An Assessment of Escherichia coli O157:H7 Contamination Risks in Commercial Mayonnaise from Pasteurized Eggs and Environmental Sources, and Behavior in Low-pH Dressings

1995 ◽  
Vol 58 (10) ◽  
pp. 1059-1064 ◽  
Author(s):  
JOHN P. ERICKSON ◽  
JOSEPH W. STAMER ◽  
MARANDA HAYES ◽  
DENISE N. MCKENNA ◽  
LESLIE A. VAN ALSTINE
Keyword(s):  
Escherichia Coli ◽  
Health Hazard ◽  
Food Service ◽  
Low Ph ◽  
Escherichia Coli O157 ◽  
Contamination Sources ◽  
Wide Range ◽  
Processing Plants ◽  
Contamination Levels ◽  
Food Service Workers

An enterohemorrhaghic Escherichia coli O157:H7 (EHEC) outbreak in 1993 was epidemioiogically linked to commercial real mayonnaise. This study evaluated EHEC contamination risk during commercial mayonnaise and mayonnaise dressing production, and EHEC behavior in low-pH dressings. Two potential contamination sources, pasteurized liquid eggs and wet environmental areas, were surveyed for 4 months in three processing plants. One hundred eighty-eight egg lots and 114 environmental swabs were collected and analyzed for EHEC by enrichment and direct plating methods. All plant samples were EHEC negative. Commercial mayonnaise plants which use pasteurized eggs and employ effective good manufacturing practices (GMP) sanitation programs are unlikely EHEC harborage and contamination sources. Five commercial real-mayonnaise-based and reduced-calorie and/or fat mayonnaise dressings were inoculated with ≥6 log10 colony-forming units (CFU)/g EHEC contamination levels and stored at 25°C. The products contained a wide range of acetic acid, NaCl, and preservative levels, while pH varied from 3.21 to 3.94. Products below pH 3.6 rapidly inactivated EHEC, producing ≥7 log10 CFU/g decreases in ≤1 to ≤3 days. High EHEC lethality was also observed in the pH 3.94, egg white-mayonnaise dressing. Intact packages of commercial mayonnaise and mayonnaise dressings pose negligible EHEC contamination and health hazard risks. As with any food, consumers and food-service workers must use stringent hygienic practices to prevent microbial pathogen contamination during preparation, handling, and storage of mayonnaise-ingredient recipes such as chilled perishable salads and salad bar dressings.

Escherichia coli O157 Diversity with Respect to Survival during Drying on Concrete

2003 ◽  
Vol 66 (5) ◽  
pp. 780-786 ◽  
Author(s):  
S. M. AVERY ◽  
S. BUNCIC
Keyword(s):  
Escherichia Coli ◽  
Survival Rate ◽  
Phage Type ◽  
Survival Rates ◽  
Pfge Type ◽  
Meat Production ◽  
Escherichia Coli O157 ◽  
Production Chain ◽  
E Coli ◽  
Wide Range

Shiga toxin (Stx)–producing Escherichia coli O157 isolates (n = 123) were divided into groups according to origin, genotype (pulsed-field gel electrophoresis [PFGE] type, or ribotype), type of Stx produced, or phage type (PT). The survival rate ([number of CFU after 24 h of drying/number of CFU before drying] × 100) for each isolate was determined in triplicate after drying on concrete for 24.0 h. The overall mean survival rate among the 123 E. coli O157 isolates studied was 22.9%, but there was a wide range of responses to drying on concrete, with a minimum of 1.2% and a maximum of 61.9% of the initial inocula being recovered after drying. Among the groups, those isolates that originated from cases of human disease were, on average, significantly more sensitive (P < 0.001) to drying (with a mean survival rate of 15.3%) than isolates from the other three sources (with mean survival rates of 27.7, 26.0, and 22.9% for meats, bovine or ovine feces, and bovine hides, respectively). When the isolates were grouped by genotype, three of the PFGE types were, on average, significantly more resistant to drying than two other PFGE types were, and similarly, significant differences in average resistance to drying between groups of E. coli O157 with different ribotypes were seen. There were no differences between the abilities of isolates producing different Stxs (Stx 1 or Stx 1 and Stx 2) to survive drying. E. coli O157 isolates of PT4, PT21/28, and PT32 survived drying on concrete better than groups of other PTs did. Since the E. coli O157 isolates had various abilities to survive drying on concrete, drying could contribute to a kind of E. coli O157 natural selection along the meat chain. This possibility may have significant meat safety implications if a range of E. coli O157 isolates are simultaneously exposed to drying at any point along the meat production chain. Those E. coli O157 isolates that are more able to survive drying could be more likely to pass farther along the meat chain and ultimately reach consumers.

Influence of Sodium Chloride on Growth of Lactic Acid Bacteria and Subsequent Destruction of Escherichia coli O157:H7 during Processing of Lebanon Bologna

2001 ◽  
Vol 64 (8) ◽  
pp. 1145-1150 ◽  
Author(s):  
NAVEEN CHIKTHIMMAH ◽  
RAMASWAMY C. ANANTHESWARAN ◽  
ROBERT F. ROBERTS ◽  
EDWARD W. MILLS ◽  
STEPHEN J. KNABEL
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Low Ph ◽  
Escherichia Coli O157 ◽  
Quality Changes ◽  
E Coli ◽  
Fermented Product ◽  
Nacl Concentration ◽  
Different Levels

Due to undesirable quality changes, Lebanon bologna is often processed at temperatures that do not exceed 48.8°C (120°F). Therefore, it is important to study parameters that influence the destruction of Escherichia coli O157:H7 in Lebanon bologna. The objective of the present study was to determine the influence of curing salts (NaCl and NaNO2) on the destruction of E. coli O157:H7 during Lebanon bologna processing. Fermentation to pH 4.7 at 37.7°C reduced populations of E. coli O157:H7 by approximately 0.3 log10, either in the presence or absence of curing salts. Subsequent destruction of E. coli O157:H7 during heating of fermented product to 46.1°C was significantly reduced by the presence of 3.5% NaCl and 156 ppm NaNO2, compared to product without curing salts (P < 0.01). The presence of a higher level of NaCl (5%) in Lebanon bologna inhibited the growth of lactic acid bacteria (LAB), which yielded product with higher pH (~5.0) and significantly reduced the destruction of E. coli O157:H7 even further (P < 0.05). Lower concentrations of NaCl (0, 2.5%) yielded Lebanon bologna with higher LAB counts and lower pHs, compared to product with 5% NaCl. When lactic acid was used to adjust pH in product containing different levels of NaCl, it was determined that low pH was directly influencing destruction of E. coli O157:H7, not NaCl concentration.

10-Minute Assay for Detecting Escherichia coli O157:H7 in Ground Beef Samples Using Piezoelectric-Excited Millimeter-Size Cantilever Sensors

2007 ◽  
Vol 70 (7) ◽  
pp. 1670-1677 ◽  
Author(s):  
DAVID MARALDO ◽  
RAJ MUTHARASAN
Keyword(s):  
Escherichia Coli ◽  
Sample Preparation ◽  
Ground Beef ◽  
Low Ph ◽  
Frequency Change ◽  
Escherichia Coli O157 ◽  
Label Free ◽  
Cantilever Sensors ◽  
Ph Buffer ◽  
Phosphate Buffered Saline

We detected Escherichia coli O157:H7 (EC) at approximately 10 cells per ml in spiked ground beef samples in 10 min using piezoelectric-excited millimeter-size cantilever (PEMC) sensors. The composite PEMC sensors have a sensing area of 2mm2 and are prepared by immobilizing a polyclonal antibody specific to EC on the sensing surface. Ground beef (2.5 g) was spiked with EC at 10 to 10,000 cells per ml in phosphate-buffered saline (PBS). One milliliter of supernatant was removed from the blended samples and used to perform the detection experiments. The total resonant frequency change obtained for the inoculated samples was 138 ± 9, 735 ± 23, 2,603 ± 51, and 7,184 ± 606 Hz, corresponding to EC concentrations of 10, 100, 1,000, and 10,000 cells per ml, respectively. EC was detected in the sample solution within the first 10 min. The responses of the sensor to positive, negative, and buffer controls were 36 ± 6, 27 ± 2, and 2 ± 7 Hz, respectively. Verification of EC attachment was confirmed by low-pH buffer release (PBS-HCl, pH 2.2), microscopy, and second antibody EC binding postdetection. The results indicate that PEMC sensors can reliably detect EC at less than 10 cells per ml in 10 min without sample preparation and with label-free reagents.

scholarly journals Genotypic Analyses of Escherichia coli O157:H7 and O157 Nonmotile Isolates Recovered from Beef Cattle and Carcasses at Processing Plants in the Midwestern States of the United States

2001 ◽  
Vol 67 (9) ◽  
pp. 3810-3818 ◽  
Author(s):  
Genevieve A. Barkocy-Gallagher ◽  
Terrance M. Arthur ◽  
Gregory R. Siragusa ◽  
James E. Keen ◽  
Robert O. Elder ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
The United States ◽  
Escherichia Coli O157 ◽  
Genomic Fingerprinting ◽  
E Coli ◽  
Beef Processing ◽  
Processing Plants ◽  
Shiga Toxin Genes ◽  
Carcass Contamination ◽  
Animal Isolates

ABSTRACT Escherichia coli O157:H7 and O157 nonmotile isolates (E. coli O157) previously were recovered from feces, hides, and carcasses at four large Midwestern beef processing plants (R. O. Elder, J. E. Keen, G. R. Siragusa, G. A. Barkocy-Gallagher, M. Koohmaraie, and W. W. Laegreid, Proc. Natl. Acad. Sci. USA 97:2999–3003, 2000). The study implied relationships between cattle infection and carcass contamination within single-source lots as well as between preevisceration and postprocessing carcass contamination, based on prevalence. These relationships now have been verified based on identification of isolates by genomic fingerprinting.E. coli O157 isolates from all positive samples were analyzed by pulsed-field gel electrophoresis of genomic DNA after digestion with XbaI. Seventy-seven individual subtypes (fingerprint patterns) grouping into 47 types were discerned among 343 isolates. Comparison of the fingerprint patterns revealed three clusters of isolates, two of which were closely related to each other. Remarkably, isolates carrying both Shiga toxin genes and nonmotile isolates largely fell into specific clusters. Within lots analyzed, 68.2% of the postharvest (carcass) isolates matched preharvest (animal) isolates. For individual carcasses, 65.3 and 66.7% of the isolates recovered postevisceration and in the cooler, respectively, matched those recovered preevisceration. Multiple isolates were analyzed from some carcass samples and were found to include strains with different genotypes. This study suggests that mostE. coli O157 carcass contamination originates from animals within the same lot and not from cross-contamination between lots. In addition, the data demonstrate that most carcass contamination occurs very early during processing.

Oral Delivery Systems for Encapsulated Bacteriophages Targeted at Escherichia coli O157:H7 in Feedlot Cattle

2010 ◽  
Vol 73 (7) ◽  
pp. 1304-1312 ◽  
Author(s):  
K. STANFORD ◽  
T. A. McALLISTER ◽  
Y. D. NIU ◽  
T. P. STEPHENS ◽  
A. MAZZOCCO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Oral Delivery ◽  
Phage Therapy ◽  
Feedlot Cattle ◽  
Low Ph ◽  
Complete Loss ◽  
Escherichia Coli O157 ◽  
Polymer Encapsulation ◽  
E Coli ◽  
Oral Delivery Systems

Bacteriophages are natural predators of bacteria and may mitigate Escherichia coli O157:H7 in cattle and their environment. As bacteriophages targeted to E. coli O157:H7 (phages) lose activity at low pH, protection from gastric acidity may enhance efficacy of orally administered phages. Polymer encapsulation of four phages, wV8, rV5, wV7, and wV11, and exposure to pH 3.0 for 20 min resulted in an average 13.6% recovery of phages after release from encapsulation at pH 7.2. In contrast, untreated phages under similar conditions had a complete loss of activity. Steers (n = 24) received 1011 CFU of naladixic acid–resistant E. coli O157:H7 on day 0 and were housed in six pens of four steers. Two pens were control (naladixic acid–resistant E. coli O157:H7 only), and the remaining pens received polymer-encapsulated phages (Ephage) on days −1, 1, 3, 6, and 8. Two pens received Ephage orally in gelatin capsules (bolus; 1010 PFU per steer per day), and the remaining two pens received Ephage top-dressed on their feed (feed; estimated 1011 PFU per steer per day). Shedding of E. coli O157:H7 was monitored for 10 weeks by collecting fecal grab and hide swab samples. Acceptable activity of mixed phages at delivery to steers was found for bolus and feed, averaging 1.82 and 1.13 × 109 PFU/g, respectively. However, Ephage did not reduce shedding of naladixic acid–resistant E. coli O157:H7, although duration of shedding was reduced by 14 days (P < 0.1) in bolus-fed steers as compared with control steers. Two successful systems for delivery of Ephage were developed, but a better understanding of phage–E. coli O157:H7 ecology is required to make phage therapy a viable strategy for mitigation of this organism in feedlot cattle.

scholarly journals Detection of Escherichia coli O157:H7 and Salmonella enterica in Air and Droplets at Three U.S. Commercial Beef Processing Plants†

2012 ◽  
Vol 75 (12) ◽  
pp. 2213-2218 ◽  
Author(s):  
JOHN W. SCHMIDT ◽  
TERRANCE M. ARTHUR ◽  
JOSEPH M. BOSILEVAC ◽  
NORASAK KALCHAYANAND ◽  
TOMMY L. WHEELER
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Published Data ◽  
Escherichia Coli O157 ◽  
Liquid Droplets ◽  
Air Samples ◽  
E Coli ◽  
Beef Processing ◽  
Processing Plants ◽  
Plate Counts

Bacteria are known to be present in the air at beef processing plants, but published data regarding the prevalences of airborne Escherichia coli O157:H7 and Salmonella enterica are very limited. To determine if airborne pathogens were present in beef processing facilities, we placed sedimentation sponges at various locations in three commercial beef plants that processed cattle from slaughter through fabrication. For the 291 slaughter area air samples, E. coli O157:H7 was isolated from 15.8% and S. enterica from 16.5%. Of the 113 evisceration area air samples, E. coli O157:H7 was isolated from only one sample and S. enterica was not isolated from any sample. Pathogens were not isolated from any of the 87 air samples from fabrication areas. Pathogen prevalences, aerobic plate counts, and Enterobacteriaceae counts were highest for air samples obtained from locations near hide removal operations. The process of hide removal disperses liquid droplets, which may contact neighboring carcasses. Samples were obtained both from hide removal locations that were close enough to hide pullers to be contacted by droplets and from locations that were not contacted by droplets. Higher pathogen prevalences, aerobic plate counts, and Enterobacteriaceae counts were observed at locations with samples contacted by the hide removal droplets. We conclude that the hide removal processes likely introduce pathogens into the air via a dispersion of liquid droplets and that these droplets may be an underappreciated source of hide-to-carcass contamination.

Reduction of Escherichia coli O157:H7 on Produce by Use of Electrolyzed Water under Simulated Food Service Operation Conditions

2009 ◽  
Vol 72 (9) ◽  
pp. 1854-1861 ◽  
Author(s):  
PHILIPUS PANGLOLI ◽  
YEN-CON HUNG ◽  
LARRY R. BEUCHAT ◽  
C. HAROLD KING ◽  
ZHI-HUI ZHAO
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Fruits And Vegetables ◽  
Tap Water ◽  
Food Service ◽  
Escherichia Coli O157 ◽  
Electrolyzed Water ◽  
E Coli ◽  
Operation Conditions ◽  
Iceberg Lettuce

Treatment of fresh fruits and vegetables with electrolyzed water (EW) has been shown to kill or reduce foodborne pathogens. We evaluated the efficacy of EW in killing Escherichia coli O157:H7 on iceberg lettuce, cabbage, lemons, and tomatoes by using washing and/or chilling treatments simulating those followed in some food service kitchens. Greatest reduction levels on lettuce were achieved by sequentially washing with 14-A (amperage) acidic EW (AcEW) for 15 or 30 s followed by chilling in 16-A AcEW for 15 min. This procedure reduced the pathogen by 2.8 and 3.0 log CFU per leaf, respectively, whereas washing and chilling with tap water reduced the pathogen by 1.9 and 2.4 log CFU per leaf. Washing cabbage leaves for 15 or 30 s with tap water or 14-A AcEW reduced the pathogen by 2.0 and 3.0 log CFU per leaf and 2.5 to 3.0 log CFU per leaf, respectively. The pathogen was reduced by 4.7 log CFU per lemon by washing with 14-A AcEW and 4.1 and 4.5 log CFU per lemon by washing with tap water for 15 or 30 s. A reduction of 5.3 log CFU per lemon was achieved by washing with 14-A alkaline EW for 15 s prior to washing with 14-A AcEW for 15 s. Washing tomatoes with tap water or 14-A AcEW for 15 s reduced the pathogen by 6.4 and 7.9 log CFU per tomato, respectively. Application of AcEW using procedures mimicking food service operations should help minimize cross-contamination and reduce the risk of E. coli O157:H7 being present on produce at the time of consumption.

Augmentation of Killing of Escherichia coli O157 by Combinations of Lactate, Ethanol, and Low-pH Conditions

1999 ◽  
Vol 65 (3) ◽  
pp. 1308-1311 ◽  
Author(s):  
Sarah L. Jordan ◽  
Jayne Glover ◽  
Laura Malcolm ◽  
Fiona M. Thomson-Carter ◽  
Ian R. Booth ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Acid Tolerance ◽  
Low Ph ◽  
Exponential Phase ◽  
Escherichia Coli O157 ◽  
Cytoplasmic Ph ◽  
Ph Homeostasis ◽  
Acid Tolerant ◽  
Ph Conditions

ABSTRACT The acid tolerance of Escherichia coli O157:H7 strains can be overcome by addition of lactate, ethanol, or a combination of the two agents. Killing can be increased by as much as 4 log units in the first 5 min of incubation at pH 3 even for the most acid-tolerant isolates. Exponential-phase, habituated, and stationary-phase cells are all sensitive to incubation with lactate and ethanol. Killing correlates with disruption of the capacity for pH homeostasis. Habituated and stationary-phase cells can partially offset the effects of the lowering of cytoplasmic pH.

Effects of a Minimal Hide Wash Cabinet on the Levels and Prevalence of Escherichia coli O157:H7 and Salmonella on the Hides of Beef Cattle at Slaughter†

2007 ◽  
Vol 70 (5) ◽  
pp. 1076-1079 ◽  
Author(s):  
TERRANCE M. ARTHUR ◽  
JOSEPH M. BOSILEVAC ◽  
DAYNA M. BRICHTA-HARHAY ◽  
NORASAK KALCHAYANAND ◽  
STEVEN D. SHACKELFORD ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Beef Cattle ◽  
Limit Of Detection ◽  
Intervention Strategy ◽  
Medium Size ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Beef Processing ◽  
Before And After ◽  
Processing Plants

Harborage of Escherichia coli O157:H7 and Salmonella on animal hides at slaughter is the main source of beef carcass contamination during processing. Given this finding, interventions have been designed and implemented to target the hides of cattle following entry into beef processing plants. Previous interventions targeting hides have not been suitable for all beef processing plants because of cost and space restrictions. In this study, a hide wash cabinet was evaluated to determine whether it was more amenable to widespread use in the beef processing industry, especially for small and medium-size plants. Overall, 101 (35.1%) of 288 beef cattle hides sampled before entry into the hide wash cabinet harbored E. coli O157:H7 at or above the limit of detection (40 CFU/100 cm2). After passage through the hide wash cabinet, only 38 (13.2%) of 288 hides had E. coli O157:H7 levels ≥40 CFU/100 cm2. Before the hide wash cabinet, 50 (17%) of 288 hides harbored E. coli O157:H7 at levels above 100 CFU/100 cm2, with one sample as high as 20,000 CFU/100 cm2. In contrast, only 14 (5%) of 288 hides had E. coli O157:H7 levels above 100 CFU/100 cm2 after hide washing, with the highest being 2,000 CFU/100 cm2. These same trends also were found for Salmonella before and after hide washing. These results indicate that the hide wash cabinet described in this study was effective and should provide small and medium-size processing plants with an affordable hide wash intervention strategy.

Sign in / Sign up

Export Citation Format

Share Document