scholarly journals Influence of raw meat natural background flora on growth of Escherichia coli O157: H7 in ground beef

1999 ◽  
Vol 30 (3) ◽  
pp. 272-277 ◽  
Author(s):  
Susana M.I. Saad ◽  
Bernadette D.G.M. Franco
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Putida ◽  
Room Temperature ◽  
Foodborne Pathogen ◽  
Meat Products ◽  
Ground Beef ◽  
Escherichia Coli O157 ◽  
Natural Background ◽  
Raw Meat ◽  
Cultural Methods

Escherichia coli O157:H7 is a foodborne pathogen of increasing importance. It has been involved in several threatening outbreaks, most of them associated with meat products. In this study, the influence of some bacteria from the natural background flora of raw meat over E.coli O157:H7 in ground beef stored under refrigeration and at room temperature was evaluated. Different levels of E.coli O157:H7 (101-102, 103-104 and 106-107 CFU/g), inoculated in ground beef samples, were challenged with strains of non-pathogenic E.coli, Pseudomonas putida or Leuconostoc sp. Growth of the pathogen was monitored using standard cultural methods and an ELISA-type rapid method. Non-pathogenic E.coli, Pseudomonas putida and Leuconostoc sp. did not affect growth of E.coli O157:H7 in ground beef, both under refrigeration and at room temperature. Based on these findings, the low occurrence of E.coli O157:H7 in raw meat may not be attributed to antagonistic effects of bacteria from the natural background flora.

Validation of Time and Temperature Values as Critical Limits for the Control of Escherichia coli O157:H7 during the Production of Fresh Ground Beef

2006 ◽  
Vol 69 (8) ◽  
pp. 1978-1982 ◽  
Author(s):  
J. E. MANN ◽  
M. M. BRASHEARS
Keyword(s):  
Escherichia Coli ◽  
Room Temperature ◽  
Hazard Analysis ◽  
Control Point ◽  
Ground Beef ◽  
Escherichia Coli O157 ◽  
Meat Processing ◽  
E Coli ◽  
Critical Control Point ◽  
Critical Limits

In order to provide beef processors with valuable data to validate critical limits set for temperature during grinding, a study was conducted to determine Escherichia coli O157:H7 growth at various temperatures in raw ground beef. Fresh ground beef samples were inoculated with a cocktail mixture of streptomycin-resistant E. coli O157:H7 to facilitate recovery in the presence of background flora. Samples were held at 4.4, 7.2, and 10°C, and at room temperature (22.2 to 23.3°C) to mimic typical processing and holding temperatures observed in meat processing environments. E. coli O157:H7 counts were determined by direct plating onto tryptic soy agar with streptomycin (1,000 μg/ml), at 2-h intervals over 12 h for samples held at room temperature. Samples held under refrigeration temperatures were sampled at 4, 8, 12, 24, 48, and 72 h. Less than one log of E. coli O157:H7 growth was observed at 48 h for samples held at 10°C. Samples held at 4.4 and 7.2°C showed less than one log of E. coli O157:H7 growth at 72 h. Samples held at room temperature showed no significant increase in E. coli O157:H7 counts for the first 6 h, but increased significantly afterwards. These results illustrate that meat processors can utilize a variety of time and temperature combinations as critical limits in their hazard analysis critical control point plans to minimize E. coli O157:H7 growth during the production and storage of ground beef.

Occurrence and Characterization of Escherichia coli O157 and Other Serotypes in Raw Meat Products in Morocco

2008 ◽  
Vol 71 (10) ◽  
pp. 2082-2086 ◽  
Author(s):  
LUCIANO BENEDUCE ◽  
GIUSEPPE SPANO ◽  
ARI Q. NABI ◽  
FRANCESCO LAMACCHIA ◽  
SALVATORE MASSA ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Susceptibility Testing ◽  
Meat Products ◽  
Molecular Techniques ◽  
Escherichia Coli O157 ◽  
Raw Meat ◽  
E Coli ◽  
Meat Samples ◽  
The City

In this study, 100 raw meat samples were collected from 15 local Moroccan butcheries in five different areas of the city of Rabat during a period of 4 months. Overall, 7 of 15 butcheries from three areas of the city yielded strains of Escherichia coli O157. Single isolates from 9 (9%) of 100 raw meat samples were biochemically and serologically confirmed as E. coli O157. Using molecular techniques, two strains were positive for the Shiga toxin, with two additional strains containing an attaching-effacing gene. All potentially virulent serotypes isolated from these meat samples showed distinct pulsed-field gel electrophoresis profiles. Based on antibiotic susceptibility testing, more than 70% of the isolates were resistant to ampicillin and clavulanic acid–amoxicillin. Moreover, one strain was resistant to more than three antibiotics. Our study represents the first survey of E. coli O157 and related serotypes in raw meat products in Morocco.

Comparative Evaluation of a Phage Protein Ligand Assay with Real-Time PCR and a Reference Method for the Detection of Escherichia coli O157:H7 in Raw Ground Beef and Trimmings

2011 ◽  
Vol 74 (1) ◽  
pp. 6-12 ◽  
Author(s):  
F. SAVOYE ◽  
P. FENG ◽  
C. ROZAND ◽  
M. BOUVIER ◽  
A. GLEIZAL ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Ground Beef ◽  
Reference Method ◽  
Enterohemorrhagic Escherichia Coli ◽  
Detection Methods ◽  
Escherichia Coli O157 ◽  
Rt Pcr ◽  
Raw Meat ◽  
E Coli

Enterohemorrhagic Escherichia coli O157:H7 is an important pathogen associated with infections caused by consumption of undercooked raw meat. Sensitive and rapid detection methods for E. coli O157:H7 are essential for the meat industry to ensure a safe meat supply. This study was conducted to compare the sensitivity of the VIDAS ultraperformance E. coli test (ECPT UP) with a noncommercial real-time (RT) PCR method and the U.S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) reference method for detecting E. coli O157:H7 in raw ground beef. Optimal enrichment times and the efficacy of testing different types of raw meat, either as individual samples (25 g) or as composites (375 g), were examined. For 25-g samples of each type of raw ground beef tested, 6 h of enrichment was sufficient for both the VIDAS ECPT UP and RT-PCR methods, but for 375-g samples, 24 h of enrichment was required. Both the VIDAS ECPT UP and RT-PCR methods produced results similar to those obtained with the USDA-FSIS reference method after 18 to 24 h of enrichment. The primer specificity of the RT-PCR assay and the highly specific phage ligand used in the VIDAS ECPT UP for target recognition enabled the detection of low levels of E. coli O157:H7 in 25 g of various types of raw ground beef. The tests also allowed the detection of E. coli O157:H7 in composite raw ground beef and trimmings in samples of up to 375 g.

Distribution of Escherichia coli O157:H7 in Beef Processed in a Table-Top Bowl Cutter†

2004 ◽  
Vol 67 (2) ◽  
pp. 246-251 ◽  
Author(s):  
ROLANDO A. FLORES
Keyword(s):  
Escherichia Coli ◽  
Meat Products ◽  
Ground Beef ◽  
Distribution Patterns ◽  
Escherichia Coli O157 ◽  
Salmonella Spp ◽  
Particle Size Reduction ◽  
Operational Conditions ◽  
E Coli ◽  
Beef Processing

Beef-processing equipment can be contaminated with pathogens such as Escherichia coli O157:H7 and Salmonella spp. The bowl cutter has wide application in particle-size reduction and blending of meat products. This study was undertaken to determine (i) the distribution patterns of E. coli O157:H7 in equipment components and ground beef produced with a table-top bowl cutter under different operational conditions and (ii) the likelihood that pathogen contamination can be transferred to subsequent batches after a batch of beef contaminated with E. coli O157:H7 has been processed in the same bowl cutter. A beef trim (44.6 ± 29.5 g) inoculated with 2 log CFU of an E. coli O157:H7 mutant strain resistant to rifampicin ( E. coli O157:H7rif) was fed by hand into an uncontaminated beef-trim batch under two different batch sizes (2 and 4 kg), three processing times (60, 120, and 240 s), and two feeding modes (running and stoppage fed). There were no significant differences (P ≥ 0.05) among all the treatments for the averages of the counts of E. coli O157:H7rif distributed in the ground beef. Regardless of the processing time and the method used to feed the beef trims into the bowl cutter, the whole batch and the following subsequent batch became contaminated when previously contaminated beef was processed. Areas of the bowl cutter most likely to be contaminated with E. coli O157:H7 were (i) the material left on the top of the comb/knife guard and (ii) the knife. Material that overflowed the bowl cutter, when processing the batch with E. coli O157:H7rif, contaminated the equipment surroundings. A Pearson V probability distribution function was determined to describe the distribution of pathogenic organisms in the ground beef, a distribution that can also be applied when conducting process risk analyses on mixing-particle reduction operations for beef trims.

Validation of Low-Volume Enrichment Protocols for Detection of Escherichia coli O157 in Raw Ground Beef Components, Using Commercial Kits

2009 ◽  
Vol 72 (3) ◽  
pp. 669-673 ◽  
Author(s):  
IMTIAZ AHMED ◽  
DENISE HUGHES ◽  
IAN JENSON ◽  
TASS KARALIS
Keyword(s):  
Escherichia Coli ◽  
Cost Savings ◽  
Ground Beef ◽  
Escherichia Coli O157 ◽  
Enrichment Broth ◽  
E Coli ◽  
Cultural Methods ◽  
Beef Products ◽  
Low Levels ◽  
Commercial Kits

Testing of beef destined for use in ground beef products for the presence of Escherichia coli O157:H7 has become an important cornerstone of control and verification activities within many meat supply chains. Validation of the ability of methods to detect low levels of E. coli O157:H7 is critical to confidence in test systems. Many rapid methods have been validated against standard cultural methods for 25-g samples. In this study, a number of previously validated enrichment broths and commercially available test kits were validated for the detection of low numbers of E. coli O157:H7 in 375-g samples of raw ground beef component matrices using 1 liter of enrichment broth (large-sample:low-volume enrichment protocol). Standard AOAC International methods for 25-g samples in 225 ml of enrichment broth, using the same media, incubation conditions, and test kits, were used as reference methods. No significant differences were detected in the ability of any of the tests to detect low levels of E. coli O157:H7 in samples of raw ground beef components when enriched according to standard or large-sample:low-volume enrichment protocols. The use of large-sample:low-volume enrichment protocols provides cost savings for media and logistical benefits when handling and incubating large numbers of samples.

Evaluation of a Phosphate To Control Pathogen Growth in Fresh and Processed Meat Products

1996 ◽  
Vol 59 (4) ◽  
pp. 356-359 ◽  
Author(s):  
LISA M. FLORES ◽  
SUSAN S. SUMNER ◽  
DIANNE L. PETERS ◽  
ROGER MANDIGO
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Foodborne Pathogens ◽  
Meat Products ◽  
Ground Beef ◽  
Processed Meat ◽  
Escherichia Coli O157 ◽  
Pork Sausage ◽  
E Coli

The efficacy of a phosphate blend, Bekaplus MSP, to inhibit the growth of foodborne pathogens in fresh or processed meat products was studied. The following products and challenge microorganisms were tested: ground beef, Escherichia coli O157:H7; linked smoked sausage, Salmonella typhimurium and L. monocytogenes; cured smoked ham, S. typhimurium and L. monocytogenes; and fresh pork sausage, E. coli O157:H7. All the products were prepared with or without 0.5% phosphate, individually inoculated with the challenge microorganism (103CFU/g of meat), and stored at either 4, 12, or 20°C. There was minimal or no effect of the phosphate blend on the growth of L. monocytogenes or S. typhimurium. The temperature of storage had a significant effect (P < 0.05) on the population of E. coli O157:H7 in ground beef and fresh pork sausage with phosphate. However, the presence of phosphate in the ground beef had no effect (P > 0.05) on E. coli O157:H7, but the presence of phosphate in the fresh pork sausage had a significant effect (P < 0.05) on controlling E. coli O157:H7. These results indicate that this phosphate blend could be used in fresh pork sausage to help inhibit the growth of E. coli O157:H7.

scholarly journals Comparison of the BAX for Screening/E. coli O157:H7 Method with Conventional Methods for Detection of Extremely Low Levels of Escherichia coli O157:H7 in Ground Beef

1998 ◽  
Vol 64 (11) ◽  
pp. 4390-4395 ◽  
Author(s):  
Jennifer L. Johnson ◽  
Cheryl L. Brooke ◽  
Scott J. Fritschel
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Escherichia Coli O157 ◽  
Important Food ◽  
E Coli ◽  
Cultural Methods ◽  
Food Borne ◽  
Highly Sensitive ◽  
Low Levels ◽  
Very High

ABSTRACT Escherichia coli O157:H7 is an important food-borne pathogen. Often E. coli O157:H7 is difficult to detect, because it is present sporadically at very low levels together with very high levels of competitor organisms which can be difficult to distinguish phenotypically. Cultural methods are time-consuming and give variable results in the detection of E. coli O157:H7. This study examined the performance of BAX for Screening/E. coli O157:H7, a new rapid method for the detection of E. coli O157:H7, against traditional and improved cultural methods and an immunodiffusion assay. All cultural methods demonstrated inadequacy in detecting the presence of E. coliO157:H7 in inoculated samples. The limitations of these cultural methods further complicate evaluation of screening methodologies. The BAX for Screening/E. coli O157:H7 assay outperformed the other methods, with a detection rate of 96.5%, compared to 39% for the best cultural method and 71.5% for the immunodiffusion method. The BAX for Screening/E. coli O157:H7 assay proved to be a rapid, highly sensitive test for the detection of low levels ofE. coli O157:H7 in ground beef.

Survival of Escherichia coli O157:H7 in Ground Beef Jerky Assessed on Two Plating Media

1998 ◽  
Vol 61 (1) ◽  
pp. 11-13 ◽  
Author(s):  
JUDY A. HARRISON ◽  
MARK A. HARRISON ◽  
RUTH ANN ROSE
Keyword(s):  
Escherichia Coli ◽  
Meat Products ◽  
Ground Beef ◽  
Processed Meat ◽  
Escherichia Coli O157 ◽  
Bacterial Cells ◽  
Salmonella Spp ◽  
Suitable Alternative ◽  
E Coli ◽  
Beef Jerky

Recent outbreaks of food-borne illness due to Salmonella spp. in beef jerky and Escherichia coli O157:H7 in venison jerky, coupled with the fact that a variety of preparation methods and drying procedures abound, raise concern over the safety of processed meat products made in the home. The potential of injured bacterial cells to regain the ability to cause illness is a particular threat with pathogens such as E. coli O157:H7, which is believed to have a low infectious dose. This study examined the efficacy of various methods of jerky preparation in reducing populations of E. coli O157:H7 in ground beef jerky and compared the recovery rate of E. coli O157:H7 on two selective plating media, modified sorbitol MacConkey agar (MSMA) and modified eosin methylene blue agar (MEMB). Populations of E. coli O157:H7 in both heated and unheated samples exhibited a greater decline during drying when a nitrite and salt cure mix was added during jerky preparation. When recovery of E. coli O157:H7 on MSMA and MEMB was compared, a trend toward slightly higher recovery rates with MEMB was observed. On the basis of these results, MEMB is a suitable alternative to MSMA for the recovery of E. coli O157:H7 from heated and dried meat samples similar to beef jerky.

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