Inactivation of Escherichia coli O157:H7 in Minute Steaks Cooked under Selected Conditions

2017 ◽  
Vol 80 (10) ◽  
pp. 1641-1647
Author(s):  
Xianqin Yang ◽  
Julia Devos ◽  
Mark D. Klassen
Keyword(s):  
Escherichia Coli ◽  
Cooking Time ◽  
Escherichia Coli O157 ◽  
Time Intervals ◽  
Hot Plate ◽  
E Coli ◽  
Cooking Practices ◽  
Medium Level ◽  
The Mean ◽  
Pan Frying

ABSTRACT A national survey was conducted in Canada to determine consumer cooking practices for minute steaks (thin, mechanically tenderized beef cutlets). Results indicate that most Canadians prefer cooking minute steaks by pan frying and to a medium level of doneness. To identify safe cooking conditions, retail minute steaks (∼125 g), inoculated at three sites per steak with a five-strain cocktail of nontoxigenic Escherichia coli O157:H7 (6.1 log CFU per site), were cooked on a hot plate (200°C), mimicking a pan-frying scenario. The steaks (n = 5) were cooked for 4, 6, 8, or 10 min with turning over (flipping) up to four times at equal time intervals; or to 63 or 71°C at the thickest area with or without a tinfoil lid. When cooked for 4 min, E. coli O157:H7 was recovered from all inoculation sites, and the mean reductions at various sites (1.2 to 3.4 log CFU per site) were not different (P > 0.05), irrespective of the flipping frequency. When cooked for 6 min with flipping once or twice, or for 8 min with flipping once, E. coli O157:H7 was recovered from most sites; the mean reductions (3.8 to 5.3 log CFU per site) were not different (P > 0.05), but they were higher (P < 0.05) than those for steaks cooked for 4 min. When cooked for 10, 8, or 6 min with flipping once, twice, or three times, respectively, E. coli O157:H7 was eliminated from most sites, but sites with <5-log reductions were found. Reductions of E. coli O157:H7 by >5 log at all inoculation sites were attained when the steaks were cooked for 10 or 8 min with two or more or three or more flippings, respectively, or for 6 min with four flippings. When flipped twice during cooking to 63 or 71°C, E. coli O157:H7 was recovered from three or fewer sites; however, >5-log reductions throughout the steaks were only attained for the latter temperature, irrespective of whether the hot plate was covered with the tinfoil lid. Thus, turning over minute steaks twice during cooking to 71°C or flipping two, three, or four times with a cooking time of 10, 8, or 6 min could achieve 5-log reductions throughout the steaks.

Survival of Enterohemorrhagic Escherichia coli O157:H7 in Retail Mustard

2001 ◽  
Vol 64 (6) ◽  
pp. 783-787 ◽  
Author(s):  
CAROLYN M. MAYERHAUSER
Keyword(s):  
Escherichia Coli ◽  
Foodborne Illness ◽  
Enterohemorrhagic Escherichia Coli ◽  
Test Strain ◽  
Escherichia Coli O157 ◽  
Time Intervals ◽  
Fermented Sausage ◽  
Apple Cider ◽  
E Coli ◽  
Predetermined Time

Escherichia coli O157:H7 survival in acid foods such as unpasteurized apple cider and fermented sausage is well documented. Researchers have determined that E. coli O157:H7 can survive in refrigerated acid foods for weeks. The potential of acid foods to serve as a vector of E. coli O157:H7 foodborne illness prompted this study to determine the fate of this organism in retail mustard containing acetic acid when stored at room and refrigerated temperatures. Various retail brands of dijon, yellow, and deli style mustard, pH ranging from 3.17 to 3.63, were inoculated individually with three test strains of E. coli O157:H7. Samples were inoculated with approximately 1.0 × 106 CFU/g, incubated at room (25 ± 2.5°C) and refrigerated (5 ± 3°C) temperatures, and assayed for surviving test strains at predetermined time intervals. An aliquot was appropriately diluted and plated using sorbitol MacConkey agar (SMAC). When the test strain was not recoverable by direct plating, the sample was assayed by enrichment in modified tryptic soy broth and recovered using SMAC. Growth of E. coli O157:H7 test strains was inhibited in all retail mustard styles. E. coli O157:H7 was not detected in dijon style mustard beyond 3 h at room and 2 days at refrigerated temperatures. Survival in yellow and deli style mustard was not detected beyond 1 h. Overall, test strain survival was greater at refrigerated than room temperature. Retail mustard demonstrated the ability to eliminate effectively any chance contamination by this organism within hours to days, suggesting that these products are not a likely factor in E. coli O157:H7 foodborne illness.

scholarly journals Salmonella and Escherichia coli O157:H7 Survival in Soil and Translocation into Leeks (Allium porrum) as Influenced by an Arbuscular Mycorrhizal Fungus (Glomus intraradices)

2013 ◽  
Vol 79 (6) ◽  
pp. 1813-1820 ◽  
Author(s):  
Joshua B. Gurtler ◽  
David D. Douds ◽  
Brian P. Dirks ◽  
Jennifer J. Quinlan ◽  
April M. Nicholson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Glomus Intraradices ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Allium Porrum ◽  
Escherichia Coli O157 ◽  
Content Type ◽  
E Coli ◽  
The Mean

ABSTRACTA study was conducted to determine the influence of arbuscular mycorrhizal (AM) fungi onSalmonellaand enterohemorrhagicEscherichia coliO157:H7 (EHEC) in autoclaved soil and translocation into leek plants. Six-week-old leek plants (with [Myc+] or without [Myc−] AM fungi) were inoculated with composite suspensions ofSalmonellaor EHEC at ca. 8.2 log CFU/plant into soil. Soil, root, and shoot samples were analyzed for pathogens on days 1, 8, 15, and 22 postinoculation. Initial populations (day 1) were ca. 3.1 and 2.1 log CFU/root, ca. 2.0 and 1.5 log CFU/shoot, and ca. 5.5 and 5.1 CFU/g of soil forSalmonellaand EHEC, respectively. Enrichments indicated that at days 8 and 22, only 31% of root samples were positive for EHEC, versus 73% positive forSalmonella. The meanSalmonellalevel in soil was 3.4 log CFU/g at day 22, while EHEC populations dropped to ≤0.75 log CFU/g by day 15. Overall,Salmonellasurvived in a greater number of shoot, root, and soil samples, compared with the survival of EHEC. EHEC was not present in Myc− shoots after day 8 (0/16 samples positive); however, EHEC persisted in higher numbers (P= 0.05) in Myc+ shoots (4/16 positive) at days 15 and 22.Salmonella, likewise, survived in statistically higher numbers of Myc+ shoot samples (8/8) at day 8, compared with survival in Myc− shoots (i.e., only 4/8). These results suggest that AM fungi may potentially enhance the survival ofE. coliO157:H7 andSalmonellain the stems of growing leek plants.

Effects of Selected Cooking Procedures on the Survival of Escherichia coli O157:H7 in Inoculated Steaks Cooked on a Hot Plate or Gas Barbecue Grill

2014 ◽  
Vol 77 (6) ◽  
pp. 919-926 ◽  
Author(s):  
C. O. GILL ◽  
J. DEVOS ◽  
M. K. YOUSSEF ◽  
X. YANG
Keyword(s):  
Escherichia Coli ◽  
Central Plane ◽  
Escherichia Coli O157 ◽  
Hot Plate ◽  
E Coli ◽  
Microbiological Safety ◽  
Beef Steaks

Beef steaks (2 cm thick) were each inoculated at three sites in the central plane with Escherichia coli O157:H7 at 5.9 ± 0.3 log CFU per site. Temperatures at steak centers were monitored during cooking on a hot plate or the grill of a gas barbeque. Steaks were cooked in groups of five using the same procedures and cooking each steak to the same temperature, and surviving E. coli O157:H7 at each site was enumerated. When steaks cooked on the hot plate were turned over every 2 or 4 min during cooking to between 56 and 62°C, no E. coli O157:H7 was recovered from steaks cooked to ≥58 or 62°C, respectively. When steaks were cooked to ≤71°C and turned over once during cooking, E. coli O157:H7 was recovered from steaks in groups turned over after ≤8 min but not from steaks turned over after 10 or 12 min. E. coli O157:H7 was recovered in similar numbers from steaks that were not held or were held for 3 min after cooking when steaks were turned over once after 4 or 6 min during cooking. When steaks were cooked on the grill with the barbeque lid open and turned over every 2 or 4 min during cooking to 63 or 56°C, E. coli O157:H7 was recovered from only those steaks turned over at 4-min intervals and cooked to 56°C. E. coli O157:H7 was recovered from some steaks turned over once during cooking on the grill and held or not held after cooking to 63°C. E. coli O157:H7 was not recovered from steaks turned over after 4 min during cooking to 60°C on the grill with the barbeque lid closed or when the lid was closed after 6 min. Apparently, the microbiological safety of mechanically tenderized steaks can be assured by turning steaks over at intervals of about 2 min during cooking to ≥60°C in an open skillet or on a barbecue grill. When steaks are turned over only once during cooking to ≥60°C, microbiological safety may be assured by covering the skillet or grill with a lid during at least the final minutes of cooking.

Identification of Escherichia coli O157:H7 Meat Processing Indicators for Fresh Meat through Comparison of the Effects of Selected Antimicrobial Interventions

2005 ◽  
Vol 68 (12) ◽  
pp. 2580-2586 ◽  
Author(s):  
K. M. MARSHALL ◽  
S. E. NIEBUHR ◽  
G. R. ACUFF ◽  
L. M. LUCIA ◽  
J. S. DICKSON
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Beef Cattle ◽  
Tissue Sample ◽  
Tissue Type ◽  
Escherichia Coli O157 ◽  
Fresh Meat ◽  
E Coli ◽  
The Mean ◽  
Beef Carcass

Fresh meat products can become contaminated with the pathogen Escherichia coli O157:H7 during the slaughter process; therefore, an E. coli O157:H7 indicator to verify the effectiveness of process controls in slaughter establishments would be extremely useful. The hides of 20 beef cattle were sampled, and 113 bacterial isolates were obtained. Thirteen of these isolates representing four genera, Escherichia, Enterobacter, Providencia, and Serratia, were selected based on growth and biochemical characteristics similar to those of five clinical strains of E. coli O157:H7. The temperature sensitivity was determined for the individual isolates and the five E. coli O157:H7 strains at 55 and 65°C. D65-values for all 13 isolates were not significantly different from D65-values of the E. coli O157:H7 strains. E. coli isolates were the only isolates whose D55-values were not significantly different from those of the E. coli O157:H7 strains. E. coli isolates P3 and P68 were more resistant to the effects of 55°C than were the other E. coli isolates but were not significantly different from E. coli O157:H7 WS 3331 (P > 0.05). The remaining E. coli isolates (P1, P8, and P14) were not significantly different from E. coli O157:H7 strains ATCC 35150, ATCC 43894, ATCC 43895, and WS 3062 (P > 0.05). Prerigor lean and adipose beef carcass tissue was artificially contaminated with stationary-phase cultures of the five E. coli beef cattle isolates or a cocktail of five E. coli O157:H7 strains in a fecal inoculum. Each tissue sample was processed with the following microbial interventions: 90°C water; 90°C water followed by 55°C 2% lactic acid; 90°C water followed by 20°C 2% lactic acid; 20°C water followed by 20°C 2% lactic acid; 20°C water followed by 20°C 20 ppm chlorine; and 20°C water followed by 20°C 10% trisodium phosphate. The appropriateness of the E. coli isolates as potential E. coli O157:H7 indicators was dependent upon the microbial intervention utilized. For all microbial intervention methods applied irrespective of tissue type, the mean log reductions of at least two E. coli isolates were not significantly different from the mean log reduction of the E. coli O157:H7 cocktail (P > 0.05). Because of the frequent employment of multiple microbial interventions in the cattle industry, no single isolate can realistically represent the effectiveness of all microbial interventions for reduction of E. coli O157:H7. Thus, the use of a combination of E. coli isolates may be required to accurately predict the effectiveness of microbial intervention methods on the reduction of E. coli O157: H7 in beef carcass tissue.

Irradiation and Chlorination Effectively Reduces Escherichia coli O157:H7 Inoculated on Cilantro (Coriandrum sativum) without Negatively Affecting Quality

2004 ◽  
Vol 67 (10) ◽  
pp. 2092-2098 ◽  
Author(s):  
DENISE FOLEY ◽  
MEGAN EUPER ◽  
FRED CAPORASO ◽  
ANURADHA PRAKASH
Keyword(s):  
Escherichia Coli ◽  
Low Dose ◽  
Coriandrum Sativum ◽  
Escherichia Coli O157 ◽  
Time Intervals ◽  
E Coli ◽  
Log Reduction ◽  
Combination Treatments ◽  
Dose Irradiation ◽  
Sensory Tests

Cilantro (Coriandrum sativum) inoculated with Escherichia coli O157:H7 at levels approximating 107 CFU/g was dipped in 200 ppm chlorine solution followed by low-dose gamma irradiation. Samples were plated on tryptic soy agar containing 50 μg/ml nalidixic acid (TSAN) as well as TSAN plates with two 7-ml layers of basal yeast extract agar (TSAN-TAL). Levels of E. coli O157:H7 recovered from both types of media were determined over 11 days. Chlorination alone reduced counts by just over 1.0 log cycle, whereas irradiation at 1.05 kGy resulted in a 6.7-log reduction, and a combination of irradiation and chlorination reduced counts more than 7 log cycles. Trained panels performed analytical sensory tests at time intervals for 14 days to detect changes in yellowing, tip burn, browning, black rot, sliminess, off-aroma, and off-flavor. Sensory tests found no significant differences among attributes over time or dose in samples irradiated at 1.08 to 3.85 kGy. This study showed that combination treatments of chlorination and low-dose irradiation can significantly reduce levels of E. coli O157:H7 in fresh cilantro while maintaining product quality.

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.

Bacteriophages reduce Escherichia coli O157:H7 levels in experimentally inoculated sheep

2009 ◽  
Vol 89 (2) ◽  
pp. 285-293 ◽  
Author(s):  
S J Bach ◽  
R P Johnson ◽  
K. Stanford ◽  
T A McAllister
Keyword(s):  
Escherichia Coli ◽  
Oral Administration ◽  
Coliform Bacteria ◽  
Escherichia Coli O157 ◽  
Fecal Shedding ◽  
Total Coliforms ◽  
E Coli ◽  
Oral Inoculation ◽  
Experimental Treatments ◽  
And Control

Bacteriophage biocontrol has potential as a means of mitigating the prevalence of Escherichia coli O157:H7 in ruminants. The efficacy of oral administration of bacteriophages for reducing fecal shedding of E. coli O157:H7 by sheep was evaluated using 20 Canadian Arcott rams (50.0 ± 3.0) housed in four rooms (n = 5) in a contained facility. The rams had ad libitum access to drinking water and a pelleted barley-based total mixed ration, delivered once daily. Experimental treatments consisted of administration of E. coli O157:H7 (O157), E. coli O157:H7+bacteriophages (O157+phage), bacteriophages (phage), and control (CON). Oral inoculation of the rams with 109 CFU of a mixture of four nalidixic acid-resistant strains of E. coli O157:H7 was performed on day 0. A mixture of 1010 PFU of bacteriophages P5, P8 and P11 was administered on days -2, -1, 0, 6 and 7. Fecal samples collected on 14 occasions over 21 d were analyzed for E. coli O157:H7, total E. coli, total coliforms and bacteriophages. Sheep in treatment O157+phage shed fewer (P < 0.05) E. coli O157:H7 than did sheep in treatment O157. Populations of total coliforms and total E. coli were similar (P < 0.05) among treatments, implying that bacteriophage lysis of non-target E. coli and coliform bacteria in the gastrointestinal tract did not occur. Bacteriophage numbers declined rapidly over 21 d, which likely reduced the chance of collision between bacteria and bacteriophage. Oral administration of bacteriophages reduced shedding of E. coli O157:H7 by sheep, but a delivery system that would protect bacteriophages during passage through the intestine may increase the effectiveness of this strategy as well as allow phage to be administered in the feed.Key words: Escherichia coli O157:H7, bacteriophage, sheep, environment, coliforms

Surface and Internalized Escherichia coli O157:H7 on Field-Grown Spinach and Lettuce Treated with Spray-Contaminated Irrigation Water

2010 ◽  
Vol 73 (6) ◽  
pp. 1023-1029 ◽  
Author(s):  
MARILYN C. ERICKSON ◽  
CATHY C. WEBB ◽  
JUAN CARLOS DIAZ-PEREZ ◽  
SHARAD C. PHATAK ◽  
JOHN J. SILVOY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Irrigation Water ◽  
Enrichment Culture ◽  
Field Studies ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Adaxial Side ◽  
Abaxial Side ◽  
E Coli ◽  
Contaminated Irrigation Water

Numerous field studies have revealed that irrigation water can contaminate the surface of plants; however, the occurrence of pathogen internalization is unclear. This study was conducted to determine the sites of Escherichia coli O157:H7 contamination and its survival when the bacteria were applied through spray irrigation water to either field-grown spinach or lettuce. To differentiate internalized and surface populations, leaves were treated with a surface disinfectant wash before the tissue was ground for analysis of E. coli O157:H7 by direct plate count or enrichment culture. Irrigation water containing E. coli O157:H7 at 102, 104, or 106 CFU/ml was applied to spinach 48 and 69 days after transplantation of seedlings into fields. E. coli O157:H7 was initially detected after application on the surface of plants dosed at 104 CFU/ml (4 of 20 samples) and both on the surface (17 of 20 samples) and internally (5 of 20 samples) of plants dosed at 106 CFU/ml. Seven days postspraying, all spinach leaves tested negative for surface or internal contamination. In a subsequent study, irrigation water containing E. coli O157:H7 at 108 CFU/ml was sprayed onto either the abaxial (lower) or adaxial (upper) side of leaves of field-grown lettuce under sunny or shaded conditions. E. coli O157:H7 was detectable on the leaf surface 27 days postspraying, but survival was higher on leaves sprayed on the abaxial side than on leaves sprayed on the adaxial side. Internalization of E. coli O157:H7 into lettuce leaves also occurred with greater persistence in leaves sprayed on the abaxial side (up to 14 days) than in leaves sprayed on the adaxial side (2 days).

Tracking an Escherichia coli O157:H7–Contaminated Batch of Leafy Greens through a Pilot-Scale Fresh-Cut Processing Line

2014 ◽  
Vol 77 (9) ◽  
pp. 1487-1494 ◽  
Author(s):  
ANNEMARIE L. BUCHHOLZ ◽  
GORDON R. DAVIDSON ◽  
BRADLEY P. MARKS ◽  
EWEN C. D. TODD ◽  
ELLIOT T. RYSER
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Fluorescent Protein ◽  
Pilot Scale ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Leafy Greens ◽  
Iceberg Lettuce ◽  
Processing Line ◽  
Fresh Cut

Cross-contamination of fresh-cut leafy greens with residual Escherichia coli O157:H7–contaminated product during commercial processing was likely a contributing factor in several recent multistate outbreaks. Consequently, radicchio was used as a visual marker to track the spread of the contaminated product to iceberg lettuce in a pilot-scale processing line that included a commercial shredder, step conveyor, flume tank, shaker table, and centrifugal dryer. Uninoculated iceberg lettuce (45 kg) was processed, followed by 9.1 kg of radicchio (dip inoculated to contain a four-strain, green fluorescent protein–labeled nontoxigenic E. coli O157:H7 cocktail at 106 CFU/g) and 907 kg (2,000 lb) of uninoculated iceberg lettuce. After collecting the lettuce and radicchio in about 40 bags (~22.7 kg per bag) along with water and equipment surface samples, all visible shreds of radicchio were retrieved from the bags of shredded product, the equipment, and the floor. E. coli O157:H7 populations were quantified in the lettuce, water, and equipment samples by direct plating with or without prior membrane filtration on Trypticase soy agar containing 0.6% yeast extract and 100 ppm of ampicillin. Based on triplicate experiments, the weight of radicchio in the shredded lettuce averaged 614.9 g (93.6%), 6.9 g (1.3%), 5.0 g (0.8%), and 2.8 g (0.5%) for bags 1 to 10, 11 to 20, 21 to 30, and 31 to 40, respectively, with mean E. coli O157:H7 populations of 1.7, 1.2, 1.1, and 1.1 log CFU/g in radicchio-free lettuce. After processing, more radicchio remained on the conveyor (9.8 g; P &lt; 0.05), compared with the shredder (8.3 g), flume tank (3.5 g), and shaker table (0.1 g), with similar E. coli O157:H7 populations (P &gt; 0.05) recovered from all equipment surfaces after processing. These findings clearly demonstrate both the potential for the continuous spread of contaminated lettuce to multiple batches of product during processing and the need for improved equipment designs that minimize the buildup of residual product during processing.

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