E. coli O157:H7 in Frozen Raw Ground Beef Patties

2002 ◽  
pp. 313-332
Author(s):  
Keyword(s):  
Ground Beef ◽  
E Coli ◽  
Beef Patties

scholarly journals Lessons from a large outbreak of Escherichia coli O157[ratio ]H7 infections: insights into the infectious dose and method of widespread contamination of hamburger patties

1999 ◽  
Vol 122 (2) ◽  
pp. 185-192 ◽  
Author(s):  
J. TUTTLE ◽  
T. GOMEZ ◽  
M. P. DOYLE ◽  
J. G. WELLS ◽  
T. ZHAO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Most Probable Number ◽  
Strong Argument ◽  
Probable Number ◽  
Infectious Dose ◽  
E Coli ◽  
Beef Patties ◽  
Large Outbreak ◽  
Microbiological Testing

Between November 1992 and February 1993, a large outbreak of Escherichia coli O157[ratio ]H7 infections occurred in the western USA and was associated with eating ground beef patties at restaurants of one fast-food chain. Restaurants that were epidemiologically linked with cases served patties produced on two consecutive dates; cultures of recalled ground beef patties produced on those dates yielded E. coli O157[ratio ]H7 strains indistinguishable from those isolated from patients, confirming the vehicle of illness. Seventy-six ground beef patty samples were cultured quantitatively for E. coli O157[ratio ]H7. The median most probable number of organisms was 1·5 per gram (range, <0·3–15) or 67·5 organisms per patty (range, <13·5–675). Correlation of the presence of E. coli O157[ratio ]H7 with other bacterial indicators yielded a significant association between coliform count and the presence of E. coli O157[ratio ]H7 (P=0·04). A meat traceback to investigate possible sources of contamination revealed cattle were probably initially colonized with E. coli O157[ratio ]H7, and that their slaughter caused surface contamination of meat, which once combined with meat from other sources, resulted in a large number of contaminated ground beef patties. Microbiological testing of meat from lots consumed by persons who became ill was suggestive of an infectious dose for E. coli O157[ratio ]H7 of fewer than 700 organisms. These findings present a strong argument for enforcing zero tolerance for this organism in processed food and for markedly decreasing contamination of raw ground beef. Process controls that incorporate microbiological testing of meat may assist these efforts.

Bacteriological Evaluation of Retail Ground Beef, Frozen Beef Patties, and Cooked Hamburger

1977 ◽  
Vol 40 (6) ◽  
pp. 378-381 ◽  
Author(s):  
C. L. DUITSCHAEVER ◽  
D. H. BULLOCK ◽  
D. R. ARNOTT
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Fast Food ◽  
Ground Beef ◽  
Frozen Ground ◽  
E Coli ◽  
Beef Patties ◽  
Plate Counts ◽  
Bacteriological Evaluation ◽  
G 28

A total of 108 samples of fresh refrigerated ground beef, 99 samples of frozen hamburger patties, and 107 fried hamburgers, purchased from retail stores and fast-food outlets in Ontario, were analyzed for their bacteriological quality. About 44% of non-frozen ground beef samples had aerobic plate counts exceeding 50 million/g; 50 of 108 samples (46.3%) contained Staphylococcus aureus and 46 of these 50 samples (88%) exceeded 1000 organisms/g; 43 of 108 samples were positive for Escherichia coli with 38 samples (88.4%) exceeding 500 organisms/g. About 19% of frozen hamburger patties had aerobic plate counts in excess of 10 million/g; 93 of 99 samples (93.9%) contained S. aureus with 83 of these samples (89.3%) exceeding 1000 organisms/g; 28 of 99 samples were positive for E. coli with 7 of these samples (25%) exceeding 500 organisms/g. About 96.3% of fried hamburger samples had aerobic plate counts of less than 10,000/g.

Survival of Escherichia coli O157:H7 in Ground-Beef Patties during Storage at 2, −2, 15 and then −2°C, and −20°C†

1999 ◽  
Vol 62 (11) ◽  
pp. 1243-1247 ◽  
Author(s):  
SUSAN E. ANSAY ◽  
KIM A. DARLING ◽  
CHARLES W. KASPAR
Keyword(s):  
Escherichia Coli ◽  
Frozen Storage ◽  
Ground Beef ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Control Strain ◽  
Single Strain ◽  
E Coli ◽  
Beef Patties ◽  
Significant Difference

The survival of Escherichia coli O157:H7 and of a nonpathogenic control strain of E. coli was monitored in raw ground beef that was stored at 2°C for 4 weeks, −2°C for 4 weeks, 15°C for 4 h and then −2°C for 4 weeks, and −20°C. Irradiated ground beef was inoculated with one E. coli control strain or with a four-strain cocktail of E. coli O157:H7 (ca. 105 CFU/g), formed into patties (30 to 45 g), and stored at the appropriate temperature. The numbers of the E. coli control strain decreased by 1.4 log10 CFU/g, and pathogen numbers declined 1.9 log10 CFU/g when patties were stored for 4 weeks at 2°C. When patties were stored at −2°C for 4 weeks, the numbers of the E. coli control strain and the serotype O157:H7 strains decreased 2.8 and 1.5 log10 CFU/g, respectively. Patties stored at 15°C for 4 h prior to storage at −2°C for 4 weeks resulted in 1.6 and 2.7 log10–CFU/g reduction in the numbers of E. coli and E. coli O157:H7, respectively. Storage of retail ground beef at 15°C for 4 h (tempering) did not result in increased numbers of colony forming units per gram, as determined with violet red bile, MRS lactobacilli, and plate-count agars. Frozen storage (−20°C) of ground-beef patties that had been inoculated with a single strain of E. coli resulted in approximately a 1 to 2 log10–CFU/g reduction in the numbers of the control strain and individual serotype O157:H7 strains after 1 year. There was no significant difference between the survival of the control strain and the O157:H7 strains, nor was there a difference between O157:H7 strains. These data demonstrate that tempering of ground-beef patties prior to low-temperature storage accelerated the decline in the numbers of E. coli O157:H7.

Inactivation of Escherichia coli O157:H7 in Ground Beef by Single-Cycle and Multiple-Cycle High-Pressure Treatments

2008 ◽  
Vol 71 (4) ◽  
pp. 811-815 ◽  
Author(s):  
PILAR MORALES ◽  
JAVIER CALZADA ◽  
MARTA ÁVILA ◽  
MANUEL NUÑEZ
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Shear Force ◽  
Ground Beef ◽  
Escherichia Coli O157 ◽  
Single Cycle ◽  
E Coli ◽  
Beef Patties ◽  
Texture Parameters ◽  
Multiple Cycle

The effect of single- and multiple-cycle high-pressure treatments on the survival of Escherichia coli CECT 4972, a strain belonging to the O157:H7 serotype, in ground beef was investigated. Beef patties were inoculated with 107 CFU/g E. coli O157:H7, and held at 4°C for 20 h before high-pressure treatments. Reduction of the E. coli O157:H7 population by single-cycle treatments at 400 MPa and 12°C ranged from 0.82 log CFU/g for a 1-min cycle to 4.39 log CFU/g for a 20-min cycle. Multiple-cycle treatments were very effective, with four 1-min cycles at 400 MPa and 12°C reducing the E. coli O157:H7 population by 4.38 log CFU/g, and three 5-min cycles by 4.96 log CFU/g. The color parameter L* increased significantly with high-pressure treatments in the interior and the exterior of beef patties, whereas a* decreased in the interior, and b* increased in the exterior—changes that might diminish consumer acceptance of the product. Kramer shear force and energy were generally higher in pressurized than in control ground beef. Maximum values for these texture parameters, which corresponded to tougher patties, were reached after one 10-min cycle in the case of single-cycle treatments or two 5-min cycles in the case of multiple-cycle treatments. High-pressure treatments had no significant effect on Warner-Bratzler shear force.

Comparison of the Microbial Quality of Ground Beef and Ground Beef Patties from Internet and Local Retail Markets†

2009 ◽  
Vol 72 (8) ◽  
pp. 1722-1726 ◽  
Author(s):  
S. PAO ◽  
M. R. ETTINGER
Keyword(s):  
Ground Beef ◽  
Foodborne Illness ◽  
Microbial Quality ◽  
Frozen Ground ◽  
Retail Markets ◽  
E Coli ◽  
Beef Patties ◽  
Beef Products ◽  
Careful Handling

This study evaluated the microbial quality of ground beef and ground beef patties sold at local (Virginia) and Internet (U.S.) retail markets. A total of 152 ground beef products, consisting of locally purchased raw ground beef (LRG) and frozen beef patties (LFP) and Internet-procured frozen ground beef (IFG) and frozen beef patties (IFP), were tested. Results showed that LFP had significantly lower levels of aerobic mesophiles, psychrotrophs, and coliforms than LRG, IFG, and IFP. Furthermore, IFG had greater numbers of Escherichia coli than LRG and LFP. No sample was contaminated with E. coli O157: H7, but one duplicate set of summer LFP samples contained Salmonella. Listeria spp. were present in 25 and 29% of samples from local and Internet markets, respectively. About 5.0, 11.1, 10.5, and 7.9% of LRG, LFP, IFG, and IFP samples were contaminated with L. monocytogenes. This study identified differences in microbial quality between local and Internet products. Careful handling and thorough cooking of ground beef products, regardless of market source, are recommended to prevent foodborne illness.

Heat Resistance of Escherichia coli O157:H7 in a Nutrient Medium and in Ground Beef Patties as Influenced by Storage and Holding Temperatures

1996 ◽  
Vol 59 (3) ◽  
pp. 230-237 ◽  
Author(s):  
TIMOTHY C. JACKSON ◽  
MARGARET D. HARDIN ◽  
GARY R. ACUFF
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Heat Resistance ◽  
Elevated Temperatures ◽  
Potential Temperature ◽  
Ground Beef ◽  
Escherichia Coli O157 ◽  
Commercial Preparation ◽  
E Coli ◽  
Beef Patties

Stationary-phase cultures of Escherichia coli O157:H7 were inoculated into tryptic soy broth, sealed in vials, and stored at −18°C for 1, 8, and 15 days, or 3 or 15°C for 3, 6, and 9 h. Thermal resistance was determined at 55°C. Each storage treatment was repeated with additional holding at 23 or 30°C for 1, 2, 3, or 4 h prior to heating to simulate potential temperature abuse during handling. Cultures under treatments enabling the growth of E. coli O157:H7 were generally more heat sensitive than those held at temperatures which restricted growth or enabled growth to stationary phase. Cultures stored frozen (−18°C) without holding at elevated temperatures had greater heat resistance than those stored under refrigeration (3°C) or at 15°C. Subsequent holding of frozen cultures at 23 or 30°C resulted in a decrease in heat resistance. To determine whether these responses would be observed under typical commercial preparation procedures, ground beef patties were inoculated with E. coli O157:H7 and stored at 3 or 15°C for 9 h or at −18°C for 8 d and then held at 21 or 30°C for 0 or 4 h. Patties were grilled to an internal temperature of 54.4°C (130°F), 62.8°C (145°F), or 68.3°C (155°F). Cultures were most resistant in frozen patties, while cultures in patties stored at 15°C were the most heat sensitive. Holding patties at 21 or 30°C prior to grilling resulted in increased sensitivity. Storage and holding temperatures similar to those encountered in food service may influence the ability of E. coli O157:H7 to survive heat treatments.

Fate of Shiga Toxin–Producing O157:H7 and Non-O157:H7 Escherichia coli Cells within Refrigerated, Frozen, or Frozen Then Thawed Ground Beef Patties Cooked on a Commercial Open-Flame Gas or a Clamshell Electric Grill†

2013 ◽  
Vol 76 (9) ◽  
pp. 1500-1512 ◽  
Author(s):  
JOHN B. LUCHANSKY ◽  
ANNA C. S. PORTO-FETT ◽  
BRADLEY A. SHOYER ◽  
JOHN PHILLIPS ◽  
VIVIAN CHEN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Initial Level ◽  
Ground Beef ◽  
High Fat ◽  
E Coli ◽  
Final Level ◽  
Beef Patties ◽  
Escherichia Coli Cells ◽  
Fat Level

Both high-fat and low-fat ground beef (percent lean:fat = ca. 70:30 and 93:7, respectively) were inoculated with a 6-strain cocktail of non-O157:H7 Shiga toxin–producing Escherichia coli (STEC) or a five-strain cocktail of E. coli O157:H7 (ca. 7.0 log CFU/g). Patties were pressed (ca. 2.54 cm thick, ca. 300 g each) and then refrigerated (4°C, 18 to 24 h), or frozen (−18°C, 3 weeks), or frozen (−18°C, 3 weeks) and then thawed (4°C for 18 h or 21°C for 10 h) before being cooked on commercial gas or electric grills to internal temperatures of 60 to 76.6°C. For E. coli O157:H7, regardless of grill type or fat level, cooking refrigerated patties to 71.1 or 76.6°C decreased E. coli O157:H7 numbers from an initial level of ca. 7.0 log CFU/g to a final level of ≤1.0 log CFU/g, whereas decreases to ca. 1.1 to 3.1 log CFU/g were observed when refrigerated patties were cooked to 60.0 or 65.5°C. For patties that were frozen or freeze-thawed and cooked to 71.1 or 76.6°C, E. coli O157:H7 numbers decreased to ca. 1.7 or ≤0.7 log CFU/g. Likewise, pathogen numbers decreased to ca. 0.7 to 3.7 log CFU/g in patties that were frozen or freeze-thawed and cooked to 60.0 or 65.5°C. For STEC, regardless of grill type or fat level, cooking refrigerated patties to 71.1 or 76.6°C decreased pathogen numbers from ca. 7.0 to ≤0.7 log CFU/g, whereas decreases to ca. 0.7 to 3.6 log CFU/g were observed when refrigerated patties were cooked to 60.0 or 65.5°C. For patties that were frozen or freeze-thawed and cooked to 71.1 or 76.6°C, STEC numbers decreased to a final level of ca. 1.5 to ≤0.7 log CFU/g. Likewise, pathogen numbers decreased from ca. 7.0 to ca. 0.8 to 4.3 log CFU/g in patties that were frozen or freeze-thawed and cooked to 60.0 or 65.5°C. Thus, cooking ground beef patties that were refrigerated, frozen, or freeze-thawed to internal temperatures of 71.1 and 76.6°C was effective for eliminating ca. 5.1 to 7.0 log CFU of E. coli O157:H7 and STEC per g.

Survival of Escherichia coli O157:H7 after Freezing and Thawing in Ground Beef Patties

1998 ◽  
Vol 61 (9) ◽  
pp. 1181-1183 ◽  
Author(s):  
JAY R. SAGE ◽  
STEVEN C. INGRAM
Keyword(s):  
Escherichia Coli ◽  
Microwave Heating ◽  
Ground Beef ◽  
Escherichia Coli O157 ◽  
Strain Atcc ◽  
E Coli ◽  
Population Decrease ◽  
Beef Patties ◽  
Recovered Strain ◽  
Agar Method

Survival of Escherichia coli O157:H7 strains QA 326, and ATCC 43889,43894, and 43895 after freezing (−20°C, 24 h) and thawing (4°C for 12 h, 23°C for 3 h, or microwave heating of 700 W for 120 s) in ground beef patties was determined by reference most probable number (MPN), hydrophobic grid membrane filter SD-39 agar, and sorbitol MacConkey agar (SMA) spread-plating methods. Populations decreased from 0.62 to 2.52 log10 CFU/g, with the extent varying significantly by strain. Strain QA 326 populations almost always decreased the most, up to 1.87 log10 CFU/g more than the least sensitive strain. Microwave heating was the most lethal thawing treatment for strain QA 326, and 4°C thawing was the most lethal treatment for strain ATCC 43894. Thawing treatments varied in relative lethality for the other two strains. For strain QA 326 (4°C and microwave thaw treatments) and strain ATCC 43889 (4 and 23°C thawing), the enumeration method significantly affected a population decrease. The SD-39 agar method best recovered strain QA 326 while the SD-39 agar method and the reference MPN method best recovered strain ATCC 43889 after 4 and 23°C thawing, respectively. The greatest difference in population decrease measured by any two methods was 0.58 log10 CFU/g. Results showed (i) a wide range in freeze-thaw sensitivity among E. coli O157:H7 strains, (ii) no thawing method had consistently and significantly greater lethality, and (iii) the reference MPN, SD-39 agar, and SMA methods differed little in ability to enumerate E. coli O157:H7.

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.

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