACT Between 12 July and 29 September 2013, 29 individuals in five Canadian provinces became ill following infection with the same strain of Escherichia coli O157:H7 as defined by molecular typing results. Five case patients were hospitalized, and one died. Twenty-six case patients (90%) reported eating Gouda cheese originating from a dairy plant in British Columbia. All of the 22 case patients with sufficient product details available reported consuming Gouda cheese made with raw milk; this cheese had been produced between March and July 2013 and was aged for a minimum of 60 days. The outbreak strain was isolated from the implicated Gouda cheese, including one core sample obtained from an intact cheese wheel 83 days after production. The findings indicate that raw milk was the primary source of the E. coli O157:H7, which persisted through production and the minimum 60-day aging period. This outbreak is the third caused by E. coli O157:H7 traced to Gouda cheese made with raw milk in North America. These findings provide further evidence that a 60-day ripening period cannot ensure die-off of pathogens that might be present in raw milk Gouda cheese after production and have triggered an evaluation of processing conditions, physicochemical parameters, and options to mitigate the risk of E. coli O157:H7 infection associated with raw milk Gouda cheese produced in Canada.

scholarly journals Escherichia coli O157:H7 in Drin Prevalence of Escherichia coli O157:H7 in Drink from Different Food Premises in Kota Samarahan Sarawak

2019 ◽  
Vol 2 (2) ◽  
pp. a13-19
Author(s):  
ELEXSON NILLIAN ◽  
AMIZA NUR ◽  
DIYANA NUR ◽  
AMIRAH ZAKIRAH ◽  
GRACE BEBEY
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Coliform Bacteria ◽  
Most Probable Number ◽  
Plain Water ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
E Coli ◽  
Preventive Actions ◽  
Stx1 Gene

Contamination of drinks with E. coli O157:H7 served in food premises such as restaurants can cause haemorrhagic colitis and haemolytic uremic syndrome to humans. The presence or absence of faecal pathogen was demonstrated using coliform group as indicator microorganisms. Therefore, this study was conducted to detect the presence of E. coli O157:H7 in drinking water from food restaurant premise in Kota Samarahan and Kuching to ensure safe and potable drinking water is served to the consumer. A total of thirty (n=30) drink samples including six types of each of the samples are cold plain water, iced tea, iced milo, syrup and iced milk tea. Most Probable Number (MPN) procedure was used in this study to enumerate the MPN values of coliform bacteria in each drink collected. A total of 53.33% (16/30) of the drink samples showed positive E. coli detection. Then, the PCR assay showed 6.25% (one out of 16 isolates) samples were positive and carried stx1 gene produced by E. coli O157:H7 in iced milo sample types. This study showed the drinks collected from food premises was contaminated with faecal contamination, which was not safe to drink by the consumer. Therefore, preventive actions should be taken to prevent foodborne illness outbreak in future

Comparison of the SimPlate Coliform and Escherichia coli Test with Petrifilm, Three-Tube MPN, and VRBA + MUG Methods for Enumerating Coliforms and E. coli in Food

1998 ◽  
Vol 61 (4) ◽  
pp. 444-449 ◽  
Author(s):  
D. E. TOWNSEND ◽  
R. L. IRVING ◽  
A. NAQUI
Keyword(s):  
Escherichia Coli ◽  
Correlation Coefficients ◽  
Raw Milk ◽  
Food Samples ◽  
Coliform Bacteria ◽  
Most Probable Number ◽  
Additional Food ◽  
Suitable Alternative ◽  
Probable Number ◽  
E Coli

SimPlate for coliforms and Escherichia coli (CEc) is a new method for the detection and quantification of coliforms and E. coli in food. Internal validation of the method was carried out at IDEXX Laboratories (Westbrook, ME) with 180 food samples representing a variety of different food matrices and compared against three-tube MPN (most probable number), VRBA (violet red bile agar) + MUG, and Petrifilm (E. coli count) methods. SimPlate CEc was highly correlated with each of these methods for the quantification of coliform bacteria (r ≥ 0.90). An insignificant number of food samples were found to contain E. coli; therefore, no meaningful correlation data could be generated. Four hundred forty-four additional food samples were tested at five collaborating laboratories for the presence of coliforms and E. coli using SimPlate CEc and either VRBA + MUG or Petrifilm (E. coli count). Regression analysis of data from SimPlate for CEc versus Petrifilm E. coli count plates generated correlation coefficients (r) of at least 0.89 for total coliforms and at least 0.90 for generic E. coli. Correlation coefficients between SimPlate for CEc and VRBA + MUG data were at least 0.90 for coliforms and at least 0.86 for E. coli. SimPlate for CEc demonstrated better recovery of E. coli than Petrifilm when high populations of bacteria were present. E. coli was not detected in 20 of 50 (40%) raw milk samples tested by the Petrifilm method due to the presence of interfering coliform and noncoliform bacteria. It is concluded that SimPlate for CEc is a suitable alternative for determining numbers of coliform bacteria and E. coli in food.

An Investigation of Escherichia coli O157 Contamination of Cattle during Slaughter at an Abattoir

2005 ◽  
Vol 68 (3) ◽  
pp. 451-457 ◽  
Author(s):  
NARELLE FEGAN ◽  
GLEN HIGGS ◽  
PAUL VANDERLINDE ◽  
PATRICIA DESMARCHELIER
Keyword(s):  
Escherichia Coli ◽  
Oral Cavity ◽  
Immunomagnetic Separation ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
Fecal Samples ◽  
E Coli ◽  
Cell Counts ◽  
Carcass Contamination

The extent of contamination with Escherichia coli O157 was determined for 100 cattle during slaughter. Samples from 25 consecutively slaughtered cattle from four unrelated groups were collected from the oral cavity, hide, rumen, feces after evisceration, and pre- and postchill carcass. Ten random fecal samples were collected from the pen where each group of animals was held at the abattoir. E. coli O157 was detected using automated immunomagnetic separation (AIMS), and cell counts were determined using a combination of most probable number (MPN) and AIMS. E. coli O157 was isolated from 87 (14%) of the 606 samples collected, including 24% of 99 oral cavity samples, 44% of 100 hides, 10% of 68 fecal samples collected postevisceration, 6% of 100 prechill carcass swabs, and 15% of 40 fecal samples collected from holding pens. E. coli O157 was not isolated from rumen or postchill carcass samples. E. coli O157 was isolated from at least one sample from each group of cattle tested, and the prevalence in different groups ranged from less than 1 to 41%. The numbers of E. coli O157 differed among the animals groups. The group which contained the highest fecal (7.5 × 105 MPN/g) and hide (22 MPN/cm2) counts in any individual animal was the only group in which E. coli O157 was isolated from carcasses, suggesting a link between the numbers of E. coli O157 present and the risk of carcass contamination. Processing practices at this abattoir were adequate for minimizing contamination of carcasses, even when animals were heavily contaminated with E. coli O157.

Prevalence of Escherichia coli O157:H7 and Salmonella on Inshell California Walnuts

2015 ◽  
Vol 78 (8) ◽  
pp. 1547-1553 ◽  
Author(s):  
GORDON R. DAVIDSON ◽  
JOHN C. FRELKA ◽  
MAI YANG ◽  
THOMAS M. JONES ◽  
LINDA J. HARRIS
Keyword(s):  
Escherichia Coli ◽  
Confidence Interval ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
E Coli ◽  
Annual Prevalence

Inshell walnuts collected from California walnut handlers over four harvests were evaluated for the presence of Escherichia coli O157:H7 and Salmonella. E. coli O157:H7 was not detected in any of 2,903 375-g samples evaluated in 2011, 2012, and 2013 (<0.034% prevalence; 95% confidence interval [CI], 0 to 0.13%). Salmonella was not isolated from any of the 935 samples in 2010 (100 g evaluated; <0.11% prevalence; 95% CI, 0 to 0.41%) but was isolated from 2 of 905 (375 g; 0.22% prevalence; 95% CI, 0.061 to 0.80%), 1 of 998 (375 g; 0.10% prevalence; 95% CI, 0.018 to 0.56%), and 1 of 1,000 (375 g; 0.10% prevalence; 95% CI, 0.018 to 0.56%) samples in 2011, 2012, and 2013, respectively, for an average annual prevalence of 0.14% (375 g; 95% CI, 0.054 to 0.35%). The levels of Salmonella in positive samples determined by a modified most-probable-number (MPN) method were estimated to be 0.32 to 0.42 MPN/100 g (95% CI, 0.045 to 3.6 MPN/100 g).

Bactericidal Effect of Sodium Chlorate on Escherichia coli O157:H7 and Salmonella Typhimurium DT104 in Rumen Contents In Vitro

2000 ◽  
Vol 63 (8) ◽  
pp. 1038-1042 ◽  
Author(s):  
ROBIN C. ANDERSON ◽  
SANDRA A. BUCKLEY ◽  
LEON F. KUBENA ◽  
LARRY H. STANKER ◽  
ROGER B. HARVEY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nitrate Reductase ◽  
Salmonella Typhimurium ◽  
Bactericidal Effect ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
E Coli ◽  
Respiratory Nitrate Reductase

Escherichia coli O157:H7 and Salmonella Typhimurium DT104 are important foodborne pathogens affecting the beef and dairy industries and strategies are sought to rid these organisms from cattle at slaughter. Both pathogens possess respiratory nitrate reductase that also reduces chlorate to the lethal chlorite ion. Because most anaerobes lack respiratory nitrate reductase, we hypothesized that chlorate may selectively kill E. coli O157:H7 and Salmonella Typhimurium DT104 but not potentially beneficial anaerobes. In support of this hypothesis, we found that concentrations of E. coli O157:H7 and Salmonella Typhimurium DT104 were reduced from approximately 1,000,000 colony forming units (CFU) to below our level of detection (≤10 CFU) following in vitro incubation (24 h) in buffered ruminal contents (pH 6.8) containing 5 mM added chlorate. In contrast, chlorate had little effect on the most probable number (mean ± SD) of total culturable anaerobes (ranging from 9.9 ± 0.72 to 10.7 ± 0.01 log10 cells/ml). Thus, chlorate was bactericidal to E. coli O157:H7 and Salmonella Typhimurium DT104 but not to potentially beneficial bacteria. The bactericidal effect of chlorate was concentration dependent (less at 1.25 mM) and markedly affected by pH (more bactericidal at pH 6.8 than pH 5.6).

Environmental Dust Exposure as a Factor Contributing to an Increase in Escherichia coli O157 and Salmonella Populations on Cattle Hides in Feedyards

2008 ◽  
Vol 71 (10) ◽  
pp. 2078-2081 ◽  
Author(s):  
M. F. MILLER ◽  
G. H. LONERAGAN ◽  
D. D. HARRIS ◽  
K. D. ADAMS ◽  
J. C. BROOKS ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Positive Sample ◽  
Dust Exposure ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
Airborne Dust ◽  
E Coli ◽  
Dust Generation ◽  
The Impact

A study was conducted to determine the impact of exposure to dust in the cattle load-out area in feedyards on pathogen contamination of cattle hides. A total of 250 cattle hides were sampled during summer and fall months, which are associated with elevated prevalence of Escherichia coli O157 in West Texas. Animals were removed from their home pens and restrained in a chute and sampled prior to exposure to dust generated as a result of a simulated loading exercise. The cattle hides were sampled again after exposure to the loading dust to determine total numbers of pathogens on cattle hides on leaving their home pen (before loading) and on cattle hides after exposure to the dust in the loading area. Air and dirt samples from the home pens and the cattle load-out area were also collected. The presence of E. coli O157 and Salmonella was determined in all the samples, and when a positive sample was identified, the total numbers of these bacteria present were enumerated. The total numbers of pathogens increased after dust exposure; Salmonella counts increased from 1.09 log most probable number (MPN)/cm2 to 1.74 log MPN/cm2 after exposure, and E. coli O157 counts increased from 0.80 to 2.35 log MPN/cm2 after sampling. E. coli O157 and Salmonella were recovered from the air samples during dust generation at 6.66 and 11.1%, respectively. Salmonella and E. coli O157 prevalence was not changed and was not associated with the exposure to the dust. Results indicate airborne dust generated as a result of cattle movement and loading could be an important determining factor in total numbers of pathogens recovered on cattle hides.

Development and Validation of a Most-Probable-Number–Immunomagnetic Separation Methodology of Enumerating Escherichia coli O157 in Cattle Feces

2007 ◽  
Vol 70 (5) ◽  
pp. 1072-1075 ◽  
Author(s):  
T. P. STEPHENS ◽  
G. H. LONERAGAN ◽  
W. E. CHANEY ◽  
L. A. BRANHAM ◽  
M. M. BRASHEARS
Keyword(s):  
Escherichia Coli ◽  
Immunomagnetic Separation ◽  
Feedlot Cattle ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
Direct Plating ◽  
Fecal Samples ◽  
E Coli ◽  
The Difference

A method to validate enumeration of Escherichia coli O157 in fecal samples from feedlot cattle was developed in these studies. Due to background flora, bovine fecal sample enumeration cannot be performed by simple direct plating techniques. Known quantities of E. coli O157:H7 were inoculated into feces, and populations were determined by direct plating of the cocktail (studies 1, 2, and 3) and manure and cocktail (studies 4 and 5) mixtures and compared with a most-probable-number (MPN)–immunomagnetic separation (IMS) method. The three-tube MPN combined preenrichment in gram-negative broth with confirmation using IMS. Five separate enumeration studies (study 1, sterile feces inoculated with 102 E. coli O157:H7 per g; study 2, nonsterile feces inoculated with 103 E. coli O157:H7 per g; study 3, nonsterile feces inoculated with 101 E. coli O157:H7 per g; study 4, sterile feces inoculated with 104 streptomycin-resistant E. coli O157:H7 per g; and study 5, sterile feces inoculated with 102 streptomycin-resistant E. coli O157:H7 per g) were conducted. These studies were performed to determine the precision, accuracy, and specificity at low and high levels of pathogen contamination in feces, using direct plating compared with the MPN-IMS methodology tested. There was an overall difference (P < 0.01) between direct plating and MPN-IMS methodologies, but this difference was biologically negligible due to the difference in least-squares means (0.29 ± 0.10) being so low. The direct plating and MPN-IMS methods were correlated (r = 0.93). These results suggest that using the MPN-IMS procedures is an effective method of estimating E. coli O157 populations in naturally infected bovine fecal samples.

Enumeration of Escherichia coli O157:H7 in Outbreak-Associated Beef Patties

2016 ◽  
Vol 79 (7) ◽  
pp. 1266-1268 ◽  
Author(s):  
ALEXANDER GILL ◽  
GEORGE HUSZCZYNSKI
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Cross Contamination ◽  
Probable Number ◽  
E Coli ◽  
Beef Patties ◽  
Selective Agar ◽  
Agar Media

ABSTRACT An outbreak of five cases of Escherichia coli O157 infection that occurred in Canada in 2012 was linked to frozen beef patties seasoned with garlic and peppercorn. Unopened retail packs of beef patties from the implicated production lot were recovered and analyzed to enumerate E. coli O157, other E. coli strains, and total coliforms. E. coli O157 was not recovered by direct enumeration on selective agar media. E. coli O157 in the samples was estimated at 3.1 most probable number per 140 g of beef patty, other E. coli was 11 CFU/g, and coliforms were 120 CFU/g. These results indicate that the presence of E. coli O157 in ground beef at levels below 0.1 CFU/g may cause outbreaks. However, the roles of temperature abuse, undercooking, and cross-contamination in amplifying the risk are unknown.

Inactivation of Escherichia coli O157:H7 on Romaine Lettuce When Inoculated in a Fecal Slurry Matrix

2017 ◽  
Vol 80 (5) ◽  
pp. 792-798 ◽  
Author(s):  
Jennifer A. Chase ◽  
Edward R. Atwill ◽  
Melissa L. Partyka ◽  
Ronald F. Bond ◽  
David Oryang
Keyword(s):  
Escherichia Coli ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Romaine Lettuce ◽  
Probable Number ◽  
Inoculum Concentration ◽  
E Coli ◽  
Log Reduction ◽  
Salinas Valley ◽  
Sampling Event

ABSTRACT A field trial was conducted in July 2011 to quantify the inactivation rate of Escherichia coli O157:H7 when mixed with fecal slurry and applied to romaine lettuce leaves. Lettuce was grown under commercial conditions in Salinas Valley, CA. One-half milliliter of rabbit fecal slurry, containing 6.3 × 107 CFU of E. coli O157:H7, was inoculated onto the upper (adaxial) surface of a lower leaf on 240 heads of lettuce within 30 min after a 2.5-h irrigation event. Forty-eight romaine lettuce heads were collected per event at 2.5 h (day 0.1), 19.75 h (day 0.8), 43.25 h (day 1.8), 67.25 h (day 2.8), and 91.75 h (day 3.8) postinoculation and were analyzed for the concentration of E. coli O157:H7 (Ct). E. coli O157:H7 was detected on 100% of collected heads in concentrations ranging from 340 to 3.40 × 1010 most probable number (MPN) per head. Enumeration data indicate substantial growth of E. coli O157:H7 postinoculation (2.5 h), leading to elevated concentrations, 1 to 3 log above the starting inoculum concentration (Co). By the end of the 92-h trial, we observed a net 0.8-log mean reduction of E. coli O157:H7 compared with Co; however, after accounting for the substantial bacterial growth, there was an overall 2.3-log reduction by the final sampling event (92 h). On the basis of two different regression models that used either the raw data for Ct or log-transformed values of Ct/Co during the period 2.5 to 91.75 h postinoculation, there was an estimated 76 to 80% reduction per day in bacterial counts; however, more accurate predictions of MPN per head of lettuce were generated by using non–log-transformed values of Ct. This study provides insight into the survival of E. coli O157:H7 transferred via splash from a contaminated fecal source onto produce during irrigation. Moreover, these findings can help generate inactivation times following a potential contamination incident.

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