Use of light addressable potentiometric sensor (LAPS) to detect magnetically captured Escherichia coli O157:H7 in ground beef

2001 ◽  
Author(s):  
Shu-I Tu ◽  
Joseph Uknalis ◽  
Peter L. Irwin ◽  
Linda S. L. Yu
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Potentiometric Sensor ◽  
Escherichia Coli O157 ◽  
Light Addressable Potentiometric Sensor

Detection of Escherichia coli O157:H7 in ground beef using immunomagnetic separation and multiplex PCR

Food Control ◽  
2009 ◽  
Vol 20 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Belgin Sarimehmetoglu ◽  
Mihriban Hatun Aksoy ◽  
Naim Deniz Ayaz ◽  
Yildiz Ayaz ◽  
Ozlem Kuplulu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Escherichia Coli O157

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.

Thermal Inactivation of Escherichia coli O157: H7, Salmonella senftenberg, and Enzymes with Potential as Time-Temperature Indicators in Ground Beef

1997 ◽  
Vol 60 (5) ◽  
pp. 471-475 ◽  
Author(s):  
ALICIA ORTA-RAMIREZ ◽  
JAMES F. PRICE ◽  
YIH-CHIH HSU ◽  
GIRIDARAN J. VEERAMUTHU ◽  
JAMIE S. CHERRY-MERRITT ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Thermal Inactivation ◽  
Ground Beef ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Triose Phosphate ◽  
Beef Products ◽  
Z Value ◽  
D Values ◽  
Salmonella Senftenberg

The USDA has established processing schedules for beef products based on the destruction of pathogens. Several enzymes have been suggested as potential indicators of heat processing. However, no relationship between the inactivation rates of these enzymes and those of pathogenic microorganisms has been determined. Our objective was to compare the thermal inactivation of Escherichia coli O157:H7 and Salmonella senftenberg to those of endogenous muscle proteins. Inoculated and noninoculated ground beef samples were heated at four temperatures for predetermined intervals of time in thermal-death-time studies. Bacterial counts were determined and enzymes were assayed for residual activity. The D values for E. coli O157:H7 were 46.10, 6.44, 0.43, and 0.12 min at 53, 58, 63, and 68°C, respectively, with a z value of 5.60°C. The D values for S. senftenberg were 53.00, 15.17, 2.08, and 0.22 min at 53, 58, 63, and 68°C, respectively, with a z value of 6.24°C. Apparent D values at 53, 58, 63, and 68°C were 352.93, 26.31, 5.56, and 3.33 min for acid phosphatase; 6968.64, 543.48, 19.61, and 1.40 min for lactate dehydrogenase; and 3870.97, 2678.59, 769.23, and 42.92 min for peroxidase; with z values of 7.41,3.99, and 7.80°C, respectively. Apparent D values at 53, 58, 63, and 66°C were 325.03, 60.07, 3.07, and 1.34 min for phosphoglycerate mutase; 606.72, 89.86, 4.40, and 1.28 min for glyceraldehyde-3-phosphate dehydrogenase; and 153.06, 20.13, 2.25, and 0.74 min for triose phosphate isomerase; with z values of 5.18, 4.71, and 5.56°C, respectively. The temperature dependence of triose phosphate isomerase was similar to those of both E. coli O157 :H7 and S. senftenberg, suggesting that this enzyme could be used as an endogenous time-temperature indicator in beef products.

Viability of Acid-Adapted Escherichia coli O157:H7 in Ground Beef Treated with Acidic Calcium Sulfate

2004 ◽  
Vol 67 (3) ◽  
pp. 591-595 ◽  
Author(s):  
LARRY R. BEUCHAT ◽  
ALAN J. SCOUTEN
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Calcium Sulfate ◽  
Ground Beef ◽  
Storage Period ◽  
Acid Tolerance ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Acidic Environments ◽  
Subsequent Acid

The effects of lactic acid, acetic acid, and acidic calcium sulfate (ACS) on viability and subsequent acid tolerance of three strains of Escherichia coli O157:H7 were determined. Differences in tolerance to acidic environments were observed among strains, but the level of tolerance was not affected by the acidulant to which cells had been exposed. Cells of E. coli O157:H7 adapted to grow on tryptic soy agar acidified to pH 4.5 with ACS were compared to cells grown at pH 7.2 in the absence of ACS for their ability to survive after inoculation into ground beef treated with ACS, as well as untreated beef. The number of ACS-adapted cells recovered from ACS-treated beef was significantly (α = 0.05) higher than the number of control cells recovered from ACS-treated beef during the first 3 days of a 10-day storage period at 4°C, suggesting that ACS-adapted cells might be initially more tolerant than unadapted cells to reduced pH in ACS-treated beef. Regardless of treatment of ground beef with ACS or adaptation of E. coli O157:H7 to ACS before inoculating ground beef, the pathogen survived in high numbers.

Comparison of Rapid Enzyme-Linked Immunosorbent Assay and Immunomagnetic Separation Methods for Detection of Escherichia coli O157 in Fecal, Hide, Carcass, and Ground Beef Samples

2007 ◽  
Vol 70 (10) ◽  
pp. 2230-2234 ◽  
Author(s):  
T. W. THOMPSON ◽  
T. P. STEPHENS ◽  
G. H. LONERAGAN ◽  
M. F. MILLER ◽  
M. M. BRASHEARS
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Separation Method ◽  
Enzyme Linked Immunosorbent Assay ◽  
Escherichia Coli O157 ◽  
Perfect Agreement ◽  
Fecal Samples ◽  
E Coli ◽  
Beef Products

Rapid enzyme-linked immunosorbent assays (ELISAs) are approved for detection of Escherichia coli O157 in beef products. However, these kits have also been used in the industry to detect this pathogen on hides or in feces of cattle, although this use has not been validated. The objective of this study was to compare commercially available ELISAs (E. coli Now, Reveal, and VIP) with immunomagnetic separation along with selective media to detect E. coli O157 on hides, in feces, and in medium- and low-level-inoculated ground beef and carcasses (simulated by using briskets) samples. Naturally infected hide and fecal samples were subjected to both the immunomagnetic separation method and ELISAs for the detection of E. coli O157. Additionally, E. coli O157 inoculated and noninoculated ground beef and beef briskets were used to simulate meat and carcass samples. When comparing the detection results from the ELISAs (E. coli Now, Reveal, and VIP) to the immunomagnetic separation method, poor agreement was observed for fecal samples (kappa = 0.10, 0.02, and 0.03 for E. coli Now, Reveal, and VIP, respectively), and fair-to-moderate agreement was observed for hide samples (kappa = 0.30, 0.51, and 0.29 for E. coli Now, Reveal, and VIP, respectively). However, there was near-perfect agreement between the immunomagnetic separation method and ELISAs for ground beef (kappa = 1, 1, and 0.80 for E. coli Now, Reveal, and VIP, respectively) and brisket (kappa = 1, 1, and 1 for E. coli Now, Reveal, and VIP, respectively) samples. Assuming immunomagnetic separation is the best available method, these data suggest that the ELISAs are not useful in detecting E. coli O157 from hide or fecal samples. However, when ELISAs are used on ground beef and beef brisket samples they can be used with a high degree of confidence.

Carvacrol and Cinnamaldehyde Facilitate Thermal Destruction of Escherichia coli O157:H7 in Raw Ground Beef†

2008 ◽  
Vol 71 (8) ◽  
pp. 1604-1611 ◽  
Author(s):  
VIJAY K. JUNEJA ◽  
MENDEL FRIEDMAN
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Inactivation Kinetics ◽  
Escherichia Coli O157 ◽  
Internal Temperature ◽  
Circulating Water ◽  
Critical Control Points ◽  
Thermal Death ◽  
D Values ◽  
D Value

The heat resistance of a four-strain mixture of Escherichia coli O157:H7 in raw ground beef in both the absence and presence of the antimicrobials carvacrol and cinnamaldehyde was tested at temperatures ranging from 55 to 62.5°C. Inoculated meat packaged in bags was completely immersed in a circulating water bath, cooked for 1 h to an internal temperature of 55, 58, 60, or 62.5°C, and then held for predetermined lengths of time ranging from 210 min at 55°C to 5 min at 62.5°C. The surviving bacteria were enumerated by spiral plating onto tryptic soy agar overlaid with sorbitol MacConkey agar. Inactivation kinetics of the pathogens deviated from first-order kinetics. D-values (time for the bacteria to decrease by 90%) in the control beef ranged from 63.90 min at 55°C to 1.79 min at 62.5°C. D-values determined by a logistic model ranged from 43.18 min (D1, the D-value of a major population of surviving cells) and 89.84 min (D2, the D-value of a minor subpopulation) at 55°C to 1.77 (D1) and 0.78 min (D2) at 62.5°C. The thermal death times suggested that to achieve a 4-D reduction, contaminated processed ground beef should be heated to an internal temperature of 60°C for at least 30.32 min. Significantly increased sensitivity to heat (P < 0.05) was observed with the addition and/or increasing levels of carvacrol or cinnamaldehyde from 0.5 to 1.0%. The observed thermal death times may facilitate the design of acceptance limits at critical control points for ground beef at lower times and temperatures of heating.

Distribution Patterns of Escherichia coli O157:H7 in Ground Beef Produced by a Laboratory-Scale Grinder†

2002 ◽  
Vol 65 (12) ◽  
pp. 1894-1902 ◽  
Author(s):  
ROLANDO A. FLORES ◽  
MARK L. TAMPLIN
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Distribution Patterns ◽  
Small Scale ◽  
Escherichia Coli O157 ◽  
Inoculum Level ◽  
E Coli ◽  
Specific Distribution ◽  
Low Levels ◽  
G Prior

This study determined the distribution patterns of Escherichia coli O157:H7 in ground beef when a contaminated beef trim was introduced into a batch of uncontaminated beef trims prior to grinding in a small-scale laboratory grinder. A beef trim (15.3 ± 2 g) was inoculated with a rifampicin-resistant strain of E. coli O157:H7 (E. coli O157:H7rif) and introduced into a stream of noncontaminated beef (322 ± 33 g) prior to grinding. Seven inoculum levels (6, 5, and 4 total log CFU [high]; and 3, 2, 1, and 0 total log CFU [low]) were studied in triplicate. E. coli O157:H7rif was not detected in 3.1 to 43% of the ground beef inoculated with the high levels or in 3.4 to 96.9% of the ground beef inoculated with the low levels. For all inoculum levels studied, the five ground beef fractions (each 7.8 ± 0.6 g) with the highest pathogen levels accounted for 59 to 100% of the total pathogens detected. For all inoculum levels, there was a linear relationship between the quantity of ground beef containing E. coli O157:H7rif and the inoculum level. The quantity of E. coli O157:H7rif in the beef remaining in the grinder was proportional to the inoculum level and was related to the location in the grinder. Different components of the grinder accumulated E. coli O157:H7rif in different quantities, with the most significant accumulation being in the nut (collar) that attaches the die to the blade. This study determined specific distribution patterns of E. coli O157:H7rif after the grinding of a contaminated beef trim along with uncontaminated trims, and the results indicate that the grinding operation should be regarded as a means of distribution of microbial contamination in risk analyses of ground beef operations.

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