Difference between Escherichia coli O157:H7 and non-pathogenic E. coli: Survival and growth in seasonings

1999 ◽  
Vol 88 (5) ◽  
pp. 574-576 ◽  
Author(s):  
Kumio Yokoigawa ◽  
Akiko Takikawa ◽  
Hiroyasu Kawai
Keyword(s):  
Escherichia Coli ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Survival And Growth

Fate of Escherichia coli O157:H7 in the Presence of Indigenous Microorganisms on Commercially Packaged Baby Spinach, as Impacted by Storage Temperature and Time†

2009 ◽  
Vol 72 (10) ◽  
pp. 2038-2045 ◽  
Author(s):  
YAGUANG LUO ◽  
QIANG HE ◽  
JAMES L. McEVOY ◽  
WILLIAM S. CONWAY
Keyword(s):  
Escherichia Coli ◽  
Product Quality ◽  
Elevated Temperatures ◽  
Storage Temperature ◽  
Escherichia Coli O157 ◽  
Indigenous Microorganisms ◽  
E Coli ◽  
Psychrotrophic Bacteria ◽  
Survival And Growth

This study investigated the effect of storage temperature and time on the survival and growth of Escherichia coli O157:H7, the growth of indigenous microorganisms, and the changes in product quality of packaged baby spinach. Commercial packages of spinach within 2 days of processing were cut open at one end, sprayed with fine mists of E. coli O157:H7 inoculum, resealed, and then stored at 1, 5, 8, and 12°C for 12 days until their labeled best-if-used-by dates. Microbial enumeration and product quality evaluation were conducted on day(s) 0, 3, 6, 9, and 12 postinoculation. Spinach held at 12°C supported significant (P < 0.001) E. coli O157:H7 growth, with a 1.0-log CFU/g increase within 3 days postinoculation, which was followed by additional growth during continued storage. E. coli O157:H7 grew slowly when held at 8°C, with a significant (P < 0.01) level of growth reached after 6 days of storage. However, on products held at 1 and 5°C, E. coli O157:H7 populations declined significantly (P < 0.01 and P < 0.001, respectively) within 3 days of storage. Aerobic mesophilic bacteria, psychrotrophic bacteria, and yeast and mold populations increased significantly at all storage temperatures, with more growth on products held at elevated temperatures. Product quality scores remained high within the first 6 days of storage, with a sharp decline noted on samples held at 12°C on day 9. Results suggest that E. coli O157:H7 can grow significantly on commercially packaged spinach held at 8°C or above before significant product quality deterioration occurs.

Effectiveness of Salt, pH, and Diacetyl as Inhibitors for Escherichia coli O157:H7 in Dairy Foods Stored at Refrigeration Temperatures

1998 ◽  
Vol 61 (9) ◽  
pp. 1098-1102 ◽  
Author(s):  
R. GURAYA ◽  
J. F. FRANK ◽  
A. N. HASSAN
Keyword(s):  
Escherichia Coli ◽  
Skim Milk ◽  
Cottage Cheese ◽  
Escherichia Coli O157 ◽  
Dairy Foods ◽  
E Coli ◽  
Dry Milk ◽  
Survival And Growth ◽  
Sour Cream ◽  
Temperature Levels

The behavior of Escherichia coli O157:H7 inoculated in 10% rehydrated nonfat dry milk adjusted to pH levels between 3.8 and 5.4 with lactic acid, salt levels of 0 to 6%, and diacetyl levels of 0, 5, and 10 μg/g was determined at 4 and 12°C. Cell populations were determined by surface plating on tryptic soy agar after 7 and 35 days of incubation. Survival was also determined using retad cultured dairy products. E. coli O157:H7 did not survive in skim milk at pH 3.8 and was reduced by 3 log cycles at pH 4.1, regardless of salt, diacetyl, and temperature levels. At pH levels above 4.4, survival was observed at lower salt concentrations for up to 35 days at both 12 and 4°C. The organism grew (up to a 2.2-log increase) at pH 5.0 at 2% salt levels after 35 days of storage at 12°C but not at 4°C. Diacetyl at a concentration of 10 ppm had no effect on survival and growth. In all but one case, E. coli O157:H7 was inactivated in yogurt, sour cream, and buttermilk at a rate similar to or greater than what was consistent with the acidified skim milk data. Also consistent with the skim milk data, growth occurred in two of the three cottage cheese samples at 12°C after 7 days but not after 35 days or at 4°C, when a 1- to 2-log decline was observed.

Survival and Growth of Escherichia coli O157:H7 in Unpasteurized and Pasteurized Milk

1997 ◽  
Vol 60 (6) ◽  
pp. 610-613 ◽  
Author(s):  
GUODONG WANG ◽  
TONG ZHAO ◽  
MICHAEL P. DOYLE
Keyword(s):  
Escherichia Coli ◽  
Microbial Population ◽  
Antagonistic Activity ◽  
Escherichia Coli O157 ◽  
Pasteurized Milk ◽  
E Coli ◽  
Milk Samples ◽  
Unpasteurized Milk ◽  
Uremic Syndrome ◽  
Survival And Growth

Escherichia coli O157:H7, which causes hemorrhagic colitis and hemolytic uremic syndrome, has been responsible for several outbreaks associated with consumption of unpasteurized and improperly processed pasteurized milk, and yogurt. Studies were conducted to determine the survival and growth characteristics of this pathogen in unpasteurized milk and pasteurized milk (3.5% fat, 2% fat, skim) at 5,8, 15, and 22°C for up to 28 days. Two levels of inocula (103 and 105 CFU/ml) of a mixture of five nalidixic acid-resistant E. coli O157:H7 strains were used. E. coli O157:H7 did not grow at 5°C and decreased by 1.6 to 2.0 log CFU/ml in 28 days. Growth occurred at 8°C, with an approximately 1- to 2-log CFU/ml increase within the first 4 days. About a 3- to 5-log CFU/ml increase in E. coli O157:H7 populations was observed at 15°C within the first 3 days. In 3 pasteurized milk samples, E. coli O157:H7 continued to grow to populations of greater than 1.0 × 108 CFU/ml at day 7 and remained constant during the remainder of the incubation period. At 22°C, the pH decreased rapidly to less than 4.0 within 4 days and E. coli O157:H7 decreased to undetectable populations within 14 days. E. coli O157:H7 grew more slowly (P < 0.01) in unpasteurized milk, which had a higher initial microbial population, than in pasteurized milks at 8, 15, or 22°C, likely because of antagonistic activity from preexisting bacteria. No significant differences (P> 0.05) in survival or growth of E. coli O157:H7 were observed among the pasteurized milk samples, regardless of fat concentration, at all temperatures throughout the study. The data indicate that temperature abuse during shipping and handling can result in significant growth of E. coli O157:H7. Holding milk at ≤5°C is recommended to prevent growth of this pathogen.

Survival and Growth of Escherichia coli O157:H7 in Roast Beef and Salami after Exposure to an Alkaline Cleaner

2004 ◽  
Vol 67 (10) ◽  
pp. 2107-2116 ◽  
Author(s):  
MANAN SHARMA ◽  
GLENNER M. RICHARDS ◽  
LARRY R. BEUCHAT
Keyword(s):  
Escherichia Coli ◽  
Storage Period ◽  
Escherichia Coli O157 ◽  
Mold Growth ◽  
Wild Type ◽  
Macconkey Agar ◽  
E Coli ◽  
Different Temperatures ◽  
Survival And Growth ◽  
Roast Beef

Survival and growth of wild-type (EDL 933) and rpoS-deficient (FRIK 816-3) strains of Escherichia coli O157:H7 after exposure to an alkaline cleaner for 2 min and inoculating into roast beef (pH 6.3) and hard salami (pH 4.9) at low (0.003 to 0.52 CFU/g) and high (0.69 to 31.5 CFU/g) populations were determined. Roast beef was stored at 4 and 12°C; salami was stored at 4, 12, and 20°C. At 4°C, untreated cells of both strains showed greater reductions in populations in salami than in roast beef during a 21-day storage period. Populations of treated and untreated cells recovered from roast beef and salami stored at 4°C on tryptic soy agar were significantly (P ≤ 0.05) higher than on sorbitol MacConkey agar, indicating that a portion of the cells was injured. Treated and untreated cells grew in roast beef at 12°C. Growth of treated cells of the FRIK 816-3 strain in roast beef at 12°C was significantly slower than that of the EDL 933 strain. Populations of both strains decreased at different rates in salami stored at different temperatures (20°C > 12°C > 4°C). E. coli O157:H7 strain EDL 933 grew more rapidly at 20°C in a slurry (pH 5.97) prepared from stored salami (17 days at 20°C) on which Penicillium chrysogenum had grown than in a slurry (5.23) prepared from salami showing no mold growth. Within 2 to 3 days, populations were ca. 3 log CFU/ml higher in slurry made from infected salami than in control salami. Results indicate that treatment of E. coli O157: H7 with an alkaline cleaner for 2 min does not impair resuscitation and growth of surviving cells in roast beef at 12°C. Cross protection of cells exposed to an alkaline cleaner against subsequent stress conditions imposed by roast beef and salami stored at 4°C was not evident in either of the test strains.

Efficacy of Sanitizer Treatments on Survival and Growth Parameters of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on Fresh-Cut Pieces of Cantaloupe during Storage†

2015 ◽  
Vol 78 (7) ◽  
pp. 1288-1295 ◽  
Author(s):  
DIKE O. UKUKU ◽  
LIHAN HUANG ◽  
CHRISTOPHER SOMMERS
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Growth Parameters ◽  
Bacterial Pathogens ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Mesophilic Bacteria ◽  
Survival And Growth ◽  
Fresh Cut

For health reasons, people are consuming fresh-cut fruits with or without minimal processing and, thereby, exposing themselves to the risk of foodborne illness if such fruits are contaminated with bacterial pathogens. This study investigated survival and growth parameters of Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and aerobic mesophilic bacteria transferred from cantaloupe rind surfaces to fresh-cut pieces during fresh-cut preparation. All human bacterial pathogens inoculated on cantaloupe rind surfaces averaged ~4.8 log CFU/cm2, and the populations transferred to fresh-cut pieces before washing treatments ranged from 3 to 3.5 log CFU/g for all pathogens. A nisin-based sanitizer developed in our laboratory and chlorinated water at 1,000 mg/liter were evaluated for effectiveness in minimizing transfer of bacterial populations from cantaloupe rind surface to fresh-cut pieces. Inoculated and uninoculated cantaloupes were washed for 5 min before fresh-cut preparation and storage of fresh-cut pieces at 5 and 10°C for 15 days and at 22°C for 24 h. In fresh-cut pieces from cantaloupe washed with chlorinated water, only Salmonella was found (0.9 log CFU/g), whereas E. coli O157:H7 and L. monocytogenes were positive only by enrichment. The nisin-based sanitizer prevented transfer of human bacteria from melon rind surfaces to fresh-cut pieces, and the populations in fresh-cut pieces were below detection even by enrichment. Storage temperature affected survival and the growth rate for each type of bacteria on fresh-cut cantaloupe. Specific growth rates of E. coli O157:H7, Salmonella, and L. monocytogenes in fresh-cut pieces were similar, whereas the aerobic mesophilic bacteria grew 60 to 80% faster and had shorter lag phases.

Survival and Growth of Escherichia coli O157:H7 Inoculated onto Cut Lettuce Before or After Heating in Chlorinated Water, Followed by Storage at 5 or 15°C

2001 ◽  
Vol 64 (3) ◽  
pp. 305-309 ◽  
Author(s):  
YUE LI ◽  
ROBERT E. BRACKETT ◽  
JINRU CHEN ◽  
LARRY R. BEUCHAT
Keyword(s):  
Escherichia Coli ◽  
Escherichia Coli O157 ◽  
Marked Influence ◽  
E Coli ◽  
Iceberg Lettuce ◽  
Survival And Growth ◽  
Fresh Cut ◽  
Subsequent Storage ◽  
Efficacy Of Treatment ◽  
Treatment Water

This study determined the effects of mild heat and chlorine treatment followed by storage for up to 18 days at 5°C or 7 days at 15°C on the survival and growth of Escherichia coli O157:H7 inoculated onto fresh-cut iceberg lettuce. The efficacy of treatment with 20 ppm chlorine in killing the pathogen on lettuce at 50°C was determined. Treatment of lettuce with 20 ppm chlorine at either 20 or 50°C did not result in significantly greater reductions in populations of E. coli O157:H7 compared to respective treatments in water without chlorine. The pathogen steadily decreased in viability on treated lettuce throughout subsequent storage at 5°C for 18 days. The population increased by 2.3 to 3.2 log10 CFU/g within 2 days, then continued to increase at a slower rate through 7 days of storage at 15°C. At 4 and 7 days, significantly (α = 0.05) higher populations were reached on lettuce that had been treated at 50°C, compared to respective samples that had been treated at 20°C, regardless of the presence of 20 ppm chlorine in the treatment water. Treatment of lettuce with 20 ppm chlorine at 50 or 20°C before or after inoculation with E. coli O157:H7 did not have a marked influence on behavior of the pathogen during subsequent storage at 5 or 15°C.

Survival and Growth of Listeria monocytogenes and Escherichia coli O157:H7 in Ready-to-Eat Iceberg Lettuce Washed in Warm Chlorinated Water

2002 ◽  
Vol 65 (3) ◽  
pp. 459-464 ◽  
Author(s):  
PASCAL DELAQUIS ◽  
SANDRA STEWART ◽  
SANDRA CAZAUX ◽  
PETER TOIVONEN
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Iceberg Lettuce ◽  
Before And After ◽  
Survival And Growth ◽  
Spoilage Microflora ◽  
Storage Temperatures

Cut iceberg lettuce inoculated with Escherichia coli O157:H7 and Listeria monocytogenes before and after washing for 3 min in cold (4°C) and warm (47°C) water containing 100 mg/liter total chlorine was stored at 1 and 10°C in oxygen-permeable film packages (6,000 to 8,000 cc/m2/24 h). Cold chlorinated water was detrimental to the survival of E. coli O157: H7 and L. monocytogenes at both storage temperatures. In contrast, washing in warm chlorinated water favored the growth of both pathogens in lettuce stored at 10°C. There was no evidence of a relationship between the magnitude of spoilage microflora and the fate of either bacterium.

Fate of Escherichia coli O157:H7 and Listeria monocytogenes in Strawberry Juice and Acidified Media at Different pH Values and Temperatures†

2004 ◽  
Vol 67 (11) ◽  
pp. 2443-2449 ◽  
Author(s):  
Y. HAN ◽  
R. H. LINTON
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Ph Value ◽  
Escherichia Coli O157 ◽  
Bacterial Survival ◽  
E Coli ◽  
Ph Values ◽  
The Media ◽  
Survival And Growth ◽  
Strawberry Juice

Survival and growth of Escherichia coli O157:H7 and Listeria monocytogenes in strawberry juice and acidified media at different pH levels (pH 3.4 to 6.8) and temperatures were studied. Sterile strawberry juice (pH 3.6) and acidified trypticase soy broth (TSB) media (pH 3.4 to 6.8) were inoculated with approximately 6.7 log CFU/ml E. coli O157:H7 or 7.3 log CFU/ml L. monocytogenes, incubated for 3 days at 4 and 37°C. Bacterial levels were determined after 2 h, 1 day, and 3 days using surface plating nonselectively on tryptic soy agar and selectively on sorbitol MacConkey agar for E. coli O157:H7 or modified Oxford agar for L. monocytogenes. A spectrophotometer (660 nm) was also used to study growth inhibition of L. monocytogenes in different TSB and strawberry juice media (pH 3.4 to 7.3). E. coli O157:H7 survived well at pH values of 3.4 to 6.8 at 4°C, but the number of injured cells increased as pH decreased and incubation time increased. At 37°C, E. coli O157:H7 was inactivated at pH of ≤3.6 but could grow at pH 4.7. L. monocytogenes was quickly injured at pH of ≤4.7 within 2 h of storage at 4°C and then was slightly and gradually inactivated as storage time increased. L. monocytogenes survived well at pH 6.8 at 4°C and grew well at 37°C. Growth of L. monocytogenes at 37°C was inhibited in TSB by 1% citric acid and 0.5% malic acids at pH 3.4 or by 50% strawberry juice at pH 4.7. Bacterial injury and inactivation appeared to be induced by the acids in strawberry juice. The acids, pH value, temperature, and time were important factors for bacterial survival, inactivation, and growth in the media tested.

Antimicrobial Effects of Zataria multiflora and Ocimum basilicum on Escherichia coli O157:H7 During Ripening of Traditional Lighvan Cheese

2020 ◽  
Vol 16 (3) ◽  
pp. 373-380
Author(s):  
Mohammad B. Zendeh ◽  
Vadood Razavilar ◽  
Hamid Mirzaei ◽  
Khosrow Mohammadi
Keyword(s):  
Escherichia Coli ◽  
Essential Oils ◽  
Dairy Products ◽  
Antimicrobial Agents ◽  
Escherichia Coli O157 ◽  
Zataria Multiflora ◽  
Antimicrobial Effects ◽  
E Coli ◽  
Common Causes ◽  
Lighvan Cheese

Background: Escherichia coli O157:H7 is one of the most common causes of contamination in Lighvan cheese processing. Using from natural antimicrobial essential oils is applied method to decrease the rate of microbial contamination of dairy products. The present investigation was done to study the antimicrobial effects of Z. multiflora and O. basilicum essential oils on survival of E. coli O157:H7 during ripening of traditional Lighvan cheese. Methods: Leaves of the Z. multiflora and O. basilicum plants were subjected to the Clevenger apparatus. Concentrations of 0, 100 and 200 ppm of the Z. multiflora and 0, 50 and 100 ppm of O. basilicum essential oils and also 103 and 105 cfu/ml numbers of E. coli O157:H7 were used. The numbers of the E. coli O157:H7 bacteria were analyzed during the days 0, 30, 60 and 90 of the ripening period. Results: Z. multiflora and O. basilicum essential oils had considerable antimicrobial effects against E. coli O157:H7. Using the essential oils caused decrease in the numbers of E. coli O157:H7 bacteria in 90th days of ripening (P <0.05). Using from Z. multiflora at concentration of 200 ppm can reduce the survival of E. coli O157:H7 in Lighvan cheese. Conclusion: Using Z. multiflora and O. basilicum essential oils as good antimicrobial agents can reduce the risk of foodborne bacteria and especially E. coli O157:H7 in food products.

An Aggregation-Induced Emission Material Labeling Antigen-Based Lateral Flow Immunoassay Strip for Rapid Detection of Escherichia coli O157:H7

2021 ◽  
pp. 247263032098193
Author(s):  
Cheng Liu ◽  
Shuiqin Fang ◽  
Yachen Tian ◽  
Youxue Wu ◽  
Meijiao Wu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rapid Detection ◽  
Foodborne Pathogen ◽  
Test Strip ◽  
Lateral Flow ◽  
Detection Sensitivity ◽  
Lateral Flow Immunoassay ◽  
Escherichia Coli O157 ◽  
Aggregation Induced Emission ◽  
E Coli

Escherichia coli O157:H7 ( E. coli O157:H7) is a dangerous foodborne pathogen, mainly found in beef, milk, fruits, and their products, causing harm to human health or even death. Therefore, the detection of E. coli O157:H7 in food is particularly important. In this paper, we report a lateral flow immunoassay strip (LFIS) based on aggregation-induced emission (AIE) material labeling antigen as a fluorescent probe for the rapid detection of E. coli O157:H7. The detection sensitivity of the strip is 105 CFU/mL, which is 10 times higher than that of the colloidal gold test strip. This method has good specificity and stability and can be used to detect about 250 CFU of E. coli O157:H7 successfully in 25 g or 25 mL of beef, jelly, and milk. AIE-LFIS might be valuable in monitoring food pathogens for rapid detection.

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